SeniorDesignProjectReport

Ocean Going Salvage Vessel
A 10,570 BHP Salvage Vessel Preliminary Design by:
Sea Tools Engineering
Prepared By:
Daniel Place - Alex Donaldson - Marc Woolliscroft - Jacob Trithart
Undergraduate Students, Department of Naval Architecture and Marine Engineering
The University of Michigan
Prepared For:
Matthew Collette
Professor, Department of Naval Architecture and Marine Engineering
Administrator
Administrator, U.S. Maritime Administration
Capt. Lawson Brigham, USCG (Ret), PhD
Deputy Director, U.S. Arctic Research Commission
Mr. R. Keith Michel
President, Society of Naval Architects and Marine Engineers
Mr. Ronald Kiss
Past President, Webb Institute
Pradeep Nayyar
Program Manager, Maritime Administration, U.S. Department of Transportation
Project Due Date:
April 21, 2010

2
Table of Contents
List of Tables.................................................................................................................................. 4
List of Figures ................................................................................................................................ 6
1.0 – Executive Summary............................................................................................................... 7
2.0 – Technical Summary ............................................................................................................... 9
2.1 – Introduction........................................................................................................................ 9
2.2 - Requirements...................................................................................................................... 9
2.3 – Principal Characteristics .................................................................................................... 9
2.4 – Hull Selection................................................................................................................... 10
2.5 – General Arrangements ..................................................................................................... 10
2.6 – Engine Selection .............................................................................................................. 11
2.7 – Generator Selection.......................................................................................................... 11
2.8 – Propulsion Design............................................................................................................ 12
2.9 – Weights Estimation.......................................................................................................... 12
2.10 – Floodable Length ........................................................................................................... 12
2.11 – Damage Stability............................................................................................................ 13
2.12 – Midship Analysis ........................................................................................................... 13
2.13 – Seakeeping Analysis...................................................................................................... 13
2.14 – Maneuvering Analysis ................................................................................................... 14
2.15 – Conclusion ..................................................................................................................... 14
3.0 – Introduction.......................................................................................................................... 15
3.1 – Requirements ................................................................................................................... 15
3.2 – Principal Characteristics .................................................................................................. 15
4.0 – Hull Form Design ................................................................................................................ 16
4.1 – Initial Point Design .......................................................................................................... 16
4.2 –Hull Selection and Optimization....................................................................................... 16
4.3 – Lines Drawing.................................................................................................................. 17
5.0 – Capabilities .......................................................................................................................... 19
5.1 – Salvage............................................................................................................................. 19
5.2 – Towing............................................................................................................................. 19
5.3 – Fire Fighting..................................................................................................................... 19
5.4 – Oil Recovery.................................................................................................................... 20
6.0 – General Arrangements ......................................................................................................... 21
6.1 – Bulkhead Placement......................................................................................................... 21
6.2 – Floodable Length ............................................................................................................. 22
6.3 Deck House......................................................................................................................... 22
7.0 – Propulsion and Powering..................................................................................................... 25
7.1 – Resistance ........................................................................................................................ 25
7.2 – Prime Mover Selection .................................................................................................... 26
7.2.1 – Initial Point Design and Selection............................................................................. 26
7.2.2 – Analysis of Selected Engines.................................................................................... 26
7.3 – Propulsion Design............................................................................................................ 28
7.4 – Towing and Bollard Pull.................................................................................................. 30
7.5 – Electrical Power Estimation............................................................................................. 31
7.6 – Generator Selection.......................................................................................................... 31
7.7 – One Line Diagram............................................................................................................ 31
8.0 – Intact and Damage Stability................................................................................................. 33

3
8.1 – Intact Stability.................................................................................................................. 33
8.1.1 – U.S. Coast Guard Wind Heel Requirements............................................................. 33
8.1.2 – Towing Stability Criteria .......................................................................................... 33
8.1.3 – Topside Icing ............................................................................................................ 33
8.1.4 – Cross Curves of Stability.......................................................................................... 34
8.1.5 – Bonjean Curves......................................................................................................... 34
8.2 – Damaged Stability............................................................................................................ 35
9.0 – Midship Analysis ................................................................................................................. 37
9.1 – ABS Regulations.............................................................................................................. 37
9.2 – Moment and Shear Diagram ............................................................................................ 37
9.3 – Midship Analysis ............................................................................................................. 38
10.0 Structural Analysis................................................................................................................ 39
10.1 Ice Strengthened Regions ................................................................................................. 39
10.2 Framing............................................................................................................................. 40
11.0 – Maneuvering Analysis ....................................................................................................... 42
11.1 – Initial Sizing................................................................................................................... 42
11.2 – Maneuvering Prediction Program.................................................................................. 42
11.3 – Bow Thruster ................................................................................................................. 42
12.0 – Seakeeping Analysis.......................................................................................................... 44
12.1 – Seakeeper Results .......................................................................................................... 44
12.2 – Natural Periods............................................................................................................... 47
12.3 – Working Condition Analysis ......................................................................................... 47
13.0 – Fleet Justification............................................................................................................... 49
14.0 Economic Analysis ............................................................................................................... 51
15.0 – Recommendations for Future Work................................................................................... 55
16.0 – Conclusion ......................................................................................................................... 56
Appendix A – Lines Drawing....................................................................................................... 57
Appendix B – Outboard & Inboard Profiles................................................................................. 58
Appendix C – General Arrangements........................................................................................... 59
Appendix D – Propeller Geometry ............................................................................................... 60
Appendix E – Structural Drawings............................................................................................... 61
Appendix F – Powering Specifications......................................................................................... 62
Appendix G – Machinery Specifications...................................................................................... 63
Appendix H – Maneuvering.......................................................................................................... 64
Appendix I – Floodable Length.................................................................................................... 65
Appendix J – Intact Stability......................................................................................................... 66
Appendix K – Damaged Stability................................................................................................. 67
Appendix L – Seakeeping Results ................................................................................................ 68
Appendix M – Structural Calculations ......................................................................................... 69

4
List of Tables
Table 1 – Principal Characteristics ................................................................................................. 7
Table 2 – General Engine Characteristics....................................................................................... 8
Table 3 – Propeller Characteristics................................................................................................. 8
Table 4 – Principal Characteristics ............................................................................................... 10
Table 5 – Engine Characteristics .................................................................................................. 11
Table 6 – Generator Characteristics.............................................................................................. 11
Table 7 – Propeller Optimization Characteristics......................................................................... 12
Table 8 – Intact Stability at Four Loading Conditions ................................................................. 12
Table 9 – Midship Analysis.......................................................................................................... 13
Table 10 – Seakeeping Analysis................................................................................................... 14
Table 11 – Maneuvering Analysis ................................................................................................ 14
Table 12 – Client Requirements ................................................................................................... 15
Table 13 – Principal Characteristics ............................................................................................. 15
Table 14 – Regression Analysis Results....................................................................................... 16
Table 15 – Principal Dimensions and Hydrostatics...................................................................... 17
Table 16 – Station Spacing ........................................................................................................... 18
Table 17 – Salvage Characteristics............................................................................................... 19
Table 18 – Firefighting Characteristics......................................................................................... 20
Table 19 – Bulkhead Locations .................................................................................................... 21
Table 20 - Deckhouse Accommodations...................................................................................... 23
Table 21 - Percentage of Total Drag............................................................................................. 25
Table 22 – 8 Cylinder Engine Characteristics .............................................................................. 27
Table 23 – 16 Cylinder Engine Characteristics ............................................................................ 27
Table 24 – Propeller Characteristics............................................................................................. 28
Table 25 – Generator Characteristics............................................................................................ 31
Table 26 - MARAD Design Letter 3 Damaged Stability Criterion.............................................. 35
Table 27 – Damage Stability Results............................................................................................ 36
Table 28 – ABS Longitudinal Strength Calculations ................................................................... 37
Table 29 - Maximum Bending Moments...................................................................................... 37
Table 30 – Midship Section Strength Properties .......................................................................... 38
Table 32 – Ice Belt Definitions..................................................................................................... 39
Table 31 – Plating Thicknesses..................................................................................................... 39
Table 33 – Required and Actual Section Moduli.......................................................................... 40
Table 34 – Stiffener Sizing ........................................................................................................... 40
Table 35 – Maneuvering Analysis ................................................................................................ 42
Table 36 - North Pacific Sea State Characteristics ....................................................................... 44
Table 37 - Natural Periods............................................................................................................ 47
Table 38 - Worst Cast MII Results ............................................................................................... 47
Table 39 – MII Risk Levels .......................................................................................................... 48
Table 40 - Incidents near the Aleutian Island ............................................................................... 49
Table 41 - Crew Cost Breakdown................................................................................................. 51
Table 42 - Build Cost Breakdown ................................................................................................ 51
Table 43 - Operational Cost Breakdown ...................................................................................... 51
Table 44 - 15 Year Expense Summary ......................................................................................... 51
Table 45 - Salvage Revenue ......................................................................................................... 52

5
Table 46 - Specific Fuel Consumption ......................................................................................... 52
Table 47 - Average Fuel Prices..................................................................................................... 52
Table 48 - Dutch Harbor Fuel Cost............................................................................................... 53
Table 49 - Seattle Fuel Cost.......................................................................................................... 53
Table 50 - Juneau Fuel Cost.......................................................................................................... 53
Table 51 - Required Returns......................................................................................................... 53
Table 52 - Towing Summary........................................................................................................ 54
Table 53 - Required Freight Rate.................................................................................................. 54

6
List of Figures
Figure 1 – Lines Drawing ............................................................................................................. 10
Figure 2 – Inboard Profile............................................................................................................. 11
Figure 3 – Floodable Length Diagram.......................................................................................... 13
Figure 4 - Double Hard Chine Hull Form – LOA = 44.2 m......................................................... 17
Figure 5 - Faired Hull Form –....................................................................................................... 17
Figure 6 - Fire Monitor Location.................................................................................................. 20
Figure 7 - Interior General Arrangements .................................................................................... 21
Figure 8 – Bulkhead Placement.................................................................................................... 21
Figure 9 – Floodable Length Analysis.......................................................................................... 22
Figure 10 – Propulsion System Rendering ................................................................................... 25
Figure 11 - Total Resistance and Delivered Thrust versus Speed ................................................ 26
Figure 12 - Engine Layout Rendering .......................................................................................... 28
Figure 13 - Propeller and Kort Nozzles........................................................................................ 29
Figure 14 - Cavitation versus Vessel Speed ................................................................................. 29
Figure 15 - Propeller Coefficients versus Vessel Speed............................................................... 30
Figure 16 - 12,000 mt Barge (380' x 100') with 11' Draft............................................................. 31
Figure 17 - One-Line Diagram ..................................................................................................... 32
Figure 18 - Towline Pull Criterion................................................................................................ 33
Figure 19 – GZ Curves ................................................................................................................. 34
Figure 20 – Bonjean Curves ......................................................................................................... 35
Figure 21 – Load Distribution for the Full Load Condition ......................................................... 38
Figure 22 - Bow Thruster Regression........................................................................................... 43
Figure 23 - 16 kn RAO, 0º............................................................................................................ 44
Figure 24 - 16 kn RAO, 30º.......................................................................................................... 44
Figure 25 - 16 kn RAO, 90º.......................................................................................................... 45
Figure 26 - 16 kn RAO, 140º........................................................................................................ 45
Figure 27 - 16 kn RAO, 180º........................................................................................................ 45
Figure 28 - Heave Response ......................................................................................................... 46
Figure 29 - Roll Response............................................................................................................. 46
Figure 30 - Pitch Response ........................................................................................................... 46
Figure 31 - Critical MII Locations................................................................................................ 47
Figure 32 - Tug Fleet Locations.................................................................................................... 50

7
1.0 – Executive Summary
The Maritime Administration (the Agency) and the Society for Naval Architects and Marine
Engineers (SNAME) have expressed a strong need for the capabilities of a 10,000 horsepower
ocean going salvage tug in the proximity of the Aleutian Islands. It was the task of Sea Tools
Engineering to develop a preliminary design for such a tug. The initial requirements set forth by
the Agency and SNAME included a minimum 10,000 hp installed power, ice strengthened for
operation in and around the Aleutian Islands, and commercial operations, other than salvage,
which would break even on the vessel’s operating cost and amortize the build cost after 15 years.
The vessel was also to have a region of operation that would allow efficient response to salvage
missions and operate in a safe, secure, and environmentally responsible manner.
Sea Tools Engineering has successfully designed a tug as desired by the Agency and SNAME.
The tug will be United States flagged and therefore comply with the American Bureau of
Shipping (ABS) classification rules, United States Coast Guard requirements, and the Code of
Federal Regulations. The Sea Tools tug satisfies all of the client requirements, exceeds
classification standards, and has several unique features which make it a feasible choice for
deployment in the Aleutian Islands. The principal dimensions for the tug were determined via a
regression analysis of similar existing ocean going salvage tugs. Unique and important features
of the tug include Fire Fighting II classification, oil recovery capabilities, safe conditions for the
crew to pilot the vessel and operate the winch in sea state six, and a variable propulsion system
that reduces fuel consumption if full power be unnecessary. An overview of the principal
characteristics for the Sea Tools design is listed in Table 1.
LOA (m) 66.8
LWL (m) 65.6
B (m) 15.0
D (m) 7.49
T (m) 5.63
C 0.52B
Design Speed (kn) 16
Displacement (MT) 2941
Endurance (nm) 2640
Installed Power (kW) 7882
Bollard Pull (tons-force) 129.7
Crew Capacity 30
Cost (millions USD) 26.8
Table 1 – Principal Characteristics
The floodable length and damaged stability characteristics of the Sea Tools tug are outstanding
and will survive a head on collision resulting in failure of the collision bulkhead. The powering
analysis and propeller optimization determined the tug has exceptional bollard pull and minimal
cavitation during the bollard pull condition. Powering characteristics are presented in Table 2
and propeller characteristics are presented in Table 3.

8
MCREngine 7,882 kW (10,570 BHP) @ 800 rpm(kW)
Engines 4
Brand ElectroMotive
Models EMD 8-710GC-T2 and EMD 16-710GC-T2
Table 2 – General Engine Characteristics
Characteristic Value
Quantity 2
DP 4.0 m
P controllable
AE/AO 0.85
RPM 188 rpm
Maximum Efficiency 46 %
Table 3 – Propeller Characteristics
The tug is economically viable and will break even after 15 years of operation. This will be
accomplished by performing towing operations between Seattle and Juneau in addition to
salvage missions. A fleet of three vessels will be utilized which will leave at least one tug on call
at all times for salvage missions. Each Sea Tools tug will require a crew of 12 and is prepared to
house 18 additional salvors. Each sailor has ample room in the deckhouse and will be
comfortable when performing extended length salvage missions.
This report is a preliminary design and contains details of the hull design and optimization,
propeller optimization and selection, weight estimation and weight centers, powering
calculations, damaged stability, structures, maneuvering and seakeeping predictions, and
economic analysis.

9
2.0 – Technical Summary
A summary of the technical aspects of the report are summarized in this section.
2.1 – Introduction
It has been indicated by the Society of Naval Architects and Marine Engineers, as well as the
United States Maritime Administration, that there is currently a strong need for powerful, 10,000
BHP, ocean going salvage vessels in and around the Aleutian Islands and Gulf of Alaska.
Because of this need, these organizations have put forth a design competition, in which we have
partaken, in order to fulfill this design need. Our preliminary design not only fulfills all
necessary salvage operations, but also implements several other commercial applications in order
pay for the costs of the vessel over a 15 year period. The remaining details of our vessel design
are presented in this report. Details include principal dimensions, hull regression and selection,
general arrangement, prime mover and machinery selections, propulsion design, weight and
centers estimation, ship intact and damage stability, floodable length, structural analysis of the
midship section, a seakeeping analysis, and a maneuvering estimation.
2.2 - Requirements
The requirements which governed the design of our vessel are listed below.
MARAD and SNAME Design Competition Requirements
• Location: Aleutian Islands Chain & Arctic Waters
• Power: Minimum of 10,000 HP (7,457 kW) installed
• Structure: Ice strengthened for Arctic waters
• Economic: Commercial applications other than salvaging
Break even with costs after 15 years of continuous operation
• Response: Fast response time from doing other commercial applications
• Operation: Safe, secure and environmentally responsible
Designer Specified Requirements
• Seakeeping: Operate safely in conditions up to sea state six
2.3 – Principal Characteristics
The principal dimensions for the salvage vessel were determined via a regression analysis of
similar existing containerships and iterated until the best solution was found. Developing a brand
new hull form can be a very expensive process and unnecessary if many similar vessels have
been previously contracted. Initial dimensions for the Sea Tools tug hull form were found
through a regression analysis of 28 previously constructed ocean going salvage tugs of similar
power and capabilities. Principal characteristics are listed in Table 4.

10
LOA (m) 66.8
LWL (m) 65.6
B (m) 15.0
D (m) 7.49
T (m) 5.63
C 0.52B
Displacement (MT) 2941
Endurance (nm) 2640
Installed Power (kW) 7882
Bollard Pull 129.7
2.4 – Hull Selection
Maxsurf was utilized to digitize an existing body plan and lines drawing of a hard chine hull
form and parametrically transformed to the target dimensions found from the regression analysis.
The lines drawing for the salvage vessel can be found in Figure 1.
Figure 1 – Lines Drawing
2.5 – General Arrangements
The general arrangements for the salvage vessel were modeled in Rhinoceros NERBs software
and AutoCAD. The inboard profile arrangement can be seen in Figure 2.

11
Figure 2 – Inboard Profile
2.6 – Engine Selection
The selection of the engines to be installed aboard the salvage vessel was based on rigorous
research of similar existing vessels and research done on several manufacturers. It was
determined, based on this research, that ElectroMotive diesel engines would be installed aboard
the vessel. The prime mover’s primary characteristics can be seen in Table 5.
Cylinders 8
Fuel Consumption Rate (t/kW*hr) 0.00020438
Brand ElectroMotive
Model EMD 8-710GC-T2
Cylinders 16
Brand ElectroMotive
Table 5 – Engine Characteristics
2.7 – Generator Selection
The electrical load of the design is initially estimated as the sum of the following machinery and
controls plus a twenty percent preliminary design margin: crane, winch, hotel/deckhouse service,
fire monitor controls, machinery pumps and controls, bow thruster, etc. Sea Tools recommends
the installation of two 1,550 kW Caterpillar 3512C generators in order to design redundantly in
case of failure. Table 6 illustrates the required and installed power on the vessel design.
Required (kW) Installed (kW)
Average at Sea Service Load 750 3,100
Maximum at Sea Service Load 1,525 3,100
Emergency Power 153 158
Table 6 – Generator Characteristics

12
2.8 – Propulsion Design
The propeller design in the particular case of the tug style vessel was fairly difficult because it
was necessary to maximize thrust at low speeds while also maximizing over all vessel speed for
quick response time to salvage operations. This was done using NavCad 2007 and produced two
controllable pitch propellers housed within ka-19a Kort nozzles to maximize thrust. The
optimized propeller results are given in Table 7.
Quantity 2
DP 4.0 m
P controllable
AE/AO 0.85
RPM 188 rpm
Table 7 – Propeller Optimization Characteristics
2.9 – Weights Estimation
Four operating conditions were analyzed using the arrangements from the Rhino 3D model to
estimate the centers of all machinery, structure, plating, and design margins. These conditions
were used to analyze the maximum bending moment. Stability properties for each condition can
be found in Table 8.
GMT GM(m) L T(m) F T(m) A Trim (cm, + by stern)(m) KG (m)
Full Load Departure 3.19 76.5 5.63 5.63 0 4.9
50 % Fuel Remaining 3.14 78.4 4.99 5.86 87 5.1
10 % Fuel Remaining 3.19 76.5 5.50 5.74 24 4.9
Topside Icing 3.16 76.2 5.56 5.73 18 4.9
Table 8 – Intact Stability at Four Loading Conditions
2.10 – Floodable Length
A floodable length analysis was performed to determine if the bulkhead placement in the design
provided adequate number of watertight compartments to maintain a floating vessel in case of
damage. The vessel passes all single compartment flooding criteria as well as the two
compartment case for both forward-most compartments flooded. The test result diagram is
shown in Figure 3.

13
Figure 3 – Floodable Length Diagram
2.11 – Damage Stability
Requirements governing compartment flooding survival for uninspected tugs do not exist.
However, safe operation in damaged conditions was a primary concern for the Sea Tools tug.
One compartment flooding for all compartments was determined to be a necessary requirement
in addition to two compartment flooding in the two bow compartments. The MARAD Design
Letter 3 was used for damaged stability to determine if the Sea Tools tug would remain stable in
each damaged condition. These criteria were selected because they are relatively conservative
compared to other rule sets which could have been used for this vessel.
2.12 – Midship Analysis
ABS requirements specified strength requirements for our vessel design, which was verified by
analyzing the midship section and the winch location’s framing. The requirements and actual
values for our vessel design are listed in Table 9.
ABS Required Actual Units
SM deck 3202 29,220 cm2
-m
SM bottom 3202 16,390 cm2
-m
Table 9 – Midship Analysis
2.13 – Seakeeping Analysis
Maxsurf’s Seakeeper program was used to analyze the seakeeping properties of our design at Sea
States four, five, and six. The results from the seakeeping analysis are listed in Table 10, and
they represent, on average, how many interruptions a one will experience in one hour based on
the given sea state. These values are well within a reasonable realm for working in up to sea state
six at full speed.

14
Motion-Induced Interruptions per hour
SS4 SS5 SS6
Wheelhouse 5.6 18.0 16.5
Winch Controls 8.2 19.4 18.3
Table 10 – Seakeeping Analysis
2.14 – Maneuvering Analysis
The University of Michigan’s Maneuvering Prediction Program (MPP) was used to determine
the rudder area necessary to meet turning requirements. The required rudder area was calculated
to be 11.1 m2
Table 11. The maneuvering results from MPP are listed in .
Required Calculated
Advance (m) <295.2 852.95
Tactical Diameter (m) <328 312.8
Clarke’s Turning Index >0.4 11.3
Linear Dynamic Stability >0.0 0.00041
Table 11 – Maneuvering Analysis
2.15 – Conclusion
This proposed design is an ideal candidate for meeting all requirements set forth by
MARAD/SNAME and exceeds the minimum classification and safety requirements. The
proposed design has excellent stability properties at several loading conditions, a viable
efficiency, and an economically sound business model.

15
3.0 – Introduction
With the expansion of the oil industry, increased commercial shipping traffic, and a greater
knowledge of the effects of environmental safety, the need for high-powered salvage tugs near
the Aleutian Island Chain and the Gulf of Alaska is growing. The unpredictability of the need
for salvaging requires designs to be versatile in their capabilities. While not salvaging,
commercial operations act as a valuable source of additional income. However, during the event
of an emergency, a fast response time and the ability to abort commercial operations become
essential. The design enclosed fully meets these necessities as well as the requirements set forth
by the MARAD/SNAME student design competition.
3.1 – Requirements
The client requirements for the salvage tug are shown in Table 12.
Power Minimum of 10,000 HP (7,457 kW) installed
Location Aleutian Islands Chain & Arctic Waters
Economic
Commercial applications other than salvaging
Break even with costs after 15 years of continuous
operation
Structure Ice strengthened for Arctic waters
Response
Fast response time from doing other commercial
applications
Operation Safe, secure and environmentally responsible
Table 12 – Client Requirements
3.2 – Principal Characteristics
The principal characteristics of the salvage tug design are listed in Table 13.
LOA (m) 66.8
LWL (m) 65.6
B (m) 15.0
D (m) 7.49
T (m) 5.63
C 0.52B
Displacement (MT) 2,941
Endurance (nm) 2,640
Installed Power (kW) 7,882
Crew 12
Cost (millions USD) 26.8

16
4.0 – Hull Form Design
Parametric transformation in Maxsurf was utilized to cater a parent hull to the final hull form for
the Sea Tools salvage tug. The hull form was designed with consideration for reducing the cost
and ease of construction while having favorable stability and seakeeping characteristics.
4.1 – Initial Point Design
Developing a brand new hull form can be a very expensive process and unnecessary if many
similar vessels have been previously contracted. Initial dimensions for the Sea Tools tug hull
form were found through a regression analysis of 28 previously constructed ocean going salvage
tugs of similar power and capabilities. The regressions performed utilized one linear term versus
installed power. The largest correlation coefficient (0.50) was obtained from the draft versus
installed power regression. This is a small correlation coefficient, but this can be attributed to
the small pool of tugs analyzed, and the fact that each tug included in the regression was
designed with certain requirements, which would over- or undersize certain characteristics.
However, the values produced from the regression analysis provided an initial starting point from
which to develop the principal dimensions for the Sea Tools tug. The results of the regression
analysis are tabulated in Table 14.
Regression Variables Result
LOA vs. Installed Power 71.5 m
LBP vs. Installed Power 59.8 m
B vs. Installed Power 15.0 m
T vs. Installed Power 6.0 m
D vs. Installed Power 7.5 m
Speed vs. Installed Power 16.1 kn
Bollard Pull vs. Installed Power 115 tons-force
Table 14 – Regression Analysis Results
These values were essential for developing the principal dimensions of AHAB but were not the
final dimensions used. These dimensions were used to initially transform a parent hull and
further analysis of the transformed hull form was required to finalize the hull dimensions.
4.2 –Hull Selection and Optimization
The hull forms of two previously constructed ocean going salvage tugs were considered to
become the parent hull for the Sea Tools tug. The first hull considered was a double hard chine
and ice strengthened tug seen in Figure 4. The advantage of choosing this design as the parent
hull was its use of hard chines which reduces build cost by not requiring excessive shell plate
bending. It was also initially thought that because the design was ice strengthened, using this
hull form would reduce hull modifications necessary for ice strengthening the Sea Tools tug.
This did not turn out to be true because ice strengthening the Sea Tools tug did not require hull
form modifications. The second hull form considered for a parent hull was a faired hull tug seen
in Figure 5. The advantage of choosing this form was that its dimensions were closer to the Sea
Tools tug target dimensions. This would reduce degradation of the hull form during parametric
transformation. Other advantages included favorable seakeeping characteristics and decreased
resistance at higher speeds.

17
Figure 4 - Double Hard Chine Hull Form – LOA
= 44.2 m
Figure 5 - Faired Hull Form –
LOA = 65.2 m
It was determined that the hard chine hull form was the best parent hull choice for the Sea Tools
tug. Breaking even financially after 15 years of operation was a driving requirement in our
design so a hull form which would reduce the initial build cost was an important factor in
choosing the hard chine hull. Also, most of the time, Sea Tools tugs will be towing at slower
speeds, so although the faired hull would reduce fuel costs by having decreased resistance at
higher speeds it was not a primary concern. Maxsurf was utilized to digitize the hard chine hull
form and parametrically transform it to the target dimensions found from the regression analysis.
For the capabilities the Sea Tools tug was going to be designed to perform, it was also
determined that the length of the work deck was too long and also that the displacement of the
hull at the design waterline was too large. The hull near the transom was truncated in order to
reduce the deck area and the displacement to just less than 3000 metric tons. The final hull form
has characteristics shown in Table 15.
Displacement (t) 2941
LOA (m) 66.8
LWL (m) 65.6
B (m) 15.0
D (m) 7.49
T (m) 5.63
C 0.52B
C 0.876X
C 0.836WP
LCB (m aft of FP) 49.93
LCF (m aft of FP) 35.99
KB (m) 3.55
Table 15 – Principal Dimensions and Hydrostatics
4.3 – Lines Drawing
The lines drawing for the Sea Tools tug hull form can be found in Appendix A. Station spacing
was decided and the lines plan was developed in Maxsurf. Table 16 contains the station spacing
used in the lines drawing.

18
Station Spacing (m) 5.14
Buttock Spacing (m) 1.08
Waterline Spacing (m) 2.95
Table 16 – Station Spacing

19
5.0 – Capabilities
The current design of the vessel is capable of undertaking many missions, ranging from routine
towing operations to oil recovery. The rules for specialized vessels under 90 meters in length
provided by the American Bureau of Shipping were considered when making all design
decisions. All machinery specifics are provided in Appendix G – Machinery Specifications.
5.1 – Salvage
The vessel was designed primarily to serve as a contract vessel for salvage missions. To be as
attractive a salvage vessel as possible, special attention was paid to the safe operation of the
vessel as well as cruising speed and machinery capabilities. Table 17 displays characteristics and
features of the vessel beneficial to salvage operations.
Speed 16 knots
Winch (aft) 208 mT
Winch (fore) 21.5 mT
Crane 35.7 mT
Table 17 – Salvage Characteristics
The capability of the vessel to cruise at 16 knots is a unique feature from other similar vessels
that enables the vessel to reach potential salvage sites quickly. An EBI Model TC-60 telescopic
boom crane will be installed just aft of the deckhouse on the starboard side of the vessel. In
addition to the characteristics listed in Table 17, weld and dive equipment will be stowed aboard
the vessel for use during salvage operations.
5.2 – Towing
The primary missions to be undertaken by the vessel will be barge towing, and as such the vessel
will be classified an A1 Towing Vessel by the American Bureau of Shipping. The characteristics
of the vessel at the target towing speeds of 3-7 knots were investigated and will be discussed in
detail later in this report. The specific winches selected were a 208 mT Markey TDSD-44, using
1018 m of 2.75 in thick wire rope for primary towing operations and a 21.5 mT Markey DEPC-
52, using 235 m of 10 in thick synthetic rope for ship assist situations. The TDSD-44 winch will
be located just aft of the deckhouse, and the DEPC-52 winch will be located on the forecastle
deck.
5.3 – Fire Fighting
Adequate fire fighting systems will be installed in the vessel to achieve A1 Fire Fighting Class 2
status from the American Bureau of Shipping. Four, Stang eight inch Electric Low Pro monitors
located on top of the deckhouse will be capable of 7200
𝑚𝑚3
ℎ𝑟𝑟
output as seen in Figure 6. In
addition to water dispensing capabilities, a foam mixing system will be utilized with the
minimum storage as listed below in Table 18. High expansion Silv-Ex Plus foam will be used in
cold weather fire fighting operations.

20
Figure 6 - Fire Monitor Location
Characteristic Proposed Design ABS Required
Number of Monitors 4 3 or 4
Discharge rate per Monitor 1800
𝑚𝑚3
ℎ𝑟𝑟
1,800
𝑚𝑚3
ℎ𝑟𝑟
Number of Pumps 2 2
Monitor Range 150 m 150
Monitor Height (at a distance 70 m from the vessel) 70 m 70 m
Foam Storage Capacity 6.35 m3
required
Table 18 – Firefighting Characteristics
5.4 – Oil Recovery
It was determined that instances in which oil pollution occurred were fairly common in the
operating region of the vessels. Currently the vessel is not planned to receive oil recovery
classification from the American Bureau of Shipping, yet oil recovery machinery will be
available in case of need. Two DESMI Tarantula oil skimmers with a capacity of 250
𝑚𝑚3
ℎ𝑟𝑟
as well
as two Canflex Sea Slug FCB-650CM towable bladders will be stowed below deck, accessible
with the crane. All machinery specification can be found in Appendix G – Machinery
Specifications.

21
6.0 – General Arrangements
The general arrangement for the salvage vessel was designed in Rhinoceros NERBs modeling
software, and the final result can be viewed in Figure 7. Its hull form was imported from
Maxsurf, and items were drawn such that dimensions, weight centers, and interferences could be
determined. The general arrangements can be found in Appendix C – General Arrangements.
Figure 7 - Interior General Arrangements
6.1 – Bulkhead Placement
The collision and after peak bulkheads were placed based on ABS under 90 m vessel
requirements. All bulkhead locations are presented in Table 19.
Station
(m)
Bulkhead Location
(m aft of FP)
Compartment
Length (m)
1 4.6 4.6
2 12.6 8.0
3 24.6 12.0
4 36.6 12.0
5 46.6 10.0
6 59.6 13.0
Table 19 – Bulkhead Locations
Figure 8 – Bulkhead Placement

22
6.2 – Floodable Length
The floodable length analysis performed on the Sea Tools tug ensured that the bulkheads placed
would permit one compartment flooding survival with a permeability of up to 0.95 while
remaining stable. There is no explicit governing criteria which specify compartment flooding for
uninspected tugs, however it was believed to be a smart design choice to pass one compartment
flooding. In addition to one compartment flooding, the front two compartments are capable of
being flooded without the vessel sinking. This was believed to be the most important two
compartment flooding case to be able to pass without adding an excessive amount of bulkheads
to the tug. The plotted results are presented in Figure 9 and in Appendix K.
Figure 9 – Floodable Length Analysis
6.3 Deck House
The arrangements of the tug were developed using the guidelines found within “Ship Manning
Trends in Northern Europe: Implications for American Shipowners and Naval Architects.”
Table 20 displays the requirements set forth by these guidelines and the actual accommodation
areas and characteristics. Some of the beneficial aspects of the vessel’s deckhouse are the use of
stairs only running fore and aft – conducive for periods of high roll motions – and
accommodations for the 12-man permanent crew, a 12-man salvaging crew, and 6 other
personnel if ever applicable.

23
Required Actual
Beds -- 30
Heads -- 24
Quarters 313.0 m
2
361.5 m
2
Galley 19.5 m
2
36.9 m
2
Dry Provision Stores 6.2 m
2
6.75 m
2
Refrigerated Stores 4.7 m
2
6.2 m
2
Mess Hall 26.4 m
2
32.2 m
2
Medical -- 27.9 m
2
Laundry 10.0 m
2
19.3 m
2
Workroom -- 52.1 m
2
Salvor Storage -- 27.9 m
2
Laboratory Space -- 51.3 m
2
Mapping/Charting 15.0 m
2
38.5 m
2
Wheelhouse 30.0 m
2
46.8 m
2
Table 20 - Deckhouse Accommodations
The lowest deck is positioned 2.69 meters above baseline. A drawing of this deck appears in
Appendix C – General Arrangements. On this deck all, main propulsion machinery, main
electrical powering machinery, and gearing can be accessed. The fuel tanks are located below
this deck while the potable and black/gray water tanks are situated on it. The bow thruster room
can also be accessed from this deck. The exhaust pipes from the engines and the fire monitor
pipes from fire pumps terminate, with only necessary jogs, above the deckhouse.
The deck 5.09 meters above baseline contains the lowest level of crew accommodations. Also
appearing on this deck is an HVAC/electrical cable trunk that terminates, without any jogs, in the
wheelhouse. A drawing of this deck appears in Appendix C – General Arrangements.
Main deck contains crew accommodations, workrooms, a salvor storage room, and a galley. The
workrooms are situated at the aft end of the deckhouse for the convenience of workers carrying
equipment inside from the work deck. Similarly, the medical center is located on main deck just
forward of the workrooms so an injured person can be moved from the work deck without
having to climb stairs. To minimize down-flooding points, the only door that can be used to
access the main deck portion of the deckhouse is situated on centerline. A drawing of main deck
appears in Appendix C – General Arrangements.
The 01 level houses officer accommodations, which are more spacious than the crew
accommodations. Exterior stairs can be used to access the 01 level from main deck. The crane
can also be accessed from the 01 level. The crane is used for lifting objects to and from docks
and deploying oil recovery equipment that is stored below main deck. While extended to 22.9
meters, the telescopic crane can lift 4.9 tons. The empty oil bladders onboard are 3.1 tons and
are held within the below deck storage 13 meters from the crane. Therefore, the crane can be

24
used to deploy the oil bladders. A drawing of the 01 level appears in Appendix C – General
Arrangements. The crane specifications appear in Appendix G – Machinery Specifications.
The 02 level holds laboratory space, which is used for analyzing oil samples and allows the
vessel to be used for research related missions in the future. Also appearing on the 02 level is a
space designated for charting and mapping. A drawing of the 02 level appears in Appendix C –
General Arrangements.
The wheelhouse is the highest enclosed deck of the deckhouse, and it contains navigational
equipment. The exhaust pipes terminate at the height of this deck, and the fire pipes continue to
the top of the deckhouse. A drawing of the wheelhouse appears in Appendix C – General
Arrangements.

25
7.0 – Propulsion and Powering
The rendering in Figure 10 – Propulsion System Rendering below illustrates the final design of the
propulsion system, hull form and all associated appendages on the vessel used in the following
section’s calculations.
Figure 10 – Propulsion System Rendering
7.1 – Resistance
The total vessel resistance was calculated in order to determine the resistive forces of the hull
and appendages at all plausible speeds. These values would later be used to calculate the speed
and available thrust of the vessel. Using HydroComp NavCad 2007, the vessel’s bare hull and
appendage drag were determined along with an eight percent preliminary design margin and
Table 21 illustrates the average percentage of drag associated with the hull and the appendages at
all speeds. NavCad allowed for all appendages to modeled, such as the skeg, Kort nozzles,
shafting, struts, bow thruster opening, ice knives and rudders. Predictive equations such as
Holtrop’s 1984 Method and the ITTC prediction line were also used. The plot in Figure 11
represents the total resistance and thrust of the vessel versus speed. The thrust of the vessel will
be further explained in the propulsion portion of this section. The intersection of the lines in this
plot indicates the operating point where vessel thrust equals vessel resistance and thus the
location of the vessel’s top speed of 16 knots.
Vessel Speed Bare Hull Drag (%) Appendage and Wind Drag (%)
2 - 16 knots 91% 9%
Table 21 - Percentage of Total Drag

26
Figure 11 - Total Resistance and Delivered Thrust versus Speed
7.2 – Prime Mover Selection
7.2.1 – Initial Point Design and Selection
The initial selection of the engines began with the owner’s requirement that a minimum of
10,000 hp be installed. Using this information, several engine manufacturers were investigated;
including Wärtsilä, Rolls Royce, and ElectroMotive. It was determined, based on our research,
that the ElectroMotive medium speed diesel engines were our best choice based on several
criteria. These criteria included the fact that they are two-cycle, easily maintained and reputable
engines that have been used on many tug boat applications. They currently retain an EPA tier
two marine certification and based on information received from a contact within EMD, it has
been indicated that with several easy, on board modifications that will soon be available, the
engines will be rated as tier three certified, which further increases the environmental
responsibility of the design. These engines also offer an instantaneous response in power when
altering throttle position, as well as a ten percent overload capability for two out of every twenty
four hours.
7.2.2 – Analysis of Selected Engines
Once the brand of engine was chosen, several configurations of engines were investigated in
order to meet the 10,000 hp minimum installed power. Everything from two large capacity
engines to four identical engines were investigated. The arrangement of one, sixteen and one,
eight cylinder ElectroMotive medium speed diesel engine per propeller shaft was selected,

27
delivering a total of 10,570 hp between all four engines. Table 22 and Table 23 illustrate the
characteristics of each selected engine. A detailed analysis of the fuel consumption of the
engines can be found in Appendix F – Powering Specifications. There is enough lube oil stored
on board to lubricate the prime movers for 3,360 hours of continuous operation in order to save
time at port when re-fueling the vessels.
Cylinders 8
Brand ElectroMotive
Table 22 – 8 Cylinder Engine Characteristics
Cylinders 16
Brand ElectroMotive
Table 23 – 16 Cylinder Engine Characteristics
Figure 12 illustrates the layout of the selected engines. The theory behind the layout displayed in
this rendered figure is so that the fire pumps can be powered mechanically with the two eight
cylinder engines, leaving the sixteen cylinder engines to provide propulsion power during fire
fighting exercises. Also, during towing of small barges or vessels or during general maneuvering
exercises where the entire 10,570 hp installed is not needed, the eight cylinders can be powered
down, reducing the overall fuel consumption and extending the life of the engines. This layout is
feasible by using a clutch system, along with the double input reduction gears going to the
propeller shafts, and the single reduction gears going to the fire pumps from the eight cylinder
engines. Appendix F – Powering Specifications contains more detailed information on these
engines.

28
Figure 12 - Engine Layout Rendering
7.3 – Propulsion Design
The propeller design in the particular case of a tug style vessel is fairly difficult because it is
necessary to maximize thrust at low speeds while also maximizing over all vessel speed for
quick response time to salvage operations. This was done using NavCad 2007 which led to the
design of two controllable pitch propellers housed within ka-19a Kort nozzles to maximize
thrust. Prediction equations such as Holtrop’s 1984 Method and Keller’s Cavitation equation
were utilized. The Kort nozzles and propeller shafting will be ice strengthened and protected by
ice knives on the back side for reverse conditions. The final characteristics of the counter rotating
propeller design are displayed in Table 24 and a rendering of the propeller design can be seen in
Figure 13.
Quantity 2
DP 4.0 m
P controllable
AE/AO 0.85
RPM 188 rpm
Table 24 – Propeller Characteristics

29
Figure 13 - Propeller and Kort Nozzles
The reason for the fairly low efficiency is due to the optimization of thrust and top speed. The
benefits of having one of these, causes downfalls to having the other. Figure 14 illustrates the
cavitation of the propeller blades at vessel speeds up to sixteen knots. It is relevant to note that at
low speed, towing and bollard pull condition, the cavitation is under 5%, thus lowering propeller
damage.
Figure 15 illustrates the propeller efficiency, torque and thrust coefficients. The propeller
efficiency is highest at thirteen knots, a typical port to port maneuvering speed.
Figure 14 - Cavitation versus Vessel Speed

30
Figure 15 - Propeller Coefficients versus Vessel Speed
7.4 – Towing and Bollard Pull
With the propulsion system preliminarily designed, its capabilities in towing and bollard pull
were explored in order to confirm that it was a feasible proposal. The missions of the tug, which
are reliant on the propulsion system, include salvage, barge towing and ship assist missions. It
was determined that our propulsion system delivered 129.7 tons force of bollard pull at the zero
speed condition, which was higher than the initial 115 tons force that was initially estimated.
To put this into a physical perspective, it was calculated that there was an available thrust of
roughly 789 kN at 7 knots. Analyzing the modern day 12,000 mT barge in Figure 16, with the
characteristics listed below, it was determined to have 615 kN of resistance from friction, wave
and wind drag terms. The available thrust is greater than the resistance of the barge, so Sea Tools
can confidently declare that this design is able to tow this typical barge with a 22% margin to
account for more adverse conditions. Appendix G – Machinery Specifications contains more
detailed information about this barge.

31
Figure 16 - 12,000 mt Barge (380' x 100') with 11' Draft
7.5 – Electrical Power Estimation
The electrical load of the design was initially estimated as the sum of the following machinery
and controls plus a twenty percent preliminary design margin: crane, winch, hotel/deckhouse
service, fire monitor controls, machinery pumps and controls, bow thruster, etc.
7.6 – Generator Selection
It is recommend that the installation of two 1,550 kW Caterpillar 3512C generators is reasonable
in order to design in redundancy in case of failure and to alternate between generators to increase
the life cycle of each. Also, these generators may both need to be used in situations involving
salvage operations and the use of the 500 kW bow thruster. The Caterpillar C6.6 ACERT
emergency generator was selected to ensure all communication and on board fire suppressant
systems are available in case of emergency or damage to the vessel or primary power generators.
The characteristics of the service loads versus installed generator power outputs are displayed in
Table 25. Appendix F – Powering Specifications contains more detailed information on these
generators.
Required (kW) Installed (kW)
Average at Sea Service Load 750 3,100
Maximum at Sea Service Load 1,525 3,100
Emergency Power 153 158
Table 25 – Generator Characteristics
7.7 – One Line Diagram
Figure 17 illustrates the electrical configuration on board the vessel and shows the availability of
440, 240 and 120 volt applications for select machinery and accommodations throughout the
vessel. This electrical design proposal allows for all current machinery to be operated efficiently,
as well as allowing for any future machinery additions to easily be installed. Appendix F –
Powering Specifications contains a larger detailed figure of the one line diagram.

32
Figure 17 - One-Line Diagram

33
8.0 – Intact and Damage Stability
Intact and damaged stability of the Sea Tools tug determined whether or not the ship was stable
enough to pass requirements set forth in the Code of Federal Regulations (CFR).
8.1 – Intact Stability
Intact stability of the vessel was analyzed using the HECSALV stability suite and compared to
CFR requirements.
8.1.1 – U.S. Coast Guard Wind Heel Requirements
The U.S. Coast Guard requires a minimum GMT based on a ship’s profile area above water on
which beam winds could act and heel the ship. The “USCG Wind Heel GMT” spreadsheet was
used to determine minimum value to be 0.62 m. The Sea Tools tug’s GMT is 3.19 m, which
clearly passes this requirement. The “USCG Wind Heel GMT” spreadsheet has been included in
Appendix J – Intact Stability.
8.1.2 – Towing Stability Criteria
The CFR mandates certain stability requirements in the towing condition. A choice is given in
the CFR of meeting a minimum metacentric height (GM) or passing requirements regarding the
heeling arm and righting arm curves. The GM height requirement was chosen as the towing
stability criterion the Sea Tools tug was to pass. The equation found in Figure 18 is provided and
the indicated inputs were used to calculate the minimum required GM. The equation derives
from the tug having its rudders full turned at full speed while not moving forward which creates
the largest heeling moment on the tug.
2
3
f
( )( ) ( )( )
( )B
N P D s h
GM
K
×
=
∆
N (number of propellers) 2
P (shaft power per shaft in kilowatts) 3941
D (propeller diameter in meters). 4.5
s (fraction of the propeller circle cylinder intercepted when rudder
turned 45 degrees from the vessel's centerline)
0.719857
h (vertical distance from propeller shaft centerline at rudder to
towing bitts in meters)
6.83
Δ (displacement in metric tons) 2936
f (minimum freeboard along the length of the vessel in meters) 1.859
B (molded beam in meters) 15
K=13.93 in metric units 13.93
Figure 18 - Towline Pull Criterion
The calculated minimum GM requirement for the Sea Tools tug was discovered to be 1.32 m.
The Sea Tools tug’s GMT of 3.19 m passes this requirement.
8.1.3 – Topside Icing
Specific requirements regarding icing of the topsides of an uninspected tug do not exist however
this was a case that Sea Tools wished to consider for the tug because of its Arctic operation. The
CFR topside icing requirements for fishing vessels was used to calculate the effects of icing on
the Sea Tools tug. The icing requirements are applicable for vessels operating between 42˚

34
North latitude and 66˚30’ North latitude between November 15 and April 15. 30 kg/m2
(corresponding to 1.3”) of ice and 15 kg/m2
(corresponding to 0.65”) of ice is to be used for
horizontally and vertically projected surfaces, respectively. This calculation indicated that full
topside icing would result in 15.7 mt of ice added to the vessel. Adding this mass to our weights
estimation and recalculating the hydrostatics determined that the GMT of the vessel reduces to
3.16 m, which still passes all of the CFR mandated requirements.
8.1.4 – Cross Curves of Stability
HECSALV was used to generate the cross curves of stability for the Sea Tools tug and then used
to create the GZ curves at the full load condition. The GZ curves are presented in Figure 19.
The max GZ of 1.22 m occurs at a heel angle of 34.9˚.
Figure 19 – GZ Curves
8.1.5 – Bonjean Curves
Bonjean curves present station areas at different mean drafts. HECSALV was used to generate
these curves and are presented in Figure 20.
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0 20 40 60 80 100
GZ(m)
Heel Angle (deg)
GZ Curve Max GZ

35
Figure 20 – Bonjean Curves
8.2 – Damaged Stability
Requirements governing compartment flooding survival for uninspected tugs does not exist,
however safe operation in damaged conditions was a primary concern for the Sea Tools tug
design. One compartment flooding for all compartments was determined to be a necessary
requirement in addition to two compartment flooding in the two bow compartments. The
MARAD Design Letter 3 was used as damaged stability to determine if the Sea Tools tug would
remain stable in each damaged condition. These criteria were selected because they are
relatively conservative compared to other rule sets which could have been used for this vessel.
The rules are presented in Table 26.
GZ Max Heel GM
20˚ positive range, 0.1 m minimum 15˚ Positive
Table 26 - MARAD Design Letter 3 Damaged Stability Criterion
The Damaged Stability part of the HECSALV program suite was used to test eight different
compartment flooding cases. Initially, the tug failed when the engine room was flooded. The
bulkheads were re-spaced to decrease the volume of the engine room. Compartment one is the
forward most compartment on the vessel. A summary of each damage stability case is shown in
Table 27. All of the damaged cases with their complete results and diagrams are included in
Appendix K – Damaged Stability.

36
Damaged Equilibrium
# Draft Status Damage
AngMax
GZ (deg)
IntGM
(m)
Area
(m-rad)
LimitAngle
(deg)
AngE
(deg)
MaxGZ
M
Range
(deg)
Pass/Fail
1 1 1 1 15.3 0.308 0.0215 22.9 0 0.100 22.9 Pass
2 1 1 2 12.9 0.519 0.0231 21.4 0 0.100 21.4 Pass
3 1 1 4 10.8 0.792 0.0231 20.6 0 0.100 20.6 Pass
4 1 1 8 10.0 1.073 0.0288 20.0 0 0.134 20.0 Pass
5 1 1 10 9.9 1.296 0.0348 20.0 0 0.164 20.0 Pass
6 1 1 12 10.5 0.822 0.0234 20.0 0 0.107 20.0 Pass
7 1 1 13 14.7 0.343 0.0202 21.5 0 0.100 21.5 Pass
8 1 1 1,2 11.9 0.577 0.0226 20.7 0 0.100 20.7 Pass
Table 27 – Damage Stability Results

37
The midship cross section of the vessel was structurally analyzed to determine if the ship passes
the regulations set forth by the American Bureau of Shipping (ABS).
9.1 – ABS Regulations
ABS regulations state that the section modulus of the midship section should be larger than the
greater result of equations one and three. The equations used to calculate the requirements are
provided below.
2
min 1 2 ( 0.7)bSM C C L B C= + Equation 1
1 0.0451 3.65C L= + Equation 2
2 0.01C = Equation 3
/t pSM M f= Equation 4
t SW WSM M M= + Equation 5
Maximum Still Water Bending MomentSWM = Equation 6
2 3
1 1 ( 0.7) 10WS bM k C L B C −
=− + ⋅ Equation 7
2 3
2 1 10WH bM k C L BC −
= ⋅ Equation 8
1 110k = Equation 9
2 190k = Equation 10
2
17.5 /pf t cm= Equation 11
The results from these calculations are listed in Table 28. These values were used in the analysis
of the midship section.
Variable Result Units
Mws -56,000 kN-m
Mwh 44,650 kN-m
Msw 31.41 kN-m
SMmin 3202.0 cm2
-m
SM 16,390 cm2
-m
Table 28 – ABS Longitudinal Strength Calculations
9.2 – Moment and Shear Diagram
The moment and shear diagrams were generated using Hydromax. The weights curves were used
in previously described calculations to confirm that the vessel adhered to ABS regulation. The
maximum bending moments are presented in Table 29.
Condition Max Moment
Full Departure 3689 mt-m
%50 Fuel 3110 mt-m
%10 Fuel 3270 mt-m
Table 29 - Maximum Bending Moments

38
The maximum bending moment was developed in the Full Departure condition and using
Hydromax, the net load, shear, and bending moment distributions were plotted. The complete
results from Hydromax are included in Appendix M – Structural Calculations as well as the
weights estimation spreadsheets.
Figure 21 – Load Distribution for the Full Load Condition
The utilization of a midship section analysis spreadsheet was used in conjunction with the
section modulus and moment of inertia values calculated from the ABS requirements to
determine the characteristics of the vessel’s midship section. Because of how the vessel was
strengthened, the minimum SM requirement of 3,202 cm2
-m was met easily. This spreadsheet is
included in Appendix M – Structural Calculations and a table of the midship section properties is
included in Table 30.
ABS Required Actual Units
SM deck 3202 29,220 cm2
-m
SM bottom 3202 16,390 cm2
-m
Table 30 – Midship Section Strength Properties

39
10.0 Structural Analysis
The structural analysis of the vessel was performed considering two regulatory sources of input.
While the vessel will be classified by the American Bureau of Shipping, all Ice strengthening
aspects of the vessel were designed considering the “Finnish-Swedish Ice Class Rules”. These
rules were selected based on their relative strictness when compared to ABS, and the structural
safety they will provide. Rules from the American Bureau of Shipping found in “Rules for
Building and Classing Steel Vessel Under 90 Meters in Length” were referenced for all other
aspects of the design. A summary of plate thicknesses can be found below.
10.1 Ice Strengthened Regions
The Finnish-Swedish ice class rules designate four possible classification of ice class: 1C, 1B,
1A, and 1A super. The current design of the vessel adheres to rules for Ice Class 1A vessels. The
ice belt region of the vessel was determined using the following equation table the Finnish-
Swedish Ice Class rules.
Ice Class Extension Above LWL (m) Extension Below LWL (m)
1A Super 0.6 0.75
1A 0.5 0.6
1B 0.4 0.5
1C 0.4 0.5
Table 31 – Ice Belt Definitions
While the vessel is designed to meet Ice Class 1A requirements in the ice belt region, the ice belt
of the vessel extends 0.6 m above and 0.75 m below the design water line, which is only required
of Ice Class 1A Super vessels. The thickness of plate in the ice belt is higher (25.4 mm) than the
rest of the side shell (16 mm). Further ice strengthening measures were implemented in the
framing of the vessel.
Plate Location Thickness (mm)
Bottom Shell 16
Side Shell 16
Side Shell – Ice Belt 25.4
Bulwarks 16
Main Deck 25.4
Bulkheads 16
Deckhouse – Sides/Decks 8
Fuel Tank Tops/Below Decks 8
Table 32 – Plating Thicknesses

40
10.2 Framing
Transverse framing was selected for the vessel because of its relatively short length and the
simplicity of construction that transverse framing offers. Unless stated otherwise, all framing in
the vessel was spaced at 0.46 m. This section will discuss the structural members of each part of
the vessel. All structural calculations can be found in Appendix M – Structural Calculations.
Location
Classification
Society Used
Required SM
(m*cm2
)
Actual SM
(m*cm2
)
Bottom Frame ABS 1018 1140
Side Frame FIN 1133 1140
Deck Frames ABS 702 747
Deck Girders ABS 4162 4553
Bulkhead Girder ABS 69 87
Bulkhead Stiffener ABS 328 352
Superstructures - Side ABS 26 38
Superstructure – Deck Frames ABS 696 761
Superstructure – Deck Girder ABS 515 564
Table 33 – Required and Actual Section Moduli
Angle bars were used as stiffening members in all locations except the deckhouse. Angle bars
were selected over t-bars because of lower cost and ease of production. In the deckhouse of the
vessel it was feasible to select unobtrusive flat plate bars with an adequate section modulus. In
future design iterations the sizing of these bars will be investigated with special attention paid to
the weight of flat bar stiffeners and the space that could be saved if angle or t-bars were selected
instead.
Location L (cm) W (cm) t (cm) Steel Strength
Bottom Frame 20 20 3 Normal
Side Frame 20 20 3 High
Deck Frames 20 15 2.5 Normal
Deck Girders 71 56 2.5 Normal
Bulkhead Girder 8 8 1 Normal
Bulkhead Stiffener 15 15 1 Normal
Superstructures - Side 10 --- 1 Normal
Superstructure –Deck Frames 20 15 2 Normal
Superstructure –Deck Girder 40 --- 2.5 Normal
Table 34 – Stiffener Sizing
The bottom and side frames of the vessel have the largest required section moduli of all
structural members below deck. Because of the similar nature of the bottom and side framing
requirements, angle bars with identical geometry were selected for these structural members. It
should be noted that the side frame requirement assumes that the frames be constructed out of a

41
high strength steel of yield stress greater than 315
𝑁𝑁
𝑚𝑚 𝑚𝑚2
. Because the side frames of the vessel
will be constructed out of high strength steel, longitudinal strengthening members will not be
necessary on the side shell. Another benefit of using such structurally sound side frames is that
machinery stress, such as moments generated by the winches or crane, will not cause the failure
of any structural members.
The bulkheads of the vessel will also be structurally sound. All bulkheads will be constructed out
of 16 mm thick steel and fitted with vertical stiffeners sized to adequately strengthen the deepest
bulkhead of the vessel. Where necessary, a horizontal deck girder will be installed such that no
vertical span of length 4.5 m or more will be horizontally unsupported. The deep tank structural
requirements were also analyzed. It was determined that the existing bulkhead plating and
stiffeners would adequately strengthen the deep tanks, and that no additional structural members
would be required.
The deck of the vessel will be made out of inch thick steel and strengthened by both transverse
deck frames and two longitudinal deck girders spaced evenly across the deck. The high section
modulus requirement of the longitudinal deck girders is a result of the bulkhead spacing of the
vessel. Two deck girders were selected to reduce the sizing requirements of the transverse deck
frames. The size of the deckhouse necessitated that the transverse deck frames in the deckhouse
be sized similarly to the deck frames of the main deck. These deck frames were joined to
relatively small deckhouse side frames to complete the deckhouse framing system. As previously
discussed, a flat bar longitudinal deck girder was fitted below each deck level, and the geometry
of this girder will be investigated in the future.

42
11.0 – Maneuvering Analysis
The University of Michigan’s Maneuvering Prediction Program (MPP) was used to determine
the maneuvering characteristics of the Sea Tools tug and to size its rudders.
11.1 – Initial Sizing
MPP requires an initial guess for the size of the rudder and iterations must be performed to meet
IMO maneuvering regulations. The initial input for the size of one rudder was derived from the
equation below.
Equation 12
The estimated rudder area was calculated to be 8.5 m2
.
11.2 – Maneuvering Prediction Program
Several iterations were necessary to find an appropriate rudder size. The final rudder area was
determined to be 11.1 m2
. For a rudder turning ability of 35˚, a ship is specified to have an
advance of less than 4.5LBP, a tactical diameter of less than 5LBP, a Clarke’s turning index
greater than 0.4, and a Linear Dynamic Stability Criterion greater than zero. The maneuvering
requirements and results for the tug are presented in Table 35. Results from MPP are provided in
Appendix H – Maneuvering.
Required Calculated
Advance (m) <295.2 236.1
Tactical Diameter (m) <328 312.8
Clarke’s Turning Index >0.4 11.3
Linear Dynamic Stability >0.0 0.00041
Table 35 – Maneuvering Analysis
11.3 – Bow Thruster
The bow thruster for the Sea Tools tug was selected by performing a regression analysis on
similar tugs and their projected sail area (Figure 22). Based on the Sea Tools tug’s sail area of
325 m2
, it was determined that the bow thruster should have an installed power of 502 kW
(including a 20% margin). A 614 kW Wartsila and 530 kW Schottel bow thruster were both
examined for selection. The Schottel thruster was chosen because its power was closer to the
estimated power requirement and because of lower weight and therefore lower expected cost.
Thruster details are provided in Appendix H – Maneuvering.
2
1 25
100
r
LT B
A
L
  
= +     

43
Figure 22 - Bow Thruster Regression
y = 1.8373x - 178.64
R² = 0.9916
0
200
400
600
800
1000
1200
1400
1600
0 200 400 600 800 1000
TotalInstalledThrusterPower(kW)
Windage Area (m2)
Installed Thruster Power vs. Windage Area

44
12.0 – Seakeeping Analysis
Seakeeper was used to perform a seakeeping analysis on the Sea Tools tug in sea states four,
five, and six. The tug will be operating in the Bearing Sea, the Gulf of Alaska, and the western
coast of Canada and the USA thus an appropriate wave spectrum was selected to model the
conditions there. The ITTC 2 Parameter Bretschneider wave spectrum was used and the
characteristic conditions can be seen in Table 36.
Sea State Wave Height (m) Average Period (s) Wind Speed (kn) Probability (%)
4 1.88 8.80 19.00 31.6
5 3.25 9.70 24.00 20.94
6 5.00 12.40 37.50 15.03
Table 36 - North Pacific Sea State Characteristics
Wave headings from 0 to 180 degrees were examined in increments of 10 degrees. 180 degrees
represents waves following seas, 90 degrees represents beam seas, and 0 degrees represents head
seas. Speeds of 0 kn, 5 kn, 10 kn, and 16 kn were analyzed.
12.1 – Seakeeper Results
The first step in analyzing the seakeeping results from Seakeeper was to verify the response
amplitude operators (RAOs) were making sense for all specified headings and speeds. All we
checked and their shapes and amplitudes did make sense for all headings and speeds. A
sampling of the RAOs at 16 kn can be seen in Figure 23 - Figure 27. One interesting point that
would require additional investigation in further design iterations is the peak amplitude in heave
exceeding the pitch peak amplitude in Figure 25 - Figure 27. This was not expected and is only
seen at these headings at 16 kn and not at other headings or speeds. This is expected to be a
result of the tug’s hull having a low block coefficient while being a “beamy” ship (small L/B
ratio).
Figure 23 - 16 kn RAO, 0º Figure 24 - 16 kn RAO, 30º
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 1 2 3
RAO(TransferFunction)
Encounter Frequency (rad/s)
0˚ - Following Seas
Heave RAO Roll RAO Pitch RAO
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 1 2 3
30˚

45
Figure 25 - 16 kn RAO, 90º Figure 26 - 16 kn RAO, 140º
Figure 27 - 16 kn RAO, 180º
The next step in analyzing the Seakeeper data was to examine the RMS values of heave, roll, and
pitch at all headings, speeds, and sea states. Plots of the RMS heave, roll, and pitch values at 16
kn are presented in Figure 28, Figure 29, and Figure 30. It was seen that the motions appear as
expected for the given sea state and heading and it should be noted that the consistency of data
was also verified at the other speeds analyzed. Subsequent design iterations should use an
alternative seakeeping analysis to verify the results found here. The complete Seakeeper results
are included in Appendix L – Seakeeping Results.
0
0.5
1
1.5
2
2.5
3
0 1 2 3
90˚ - Beam Seas
0
0.5
1
1.5
2
0 1 2 3
140˚
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 1 2 3
180˚ - Head Seas

46
Figure 28 - Heave Response
Figure 29 - Roll Response
Figure 30 - Pitch Response
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 50 100 150 200
HeaveAmplitude(m)
Heading (deg)
Heave RMS, 16 kts ss4 ss5 ss6
0
1
2
3
4
5
6
7
8
0 50 100 150 200
RollAmplitude(deg)
Heading (deg)
Roll RMS, 16 kts ss4 ss5 ss6
0
0.5
1
1.5
2
2.5
3
3.5
0 50 100 150 200
RollAmplitude(deg)
Heading (deg)
Pitch RMS, 16 kts ss4 ss5 ss6

47
12.2 – Natural Periods
The RAO graphs produced by Seakeeper were analyzed and the natural frequencies found for
each response. The natural periods for each response were then found and are listed in Table 37.
Degree of Freedom Natural Period (s)
Heave 5.7
Roll 6.3
Pitch 10.1
Table 37 - Natural Periods
12.3 – Working Condition Analysis
The specified owner’s requirements dictated that the tug be able to operate in sea state six and at
the full speed of 16 kn. In order to validate workable conditions on the tug boat, it was necessary
to look at the Motion Induced Interruptions (MIIs) occurring at critical locations on the vessel.
The red markers seen in Figure 31 show the two locations analyzed, the wheel house on
centerline and the tow winch controls, 3 m starboard of centerline.
Figure 31 - Critical MII Locations
Seakeeper calculates the accelerations at those locations and determines how many times per
hour a person would be interrupted during their work due to the local accelerations. All speeds
and headings were analyzed and the worst MII cases are shown in Table 38.
Motion-Induced Interruptions per hour
SS4 SS5 SS6
Wheelhouse 5.6 18.0 16.5
Work deck 8.2 19.4 18.3
Table 38 - Worst Cast MII Results
As highlighted in red, the maximum number of MIIs per hour is about 20, which falls between
the lowest two severity ranges shown in Table 39. From this analysis, it has been determined

48
that a salvage crew will have no problem operating the Sea Tools tug at full speed during sea
state six.
MII Risk Levels
Severity MII Risk Level MII per hour
1 Possible 6
2 Probable 30
3 Serious 90
4 Severe 180
5 Extreme 300
Table 39 – MII Risk Levels
The Motion Sickness Incidence analysis performed by Seakeeper did indicate that an untrained,
non-sailor would be subject to 10% probability of sea sickness in under 30 minutes during sea
states five and six at a full speed of 16 kn. However, contacts in the U.S. Coast Guard have
indicated that this will not be an issue for a seasoned salvage tug crew.

49
13.0 – Fleet Justification
A solution was sought for the owner’s requirements set forth by the MARAD/SNAME student
design competition. These requirements included operating near the Aleutian Island chain,
having the ability to perform salvaging operations, and possessing an expense break even period
of no more than 15 years.
First, the demand for a salvage tug operating near the Aleutian Islands was investigated. Data
collected from the USCG Marine Safety Management System and the Marine Information Safety
and Law Enforcement System were reviewed. These data included the vessel types involved in
incidents and the type of incident for accidents occurring near the Aleutian Islands from 1991-
2003. The per-year averages for types of incidents and types of vessels during this time period
were calculated. These averages are shown in Table 40.
Vessel Types Per Year Incident Types Per Year
Fishing Vessels 229 Pollution 113
Freight Ships 19 Person 94
Commercial Vessels 12 Vessel 59
OSVs 9 Facility 3
Table 40 - Incidents near the Aleutian Island
It was noted that fishing vessels and OSVs were comparable in size to the salvage tug to be
designed and therefore would not be an economically viable source . However, on average there
were over 30 incidents per year involving freight ships and commercial vessels. It was also
noted that pollution was the most frequently occurring incident type.
After verifying the demand for salvage support in the Aleutian Islands and Gulf of Alaska, a
mission model was devised. A fleet of three tugs was chosen to operate out of the cities of Dutch
Harbor, AK; Juneau, AK; and Seattle, WA. All vessels would have the same design and
capabilities. Dutch Harbor was chosen due to its proximity to the Unimak Pass – a waterway
passage heavy with commercial shipping traffic. The Dutch Harbor tug was designated as solely
a salvaging vessel. It was decided that the Juneau and Seattle tugs would perform towing
operations between the two cities as a commercial source of income. These two vessels would
alternate travelling from Seattle to Juneau. With one tug towing a barge and the other
commuting back to Seattle, a constant source of commercial income would be obtained while
still maintaining the ability to attend to salvaging incidents. Port Hardy, British Columbia and
Prince Rupert, British Columbia were ports chosen as barge drop off locations in the event that a
tug engaged in towing was called for emergency related operations.
The locations of the three tugs are shown in Figure 32. Also, with the possibility of response
time being key in an emergency, red and yellow circles are shown to indicate distances
accessible after 24 and 36 hours of travel at the design speed of 16 knots.

50
Figure 32 - Tug Fleet Locations

51
14.0 Economic Analysis
The economics of the tug fleet were analyzed and refined throughout the design of the vessel.
With the 15-year break even requirement driving the analysis, the expenses incurred from crew
costs, build costs, and operational costs were examined. Through a contact within the salvaging
industry, estimates for 12-man crew costs were provided. These crew costs appear in Table 41.
Crew Cost Per Day Crew Cost Per Year Crew Cost Over 15 years
Captain $650 $237,250 $3,558,750
Mates (3) $1,620 $591,300 $8,869,500
Chief Engineer $550 $200,750 $3,011,250
QMEDs (2) $800 $292,000 $4,380,000
AB Deckhands (5) $1,550 $565,750 $8,486,250
25% Payroll Tax $1,293 $471,763 $7,076,438
15% Admin Expense $776 $283,058 $4,245,863
Total Crew Costs $7,238 $2,641,870 $39,628,050
Table 41 - Crew Cost Breakdown
The contact also provided a build cost estimate of $20 million. To make this estimate more
conservative, it was increased to $25 million. In addition, an 80% loan with a 4% interest rate
compounded annually for 15 years was applied to the $25 million build cost estimate. These
figures, as well as the accumulated interest and total build cost, are presented in Table 42.
Build Cost
Build Cost $25,000,000
80% Build Cost Loan $20,000,000
Interest Rate 4%
Accumulated Interest $1,798,822
Total Build Cost $26,798,822
Table 42 - Build Cost Breakdown
Lastly, a preliminary estimate for the operational costs was provided by the industry contact.
These costs are displayed in Table 43.
Per Day Per Year Over 15 Years
Operational Costs $4,762 $1,738,130 $26,071,950
Table 43 - Operational Cost Breakdown
The total preliminary costs for the tug design and the three tug fleet over the first 15 years of
operation are presented in Table 44.
15 Year Expense Totals
15 Year Total Tug Expenses $92,498,822
15 Year Total Fleet Expenses $277,496,466
Table 44 - 15 Year Expense Summary

52
With the preliminary expenses established, estimates were made for the possible returns through
salvaging operations, fire fighting, and other emergency related missions. The industry contact
estimated that a gross income of $8 million can be received from a single large salvaging job. A
more conservative estimate of $5 million per salvage job each year per tug was used. Based off
of this estimate, the returns used for the preliminary economics of the tug fleet appear in Table
45.
Per Year Over 15 Years
Dutch Harbor $5 million $75 million
Juneau $5 million $75 million
Seattle $5 million $75 million
Total $15 million $225 million
Table 45 - Salvage Revenue
Throughout the design, as machinery was selected and the missions to be performed were
developed further, the economic analysis of the fleet was refined. The same estimates used for
the preliminary twelve man crew and build costs were used for the additional iterations of the
economic analysis. Using specific fuel consumptions, average fuel prices, and time at sea
estimates, the operational costs were updated. The specific fuel consumptions used appear in
Table 46, and the average fuel prices, collected by the Fisheries Economics Data Program, are
shown in Table 47.
8 Cylinder 16 Cylinder
SFC (lb/bhp-hr) 0.336 0.3275
Consumption Rate (lb/hr) 554.4 1195.4
Volume Consumption Rate (gal/day) 1874.03 4040.70
Table 46 - Specific Fuel Consumption
#2 Marine Diesel Fuel Prices
2010 Average Alaskan Port Fuel Prices $2.91
2010 Average Washington Port Fuel Prices $2.65
Average of 2010 Alaskan and Washington Port Fuel Prices $2.78
Table 47 - Average Fuel Prices
These data were combined with time at sea estimates. The time at sea estimates were developed
by considering that the Dutch Harbor tug would not tow and would, therefore, spend less time at
sea per year. While operating at sea, it was assumed that all four of a tug’s engines would be
operating at 850 rpm. In addition, the average 2010 port fuel prices for #2 marine diesel fuel in
Alaska and Washington were averaged for the Juneau and Seattle tugs. This was done because
the tugs would be towing between the two states and might refuel in either Alaska or
Washington. The fuel consumption summaries for each tug appear in Table 48, Table 49 and
Table 50.

53
Dutch Harbor
Time At Sea (Days) 28
Fuel Consumed Per Year (Gallons) 331,225.01
Fuel Cost Per Year $963,864.79
15 Year Fuel Cost Total $14,457,971.86
Table 48 - Dutch Harbor Fuel Cost
Seattle
Fuel Consumed Per Year (Gallons) 3,395,056.39
Fuel Cost Per Year $9,438,256.78
Table 49 - Seattle Fuel Cost
Juneau
Fuel Consumed Per Year (Gallons) 3,395,056.39
Fuel Cost Per Year $9,438,256.78
Table 50 - Juneau Fuel Cost
The refinement of the operational costs caused the total 15 year fleet cost to increase to
$496,886,291. Using the same salvaging and firefighting return estimates as the previous
economic iteration, it was calculated that the residual returns needed to be made from towing, in
order to break even within 15 years, was $271,886,291. These figures are displayed in Table 51.
15 Year Expense and Return Totals
Total 15 Year Fleet Expenses $496,886,291
Total 15 Year Salvaging Returns $225,000,000
Necessary 15 Year Towing Returns $271,886,291
Table 51 - Required Returns
The time necessary to tow a barge from Seattle to Juneau was investigated by determining how
quickly a barge could be towed and by determining how much time should be given to stay in
port for fuel, water, and provisions. The time required for a tug to make a roundtrip was
calculated by allowing one day for the vessel to prepare for the trip in Seattle, tow a barge at an
average of 6 knots to Juneau, spend one day idle in Juneau for fuel, water, and provisions, and
traverse back to Seattle at 16 knots. The total time required for this roundtrip is 9.4 days. The
total amount of trips possible over 15 years between two tugs was then calculated, followed by
the amount of money required to charge per tow to make approximately $272 million from
towing – the amount necessary for the fleet to make to break even within 15 years. These figures
are presented in Table 52.

54
Towing
Days Per Trip 9.4
Trips Per Year 39
Trips Over 15 Years (2 Tugs) 1165
Required Charge Per Tow $233,379
Total Towing Gains $271,886,291
Table 52 - Towing Summary
The required freight rates of a variety of barge sizes appear in Table 53. These rates are
required, in order to break even within 15 years of operating the fleet, due to losses incurred
from building, operating, and manning the tugs.
RFR 4000 ton barge $58.34/ton
Table 53 - Required Freight Rate

55
15.0 – Recommendations for Future Work
While all design decisions were well-informed and made with confidence, there are some areas
of the design that warrant future investigation. These areas are discussed in the body of the report
as they occur, and this section will detail recommendations for future work.
One area of potential concern is the ease of deep tank production. Future design iterations will
investigate alternate fuel tank arrangements that would allow for easier welding during
construction. The seakeeping analysis of the vessel is another area that deserves future
investigation. The data obtained from Seakeeper will need future validation by other methods,
and special attention will be paid to why the heave RAOs are dominating pitch RAOs at 16 knots
in sea state 6 at headings between head and beam seas. A seakeeping analysis with a towing
barge attached will also be necessary.
The propulsion system of the vessel could be improved in the future by performing more
iterations of the propeller design to maximize, thrust, speed, and efficiency. Once completed, the
system could be analyzed further and its capabilities in towing and bollard pull. It is in the
opinion of Sea Tools that these further iterations will decrease the preliminary design margins
and increase the towing ability of the vessel as well as the static bollard pull characteristics of the
vessel. Future design iterations should also address the piping and electrical requirements for all
areas of habitability. Adjustments to the arrangements may need to be made to minimize piping
and electrical material in these areas. Also, more detailed estimations should be found for the
returns to be made through salvaging, fire fighting, and other emergency missions. Lastly,
pricing of machinery and outfitting should be considered for a more accurate build cost.

56
16.0 – Conclusion
Not only does the Sea Tools tug design satisfy all of the MARAD/SNAME student design
competition requirements but also has a wide range of towing and rescue capabilities, making it a
versatile design. Sea Tools Engineering is confident that the design will satisfy the need for high
powered salvage tugs near the Aleutian Islands and the Gulf of Alaska. Key features of the
design include highly favorable seakeeping properties, fire fighting II capabilities, and an ice
strengthened hull, all of which allow the vessel to perform commercial and rescue missions in a
variety of arctic water conditions.

57
Appendix A – Lines Drawing
Contents:
Lines Drawing........................................................................................................................A-1

58
Appendix B – Outboard & Inboard Profiles
Contents:
Outboard Profile.....................................................................................................................B-1
Inboard Profile .......................................................................................................................B-2

59
Appendix C – General Arrangements
Contents:
General Arrangements 1 ........................................................................................................C-1

60
Appendix D – Propeller Geometry
Contents:
Propeller.................................................................................................................................D-1

61
Appendix E – Structural Drawings
Contents:
Deckhouse Section Layout ....................................................................................................E-1
Bulkhead Section Layout.......................................................................................................E-2
Midship Section Layout.........................................................................................................E-3

62
Appendix F – Powering Specifications
Contents:
EMD Brochure.......................................................................................................................F-1
8 Cylinder Fuel Consumption................................................................................................F-2
16 Cylinder Fuel Consumption..............................................................................................F-3
Caterpillar 3512C Genset.......................................................................................................F-4
Caterpillar C6.6 ACERT Emergency Generator ...................................................................F-5
One Line Diagram..................................................................................................................F-6

C
M
Y
CM
MY
CY
CMY
K
PMI brochure_outside.pdf 9/10/07 10:09:15 AM

C
M
Y
CM
MY
CY
CMY
K
PMI brochure_inside.pdf 9/10/07 10:03:44 AM

Fuel Consumption
Model: 8-710G7C-T2
Conditions: ISO 15550 & 3046-1 Standard Reference Operating Speed: Variable
Air In Temp: 77o
F (25o
C) Load: Variable
Barometer: 29.61 in Hg (100 kpa) Rated Speed: 900 RPM
Fuel S. G.: 0.855 (7.1 lbs/gal) Idle Speed: 350 RPM
Fuel LHV: 18360 btu/lb (42700 kJ/kg) ISO Continuous Power: 2000 BHP
Airbox Temp: 120o
F (49o
C) maximum ISO Overload Power: 2200 BHP
BSFC Tolerance: + 5% maximum Emissions: US EPA 40 CFR 94
Emissions Tier: 2
Application: Fixed Pitch Prop Propulsion EPA Duty Cycle Table: B-1
ISO Cycle: E3
Comments:
Engine mounted pumps included.
Horsepower / fuel consumption will vary with deviation from stated conditions.
Data is provided in accordance with ISO 3046-1:2002E conditions and associated tolerances, and is intended only
for purpose of comparison with competitive manufacturer engines.
Electro-Motive Diesel, Inc. maintains ISO9001:CURRENT REVISION registration for its engine manufacturing and
test facilities. Factory engine test data is recorded at observed site conditions in accordance with
ISO9001/QMS9000 procedures.
0.330
0.340
0.350
0.360
0.370
0.380
0.390
0.400
0.410
0.420
0.430
0.440
0.450
0.460
0.470
0.480
0.490
0.500
0.510
0.520
0.530
300 400 500 600 700 800 900
Engine Speed (rpm)
FuelConsumption(lb/bhp-hr)
100
300
500
700
900
1100
1300
1500
1700
1900
2100
EnginePower(bhp)
Commercial_8G7C-T2_VS9_VL_B-1_E3.xls

Marine Propulsion Engines
3500C

More available power over a wider
operating range
High power density for continuous applications with A and B
ratings at 1200, 1600, and 1800 rpm.
More sophisticated electronic
control system
Provides improved engine monitoring, communication, and
display capabilities. Results in easier integration with your
vessel’s systems.
More flexible cooling system
options
Separate Circuit Cooling for optimum cooling capabilities. Keel
cooled options are designed for high inlet water temperatures,
minimizing cooler size and installation costs.
Durable and reliable
The 3500 engine platform is a simple and proven design providing
industry-leading reliability and durability.
True technical sophistication
Delivers ease of maintenance and assembly/disassembly without
the need for expensive processes or tools.
Meets EPA Tier 2 Marine,
EU Stage IIIA and IMO
emissions regulations
the sophistication
of simplicity
New Diesel
Electric Propulsion
ratings available
2250 ekW 3516-HD @ 60Hz
2000 ekW 3516-HD @ 60Hz

SeniorDesignProjectReport

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (19)

Similar to SeniorDesignProjectReport

Similar to SeniorDesignProjectReport (20)

SeniorDesignProjectReport