1. UNIVERSITY OF PLYMOUTH
Design Development
Report
MECH232
Group M
5/20/2016
Anthony McNamara
Kate Martinimo
Tarig M A Halim
Annabella Conmee
Temi Danso
Abdul Eleson
Parit Halai
[Type the abstract of the document here. The abstract is typically a short summary of the contents of the
document. Type the abstract of the document here. The abstract is typically a short summary of the
contents of the document.]

2. Contents
1. Introduction .......................................................................................................................2
2. Initial Ideas and Discussion............................................................................................2
3. Development of Final Idea..............................................................................................2
1.1 Speed Calculations ..................................................................................................2
1.2 Shape of Hull.............................................................................................................4
1.3 Nose Cone/Hatch .....................................................................................................4
1.4 Feasibility Calculations ...................................... Error! Bookmark not defined.
2 Components......................................................................................................................5
2.1 Propeller.....................................................................................................................5
2.2 Fins .............................................................................................................................6
2.3 Steering......................................................................................................................7
4. Manufacturing Methods................................................................................................ 14
5. Final Design................................................................ Error! Bookmark not defined.
6. Conclusion...................................................................................................................... 16
7. References..................................................................................................................... 17

3. 1 Introduction
This report gives insight into the design development process from concept to final design of Mazu,
the two person human powered submarine. The design challenge is to package two riders into as
small and streamlined submarine shell as possible while ensuring the submarine is safe and
controllable.
Project meetings occurred once a week to constantly ensure all group members were on task. The
progress of these can be seen in the Gantt Chart and Meeting Minutes that were made each week.
The idea was constantly developed through an iterative process. Throughout this process, weekly
meetings were done to enhance communication with the clients. Critical components analysis was
done with the use of CES Edupack.
Section 2 includes initial design sketches and CAD models. Information on the selection of
materials and manufacturing methods is found in Section 5. By careful evaluation and research,
alterations were made to create a fully functional final design. All calculations that were made are
shown in their respective sections.
2 Initial Ideas and Discussion
A specification was created and a brainstorm was made to generate innovative ideas. Initial
research was done on the steering, prop design, geometrics and propulsion methods. Following
that, 8 initial designs were drawn and labelled with various rider positions and component ideas. A
feasibility matrix and FMECA was made with 5 failure modes for each design.
An evaluation matrix was used on the 8 designs mentioned above. The following 3 concepts were
chosen and combined to create the final design. Another feasibility matrix was made comparing
the time taken, cost, stability, ease of manufacture and safety for the 3 chosen concepts. Table
2-1 shows the key differences between the 3 concepts.
Table 2-1: Features of Concept Designs Concept
Shape of
Hull
Rider
Position
Sitting
Position
Driver
System
Driver
System
Position
Fins Fin
Position
A Long,
narrow
Inline Upright Variable
pitch
propeller
Rear of
submarine
4 Rear
B Wide Side by
Side
Laying
forward
Single
propeller
Rear of
submarine
2 Centre
C Long,
narrow,
compact
Inline Front
facing
Contra
rotating
Rear of
submarine
2 Centre
3 Developmentof Final Idea
3.1 Speed Calculations
Table 3-1 below shows the calculations that were carried out for the speed predictions of concepts
A, B, C and the final design.

4. Table 3-1: Speed predictions for concept and final designs
Concept Length
(m)
Width
(m)
Height
(m)
Total Final
Resistance at
Gate 4
(N)
Time from
Gate 1 to
Gate 4
(s)
Average
Speed (Gate
1 to Gate 4)
(m/s)
A 6.09 0.87 0.87 75.15 37.732 1.916
B 2.40 1.18 0.93 78.377 37.559 2.081
C 3.85 1.00 1.00 75.137 37.026 1.918
Final
Design
3.18 0.68 0.95 92.827 27.780 3.6
The length, width and height were obtained from the CAD models. Equation 1 was used to
calculate the total resistance at Gate 4 and the values that were used to perform this calculation
are shown in Error! Reference source not found..
𝑅 𝑇𝑂𝑇𝐴𝐿 =
1
2
× 𝜌 × 𝑣2
× 𝑐𝑑𝐴 𝑇𝑂𝑇𝐴𝐿
Equation 1
Table 3-2: Values used in Equation 1
Symbol Meaning Units Formulae Value Source
𝝆 Water
Density
kg/m3 1000 Water
tables
𝒗 𝟐
Final
velocity
m/s
𝒄𝒅𝑨 𝑻𝑶𝑻𝑨𝑳 Torpedo
drag
coefficient x
area
m2 Type equation here. calculated
𝑹 𝑻𝑶𝑻𝑨𝑳 𝑅 𝑇𝑂𝑇𝐴𝐿 =
1
2
× 𝜌 ×
𝑣2
× 𝑐𝑑𝐴 𝑇𝑂𝑇𝐴𝐿
calculated
The time from gate 1 to gate 4 was calculated using Equation 2 and the average speed was
calculated using Equation 4Equation 3.
𝑡𝑔(1 𝑡𝑜 4) = 𝑡𝑔4 − 𝑡𝑔1
Equation 2
𝑣 𝑎𝑣𝑔 =
𝑠4 − 𝑠1
𝑡𝑔 (1 𝑡𝑜 4)
Equation 3
where:
𝑠1 – distance at Gate 1
𝑠4 – distance at Gate 4

5. 3.2 Shape of Hull
3.3 Nose Cone/Hatch
Initially a combined nose cone hatch was
considered shown in Figure 1. The hatch would
be manufactured using a transparent material,
with a hinge placed at the bottom of the hatch in
order for it to be opened/closed. Although
Concept A
Originally concept A was chosen for the shape of
the hull and rider position, yet this design led to an
excess of wasted space due to the great length.
This excess space meant the submarine had a
larger surface area than necessary, therefore not
as optimised, resulting in lower speed predictions
shown in 𝑅𝑇𝑂𝑇𝐴𝐿=
1
2
× 𝜌 × 𝑣2
× 𝑐𝑑𝐴 𝑇𝑂𝑇𝐴𝐿
Equation 1
Table 3-2: Values used in Equation 1
Symbol Meaning Units Formulae Valu
𝝆 Water
Density
kg/m3 1000
𝒗 𝟐
Final
velocity
m/s
𝒄𝒅𝑨 𝑻𝑶𝑻𝑨𝑳 Torpedo
drag
coefficient
x area
m2 Type equation here.
𝑹 𝑻𝑶𝑻𝑨𝑳 𝑅 𝑇𝑂𝑇𝐴𝐿 =
1
2
× 𝜌 ×
𝑣2
× 𝑐𝑑𝐴 𝑇𝑂𝑇𝐴𝐿
The time from gate 1 to gate 4 was
calculated using Equation 2 and the
average speed was calculated using
Equation 4Equation 3.
𝑡𝑔(1 𝑡𝑜 4) = 𝑡𝑔4 − 𝑡𝑔1
Equation 2
𝑣 𝑎𝑣𝑔 =
𝑠4 − 𝑠1
𝑡𝑔(1 𝑡𝑜 4)
Equation 3
where:
𝑠1 – distance at Gate 1
𝑠4 – distance at Gate 4
.
Concept B
In order to minimise this wasted space,
reduce resistive forces and make the
submarine rider positions as compact as
possible Design D was carried forward, thus
resulting in faster speeds.
Concept C
The large width (shown in table 1) needed
to cater for two riders side by side led to an
increase in drag. Although the final speed
was less than that of concept A the resistive
forces meant that speeds were not optimal.
Final Design
The final design utilises all space, therefore
decreasing drag forces and resulting in the
fastest speeds.
Figure 1: Original combined nose cone/hatch (Idea A)

6. this design provided ease of access, especially ease of access when manufacturing and
maintaining components within the submarine, ISR guidelines (ref 1) state that ‘crew’s face and
head areas shall be visible to the support and safety divers at all times’.
The agreed upon separate nose cone and hatch
enables divers to easily see the riders from above at
all times. Additionally rigidity of the hull will be
increased with a separate nose cone/hatch
arrangement. The visibility of the riders has not been
impaired as the new rider position encompasses a
step up position. The emergency hatch will be placed on the top of the submarine, with equal ease
of access to both riders, yet only one rider will be able to exit at a time.
4 Components
4.1 Propeller
The two propeller types that were considered are the variable pitch propeller and the contra-
rotating propeller. Concept B utilised a variable pitch propeller while Concept C used a contra-
rotating propeller. The advantages and disadvantages of each are listed in Table 4-1 below.
Table 4-1: Advantages and disadvantages of two different types of propellers
Variable Pitch Propeller Contra-Rotating Propeller
Advantages Disadvantages Advantages Disadvantages
Forward and
astern
operation
High initial cost 15-20% more
efficient
Noisy
Sources (Piksrys, et al.,
2015)
(CPP - Controllable
Pitch Propellers
Explained,2009)
(Contra Rotating
Propeller Drive
System User
Guide, 2012)
(Purpose ofcontra-
rotating props,2015)
Can change
speed of ship
without a
change of
main engine
Requires
regular
inspection
Torque
cancels out
Heavy
Sources (Piksrys,et al.,
2015)
(CPP - Controllable
Pitch Propellers
Explained,2009)
(Contra Rotating
Propeller Drive
System User
Guide, 2012)
(Purpose ofcontra-
rotating props,2015)
A contra-rotating propeller was chosen as the desired propeller to use. The ISR race is a straight
line race with the purpose of producing maximum speed for the duration of the race. Torpedoes
such as Bliss-Leavitt torpedo commonly use contra-rotating propellers to give the maximum speed
possible within a limited diameter as well as the ability to counteract torque. The torpedo has a
maximum speed of 26 knots over an 800 yard range (Detailed description of torpedoes, 1956).
Although, the contra-rotating propeller is noisy, this does not apply to Mazu as it is a human
powered submarine. Another disadvantage is the weight because performance is sacrificed in
order to carry it. However, an advantage is that the torque cancels out. This is because there are
now two contra-rotating propellers cancelling out the opposite’s torque.

7. 4.2 Fins
Initially using only 3 fins was considered to limit manufacturing costs, two on the side and one on
the top. This proved unfeasible as the submarine would roll and lose stability; hence using 4 fins
was agreed upon with two planes of control:
Two rudder planes will act together controlling the yaw and two dive planes will be able to act
together and in opposition, controlling both the roll and pitch. The contra-rotating propeller will also
minimise the unwanted roll.
 Max Chord: 0.15m
 Mean Span: 0.3m
 Pivot Axis Position: 0.03m
 +/-30° Rotation on all planes
Using the NACA 0012 foil profile:
 Max thickness at 12.2%: 0.0366m
 Distance from front of fin (x): At 22.5% of chord length: 0.0338
(NACA 0012 AIRFOILS (n0012-il), 2016)
MeanSpan
Max Chord
Pivot Axis
Position
Side View
Figure 3: Side view of the fin
Max
Thickness
Distance from x
Top View
Figure 2: Top view of the fin

8. 4.3 Steering
The steering mechanism for the chosen design was a system initially designed for aircraft when
hydraulic systems were not implemented. Since both aircraft and submarines require similar
control method it can be used for either machine. The three control mechanisms required are yaw
control, pitch control and roll control. The basis of the system is to use cables and pulleys to create
a system in tension where adjusting the yoke results in one side
creating slack in the line while the opposite creating tension and so
changing the direction around a fixed axis. All control mechanisms for
this design can be implemented on a single yoke. The controls
required are shown in Figure 4.
Figure 4: Control mechanism for an aircraft (A.I.B. Hasri, 2012)
For the submarine vehicle, there are four fins, the control mechanism
shown above needs to be adjusted accordingly. The elevator control turns along the dotted axis to
allow the elevator to turn up or down and this controls the pitch. The rudder control turns along the
dotted axis to give the left and right controls and this controls the yaw. The aileron control turns
along the axis to allow the ailerons to act in opposing directions, meaning that when the right
aileron acts downwards the left would move
upwards and this is to control the roll. So to
implement this in to a single system, the
diagrams below in Figure 5, , Error!
Reference source not found. show the
controls for a single rider.
Figure 5: Layout for pitch and roll control SIDEVIEW
The layout shown on the left and above demonstrates the basic layout
within the hull of the vessel. The cables can be pulled further to the side and
conform to the shape of the hull. This opens up more space for the riders.
The yoke has two movement ranges in the image to the left these are
longitudinal (forward/backward) and lateral (left/right). For the longitudinal
movement as both cables are pulled forward or backward, the cable
attaches to the appropriate pulley and is guided so it does not slip off the
transitional pulley. As seen in the diagram below, the layout has a lower
pulley and upper pulley and these are the control mechanisms for the roll
control. This system allows the top to pull to the left while the bottom pulls
right and vice versa.
The overall design also needs to take both riders
requiring controls as a problem which needs a
solution and one way to do that is shown in the
design below.
One of the major components in the system is the cable, and the
selection of this component was critical due to the requirements for the
performance of the cable. The system will put tension on the cable as it
requires the system to pull the hinges on the fins. The overall material
comparison list is limited by factors such as cost, mass, tensile strength
and elastic modulus.
Figure 6: Layout for
pitch and roll control
TOPVIEW
Figure 7: Layout of the
yaw

9. The cable must have an acceptable plastic limit so that the safety of
the riders is maintained. The overall chosen material for the steering
cables is NYLON Braided Cord rope 5mm in Figure 8, which has a
very good tensile strength to weight ratio. The pulley types are 52 mm
round groove- nylon pulley wheel rollers with 5mm rope allowance.
The total amount required based on the layout is 12 pulleys.
Figure 8: Nylon pulleys (ddopacc, 2016)
4.4 Bearings
In addition to the gears, the bearing is another essential component used to aid the functionality of
the submarine and its system of propulsion. It is a piece of machinery used to supplement and
assist the rotating shaft by reducing friction between each of the moving parts. So the basic
concept of the component is simple: things roll better when they are able to slide.
Ordinarily, bearings undergo two types of loading as shown in Figure 9Error! Reference source
not found., which are radial loading and axial loading. In the case of the submarine and the type
of gears that have been selected to be used (bevel gears) the loading
will be a combination of both as the bearings will not only be used for
the shaft but also the pedals and the drivetrain.
When first looking at bearings, it must be established which type is
most ideal and conventionally there are 2 primary types of bearings
which are ball bearings and roller bearings. Each of these can be
split into sub-groups with different specialities.
The bearings used are for a variety of functions. One application is
for the transition of pedal movement. This can use a basic ball
bearing system.
Figure 10: Sketchof Drivetrain
The other load points are the point between the hollow shaft and the solid shaft at the inner
propeller as shown in Figure 10. This requires the most attention and is used to support the radial
and axial load between the two components this requires a rolling type component so that the two
shafts can turn independently to each other as this is the whole purpose of the contra-rotating
propeller shaft design.
For the transition of pedal movement mentioned above, a pre-fabricated
bottom bracket can be used Figure 11. The Shimano UN55 Bottom Bracket is
the most viable choice for the system.
For the Bearings we require a bearing between the holder bracket and the
outer shaft. The second bearing is between the inner shaft and the outer
shaft. To calculate the appropriate bearings, a set of mathematical
formulae are used in conjunction with loads and manufacturer data
Figure 9: Above we can see
the direction of the axial load
on the shaft (parallel) as well
as the radial load
(perpendicular). The bearing
seen in the middle is the
medium between the rotating
inner shaft and the counter-
rotating outer shaft
Figure 11: Shimano
UN55 bottom bracket
with crank bearings
Invalid source specified.

10. regarding different bearing types.
Initially the shaft radial and axial loads are needed to calculate the dynamic load on the system.
The radial load is calculated using Equation 4 whereas the radial load is the predetermined force
(thrust) found in the load calculations spreadsheet. The Lf mentioned in the equation relates to the
load connecting factor. For this particular setup the load connecting factor Lf is 1.25.
𝐹𝑟 =
𝑇×𝐿𝑓
𝑅
𝐹𝑟 =
12.43309649×1.25
0.02
Equation 4: Radial load calculation
𝑃 = ( 𝑋 × 𝐹𝑟) + ( 𝑌 × 𝐹𝑎) 𝑃 = (0.56 × 777.0685306)+ (1.67 ∗ 221.5458489)
Equation 5: Dynamic load calculation
The value for P= 805.139948313N.
It is assumed the submarine will be tested multiple times before the competition and that the total
number of revolutions will amount to exactly 1000000 revolutions. Also assuming that the reliability
of the bearing is 90% then the safety factor would in turn be 1 Invalid source specified.. The life
exponent value for a roller type bearing would be 10/3 and so by rearranging the basic life rating
Equation 6 we can find the load rating value Cr.
𝐶𝑟 = ( √𝐿10
𝑝
)× 𝑃 𝐶𝑟 = ( √1
10
3
) × 805.139948313
Equation 6: Basic life rating equation
Symbol Meaning Units Value Source
d bore diameter m 0.02 Calculations spreadsheet
D Total shaft diameter m 0.05 Calculations spreadsheet
W width space between
shafts
m 0.01 Invalid source specified.
Fr Radial load N 777.0685306 calculated
Fa Axial load N 221.5458489 Calculations spreadsheet
T Torque Nm 12.43309649 Calculations spreadsheet
Lf load connecting factor - 1.25 Invalid source specified.
R Radius m 0.02 Calculations spreadsheet
P Equivalent dynamic load N 805.1399448 calculated
X Radial factor - 0.56 Invalid source specified.
Y Axial factor - 1.67 Invalid source specified.
S.F Safety factor (90%) - 1 Invalid source specified.
RPM revolutions per minute r/min 440 Calculations spreadsheet
r revolutions - 1000000 assumed
L10 Basic life rating 106
revolutions
1 calculated
Cr Basic dynamic load rating N 805.1399448 calculated
p Life exponent - 3.333333333 Invalid source specified.

11. Value of Cr = 805.139948313N.
When looking through a data base of bearings for the most appropriate
selection is the SKF NX 20 bearing shown in Figure 13 which is a roller type
needle bearing that has a ball bearing component added to support the
axial load Invalid source specified.. The bearing conforms to the Criticla
load factor and the width limitations of the prop shaft.
The various values calculated are assumed to be
exactly the same for both shafts as they are equal
and opposite in the contra-rotating design of the shaft.
This also means that for a housing bearing, which is used to support the
shaft the same values hold true. As a result for the housing bearing a
SY20TR SKF 20mm bore can be used.
4.5 Gears
The gearing system required for the drivers is based on a tandem Bicycle and follows the da Vinci
tandem design as in Error! Reference source not found. to allow individual rotation.
For the basic system a premade gearing system
works more efficiently in the scope of the project
timeline. For this reason, a variety of gearing
systems are compared and the shimano FC-
M171 Triple chainset is an option considered.
The diagram in Figure 14 shows the chainset
implements a 170mm crank arm and is made
from a combination of aluminium and stainless
steel components to provide a lightweight and
strong component.
This system is paired with the Shimano Acera FD-M360 front derailleur
system to complete a three- speed gearing system for riders to be able to
accelerate from zero to max velocity and then maintain the power output.
For the timing on the da Vinci design, a simple timing crank is also
required and a standard 24t crank can be attached to the secondary pedal
crack arrangement.
The rear freewheel is a component that attaches
the front chainset to the drivetrain. Since the
speed gearing is only selected for the front chainset, the rear freewheel
is a simple sprocket with 18 teeth that is connected to a chain tensioner.
The shimano onespeed freewheel in Error! Reference source not found. is
Front rider chain
Figure 13: NX20
series bearing
Figure 12: SY20TR
SKF
Figure 14: Shimano FC-
M171 triple chainset
Invalid source
specified.
Figure 15: Shimano
onespeed freewheel Invalid
source specified.

12. very good option for this component and is shown below.
4.5.1 Gear arrangement
Initially, the choice for which gear system was most suitable in terms of functionality for the
submarine was between Worm and Bevel gears.
Although both gears are able to change the direction of motion by 90° we agreed on using bevel
gears. The worm screw typically drives the worm gear and the worm screw is usually powered by
a shaft. Our design requires the reverse of this gear design, as the shaft will need to be powered
by the gear.
In comparison, the bevel gear is comprised of two gears set at perpendicular positions to each
other. The system works in rolling motion where the teeth push against each other. The bevel gear
will work well with the calculated 4:1 ratio, and easily change the direction needed to power the
shaft.
Figure 2: Initial Sketchof Gear Drive
4.5.2 Gear Material
When selecting the material for the gears, yield and tensile strength, price and durability in fresh
water were all considered.
Material Price £/kg Corrosion in fresh water σUTS σYield
Medium Carbon Steel 0.326-0.364 Acceptable 410-1200 305-900
Low Alloy Steel 0.351-0.389 Acceptable 550-1760 400-1500
Stainless Steel 3.69-4.07 Excellent 480-2240 170-1000
Aluminium Alloy 1.37-1.51 Excellent 65-386 50-130
Table 4: Material selection factors (ref CESEdupack)
Inner shaft
turning outer
propeller
Bevel gear pow ered by chain
drive frompedals, turning
pinions in opposite directions.
Outer shaft turning inner propeller
Pinion 2 connected to
bevelgear and outer shaft
Pinion 1 connected to
bevelgear and inner shaft

13. We decided upon using low alloy steel, due to its high tensile and yield strength, cheap price and
as the submarine is not in constant use, we agreed that its acceptable durability in fresh water
was satisfactory for our design.
3. Gear Sizing
A gear ratio of 4:1 for the propeller shaft was calculated using the submarine speed prediction
spreadsheet in order to give the highest average speed when the riders input is 50rpm at a
maximum 700W. Gears will be α = 20o made from low alloy steel
with σUTS = 550 Mpa and σYield = 400 Mpa.
Assumptions:
 18 teeth on the pinion therefore 72 teeth on the gear.
 Lewis Form Factor= 0.27
 Factor of safety =4 gives σmax = 400/4 = 100 MPa
 Module= 2mm
𝐷 𝑝𝑖𝑛𝑖𝑜𝑛 = 𝑚 × 𝑁 𝑝𝑖𝑛𝑖𝑜𝑛
= 0.002𝑚 × 20
= 0.04𝑚
𝐾𝑣 = 6/(6+ 𝑉)
=
6
6 + 0.419𝑚/𝑠
= 0.935
𝑉 =
𝜋 × 𝐷 × 𝑛
60
=
𝜋 × 𝐷 × 𝑛
60
= (𝜋 × 0.04𝑚 × 200𝑟𝑝𝑚)/60
= 0.419𝑚/𝑠
𝑃 =
𝜋 × 𝐷 𝑝𝑖𝑛𝑖𝑜𝑛
𝑁 𝑝𝑖𝑛𝑖𝑜𝑛
=
𝜋 × 0.04
18
= 0.0062𝑚
𝐹 =
(
𝑊𝑡
𝐾𝑣 × 𝑚 × 𝑌 × 𝜎 𝑚𝑎𝑥
)
105
= (
1617
0.935 × 0.002𝑚 × 0.32 × 100
)/105
= 0.279𝑚
𝐹𝐴𝑙𝑙𝑜𝑤−𝑚𝑖𝑛 = 3 × 𝑃
= 3 × 0.0062𝑚
= 0.0188𝑚
𝐹𝐴𝑙𝑙𝑜𝑤−𝑚𝑎𝑥 = 5 × 𝑃
= 5 × 0.0062𝑚
= 0.0314𝑚
𝑊𝑡 = 𝑃/𝑉
=
700𝑊
0.419𝑚/𝑠
= 1671𝑁

14. Symbol Meaning Units Value Source
Npinion Pinion Teeth 20 Assumed
Ngear Gear Teeth 80 Gear ratio xNpinion
Y Lewis Form Factor 0.32 (BudynasandNisbett, 2011)
m Module m 0.002 Assumed
Dpinion Pitch diameter pinion m 0.04 Calculated
Dgear Pitch diameter gear m 0.16 Calculated
V Velocity (pitch line) m/s 0.419 Calculated
Wt Force N 1671 Calculated
Kv Velocity Factor 0.935 Calculated
F Face Width m 0.028 Calculated
Sd Shaft centres distance apart m 0.1 Calculated
P Pitch m 0.0062 Calculated
Fallow -min Allowable face width minimum m 0.0188 Calculated
Fallow -max Allowable face width maximum m 0.0314 Calculated
The gears will be outsourced, an example was found from HPC gears (HPC, no date) which
matches the module, and gear ratio. The necessary gears will cost £283.94 and will weigh 1.52kg.
4.6 Harness
To keep the riders in place and give them
an anchor point a simple harness is
devised which attaches with a clip to a
hook on the beam. This gives the rider an
opposing pull force to the pushing force on
the pedals. This is easily achieved with
a Panoply Standard Body Harness
shown in Figure 16. This will be
attached to a Harness Clip with a "D" Ring as seen in Figure 16. The
harness clip attaches to a hooking point on the frame.Figure 17: Harness clip
Figure 16: Panoply Harness

15. 5 Manufacturing Methods
5.1. Material of Hull
The material used for the hull of the submarine was decided based on the most important
mechanical properties that were required for the design. These included fibre to volume ratio, fibre
orientation and void % (percentage of air bubbles). Also, things such as the tolerances,
dimensions of the hull and its geometric complexity was also analysed. All in all, with these facets
of the design considered, it was concluded that fibreglass would be used as the base material of
the hull. It is a material that enables considerable flexibility in terms of the design as it can be
fabricated using simple tools; not requiring any welding or torches (Gerard, 2015).
 It is extremely lightweight (acFibreglass, 2004) and only 2/3 the weight of aluminium and 25%
the weight of steel (Gerard, 2015).
 It possesses high mechanical strength. It is incredibly strong and stiff for its weight and can
out-perform other materials such as steel & aluminium (acFibreglass, 2004).
 It has high impact strength so the submarine wouldn’t change shape if it was to rupture or
undergo any plastic deformation from any impact. (Smith, 1991).
 It has very good formability:
1. Easier to mould into the desired shape than most other materials (acFibreglass, 2004).
2. Good formability means it’s also cheaper to manufacture than other materials which helps
reduce the overall cost of the submarine design.
 It has low maintenance. (acFibreglass, 2004).
 It has good stiffness with a modulus of elasticity of 2.8 x 10^6 psi (Gerard, 2015).
5.1 Material for Nosecone & Hatch
For the nose cone and hatch of the submarine, it was decided that the material used would be
perspex glass which is a form of acrylic Error! Reference source not found..
 It is a material that possesses high strength & durability, good formability as well as being
cheap (Hargrove, 2015).
 Good formability means that it can be moulded into the concave shape for the sub more
efficiently (PLASKOLITE, 2016).
 It is lightweight and much easier to carry when compared to ordinary glass (PLASKOLITE,
2016).
 It has transparent properties that enable good and clear view through the front of the sub by
passengers (Hargrove, 2015).
Figure 18: An image displaying a boat hull
made from fibre glass (ec21,2009)

16. 5.2 Hinges
It was decided that a rubber (silicone) seal would be used for the hatch and nose cone of the
submarine. Evidently, this will act as a seal around the edges to eliminate any spaces where water
may seep in. The silicone elastomer used to create the sealant is useful for this as it has
properties such as being: non-reactive, stable and resistant to extreme conditions which is very
useful for a submerged vessel.
For the selection of the hinges used for the hatch, it was important to consider that the door that
comprised the hatch would need to be able to be pushed all the
way to the top so the hatch used needed to have this degree of
flexibility. It was also important that the hatch had a locking
mechanism so that when the door was opened it wouldn’t
come crashing back down again. The hatch that was selected
was able to encompass all of these desires and this was a
stainless steel, self-closing hinge. Stainless steel was used to
prevent the rusting of the component from
exposure to water.
To ensure the hatch is kept in place
during operation, a simple bar lock
can be used on the opposite side of
the hinges. The image below shows
this mechanism
Figure 20: (McNaughtuns, 2016) image of lock preventing the hatch from opening during operation.
5.3 Foam Material
It was essential that our submarine design possessed some sort of component that would help
maximise its buoyancy and stability in water.
This component would be foam with the material being syntactic foam which is a composite
material has glass microspheres within an epoxy resin matrix (Synfoam, 2016).
It has high strength, low density with very low moisture absorption with the latter two properties
being most required (Luong, 2011). The low density is what enables it to supplement the sub’s
buoyancy and increases efficiency whilst it’s low moisture absorption implies that it does not react
and is unaffected by water when the submarine is submerged.
Figure 19: Image of stainless steel locking hinge (Alibaba, 2014)

17. Figure 21: Image displaying the microspheres within the epoxy resin matrix of (ec21, 2009) the foam (PHYS ORG, 2015)
6 Final Design
Figure 22 shows an image of our final design with a representation of all the components, the rider
positions, fins, propellers and overall shape of the submarine.
Figure 22: Solidworks drawing of Final Submarine
7 Conclusion
In conclusion or final project met all the requirements and design specifications. The FEA analysis
was successful resulting in high probability of success of the vessel for the race. The final velocity
and time taken for the vessel was very fast resulting in a good race performance. The
manufacturing process and material that will be used for the design are environmentally friendly as
well cheap. The vessel is fairly easy to design due to the simplicity of components used. The
overall design was made so that the vessel is as small as possible resulting in a good
performance.

18. 8 References
(n.d.).
(n.d.). Retrieved from http://phys.org/news/2015-07-syntactic-foam-sandwich-hunger-
lightweight.html
A.I.B. Hasri, J. B. (2012, 10 1). Devices operated by hydraulic system in Aircraft. Retrieved from
Sslide share: http://www.slideshare.net/amaliqmal/devices-operated-by-hydraulic-system-
in-aircraft
acFibreglass. (2004). Advantages of fibre-reinforced plastics. Retrieved from acFibreglass:
http://live.isitesoftware.co.nz/acFibreglass/aboutus/
Alibaba. (2014). Alibaba. Retrieved from Alibaba.com: https://www.alibaba.com/product-
detail/supper-steel-hinges-adjustable-locking-hinge_531681410/showimage.html
Contra Rotating Propeller Drive System User Guide. (2012, January 28). Retrieved from
http://www.ralphschweizer.com/download/Contra%20User%20Installation%20Guide%20VII
I%201-28-2012.pdf
CPP - Controllable Pitch Propellers Explained. (2009, April 23). Retrieved from Bright Hub
Engineering: http://www.brighthubengineering.com/naval-architecture/32845-cpp-
controllable-pitch-propellers-explained/
ddopacc. (2016). 52mm Round Groove - nylon pulley wheels roller. Retrieved from ebay:
http://www.ebay.co.uk/itm/52mm-Round-Groove-nylon-pulley-wheels-roller-for-5-8-10mm-
rope-C52-5-8-
10B/151254299441?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26alg
o%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D7a8861dba2a048
bd93326508d745d
Detailed description of torpedoes. (1956). Retrieved from
http://www.history.navy.mil/museums/keyport/html/part2.htm
ec21. (2009, October 10th). Speed Boat/Fibreglass Boat. Retrieved May 02, 2016, from
Guangzhou Sunnyhoo Aquatic Equipment Co., Ltd:
http://charlottef.en.ec21.com/Speed_Boat_Fibreglass_Boat--3812598_4416743.html
Gerard, K. (2015, August 4). CRAFTECH BLOG. Retrieved 2016, from CRAFTECH INDUSTRIES:
http://info.craftechind.com/blog/the-benefits-of-fiber-reinforced-plastic-vs.-traditional-
materials
Hargrove, M. H. (2015). Exploring the Advantages and Disadvantages of Acrylic Aquariums.
Retrieved 2016, from Dummies: http://www.dummies.com/how-to/content/exploring-the-
advantages-and-disadvantages-of-acry.html
Luong, F. S. (2011). The Synthesis, Compressive Properties, and Applications of Metal Matrix
Syntactic Foams. Retrieved from TMS: http://www.tms.org/pubs/journals/jom/1102/rohatgi-
1102.html

19. McNaughtuns. (2016). Retrieved May 03, 2016, from McNaughtans:
http://www.mcnaughtans.com.au/products/locks
NACA 0012 AIRFOILS (n0012-il). (2016). Retrieved May 2016, from
http://airfoiltools.com/airfoil/details?airfoil=n0012-il
PHYS ORG. (2015, July 16). Syntactic foam sandwich. Retrieved 05 01, 2016, from Phys org:
http://phys.org/news/2015-07-syntactic-foam-sandwich-hunger-lightweight.html
Piksrys, P., Chakraborty, S., Verma, A., Glover, F., Biswas, T., C, A., et al. (2015, January 28).
Life at sea. Retrieved from Marine Insight: http://www.marineinsight.com/naval-
architecture/controllable-pitch-propeller-cpp-vs-fixed-pitch-propeller-fpp/
PLASKOLITE. (2016). Using incredible strength with aesthetic beauty. Retrieved 05 06, 2016,
from PLASKOLITE: http://www.plaskolite.com/AboutAcrylics/WhatIsIt
Purpose of contra-rotating props. (2015). Retrieved from
http://aviation.stackexchange.com/questions/14820/what-is-the-purpose-of-having-contra-
rotating-props-on-an-aircraft
Santa Monica Plastics. (2015). In God We Trust. Retrieved 04 21, 2016, from Santa Monica
Plastics: https://santamonicaplastics.com/shop/acrylic-sheets-more-cut-to-size/acrylic-
sheets-cut-to-size-clear/
Smith, C. (1991). Marine Structures. Retrieved from Science Direct:
http://www.sciencedirect.com/science/article/pii/0951833991900187
Synfoam. (2016). High strength syntactic foam for demanding applications. Retrieved from
SynFoam : http://synfoam.com/synfoam-hp-high-performance-syntactic-foam/