Presentation on maneuvering and collision avoidance with special focus on large tonnage vessels.
Maneuverability limits and last moment maneuver are thoroughly shown in this material.
Mooring and Unmooring operation during berthing and un-berthing of vessel is critical. The cadets are weak links in the team till they gain some experience. This presentation would help cadets to understand ,appreciate hazards and consequences. They can do spot risk assessment based on learning from presentation. Hope this presentation will help in reducing accidents arising from Mooring Ops.
Thanks for watching the slides ,await for your inputs.
Capt. Vivek Trivedi
smrviv@yahoo.co.in
Presentation on maneuvering and collision avoidance with special focus on large tonnage vessels.
Maneuverability limits and last moment maneuver are thoroughly shown in this material.
Mooring and Unmooring operation during berthing and un-berthing of vessel is critical. The cadets are weak links in the team till they gain some experience. This presentation would help cadets to understand ,appreciate hazards and consequences. They can do spot risk assessment based on learning from presentation. Hope this presentation will help in reducing accidents arising from Mooring Ops.
Thanks for watching the slides ,await for your inputs.
Capt. Vivek Trivedi
smrviv@yahoo.co.in
An Offshore supply vessel is a multi-task vessel and has to be designed for many different purposes. This is contrary to most other ships used worldwide. In general, the geographical location where the offshore activity takes place is an important indicator of the choice of supply vessel.
Factors like weather conditions, the amount of equipment needed and the distance from the shore
are important for what properties the vessel should have. The deep-water oilfield market is
becoming more important as the conventional oilfield market in shallow water cannot meet the
energy requirements from the consuming market. The Offshore Supply Vessels (hereafter it is
called OSVs) market is becoming booming and the demand for OSVs has never reached the extent
like today in previous periods.
In this project an offshore supply vessel will be designed according to ABS Rules.
The ship at sea or lying in still water is constantly being subjected to a wide variety of stresses and strains, which result from the action of forces from outside and within the ship.
DVAI fabrique des fonds bombés selon la norme NFE 81 100 : GRC, PRC, MRC et Elliptiques. Le document présente les dimensions des fonds bombés : diamètre, hauteur, rayon de bombage, rayon de carre, hauteur des bords droits et volume. www.dvai.fr
An Offshore supply vessel is a multi-task vessel and has to be designed for many different purposes. This is contrary to most other ships used worldwide. In general, the geographical location where the offshore activity takes place is an important indicator of the choice of supply vessel.
Factors like weather conditions, the amount of equipment needed and the distance from the shore are important for what properties the vessel should have. The deep-water oilfield market is becoming more important as the conventional oilfield market in shallow water cannot meet the energy requirements from the consuming market. The Offshore Supply Vessels (hereafter it is called OSVs) market is becoming booming and the demand for OSVs has never reached the extent like today in previous periods.
In this project, an offshore supply vessel will be designed according to ABS Rules.
Types of Gravity Dam
Forces Acting on a Gravity Dam
Causes of failure of Gravity Dam
Elementary Profile of Gravity Dam
Practical Profile of Gravity Dam
Limiting height of Gravity Dam
Drainage and Inspection Galleries
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
5. Equations of motion in horizontal plan
• Surge : X = m (ů̊G - vG Ψ ̊)
• Sway : Y = m (v̊G + uG Ψ ̊)
• Yaw : N = Iz Ψ ̊ ̊
# Move the original point to midship point :
X = m (ů - vΨ ̊ - XG Ψ ̊²)
Y = m (v̊ + uΨ ̊+ XG Ψ ̊ ̊ )
N = Iz Ψ ̊ ̊ + m XG (v̊ +u Ψ ̊ )
y
X
C.G
y
X
C.G ¤
C.G ( XG , 0 , ZG )
Assuming that the ship is symmetrical
about its longitudinal centerplane .
Ψ ̊ = r
Ψ ̊ ̊ = r ̊
uG = u
vG = v + XG Ψ ̊
6. Equations of motion
Now we have equations of motion, with the original of the coordinate system
lying on the midship point :
X = sum of all forces acting on the hull in ship-fixed abscissa axis or surge or axial forces .
Y = sum of all forces acting on the hull or sway forces .
N = sum of all moments acting on the hull in horizontal plane or yaw moments .
u = surge or axial component of instantaneous speed .
u ̊ = surge or axial acceleration .
v = sway velocity .
v ̊ = sway acceleration .
r = yaw rate or yaw angular velocity .
r ̊ = yaw acceleration .
m = vessel mass .
Iz = mass moment of inertia of a vessel relative to vertical axis Z .
XG = abscissa of the center of gravity
X = m (u ̊ - vr - XG r ²)
Y = m (v ̊ + u r + XG r ̊ )
N = Iz r ̊ + m XG (v ̊ +u r )
7. Hull Forces in Linear Formulation
X = Fx (u, v, u ̊, v ̊, r, r ̊)
Y = Fy (u, v, u ̊, v ̊, r, r ̊)
N = Fψ (u, v, u ̊, v ̊, r, r ̊)
• Fx, Fy = components of the hydrodynamic force .
• Fψ = hydrodynamic moment in the horizontal plane .
Final linear formulae for the hull forces are:
X =
𝝏𝑿
𝝏𝒖
( u - V) +
𝝏𝑿
𝝏𝒗
v
Y =
𝝏𝒀
𝝏𝒗
v +
𝝏𝒀
𝝏𝒗 ̊
v ̊+
𝝏𝒀
𝝏𝒓
r +
𝝏𝒀
𝝏𝒓 ̊
r ̊
N =
𝝏𝑵
𝝏𝒗
v +
𝝏𝑵
𝝏𝒗 ̊
v ̊+
𝝏𝑵
𝝏𝒓
r +
𝝏𝑵
𝝏𝒓 ̊
r ̊
Hydrodynamic Derivatives
8. Hydrodynamic Derivatives
X 𝒖 =
𝝏𝑿
𝝏𝒖
, X 𝒗 =
𝝏𝑿
𝝏𝒗
: surge hydrodynamic derivatives
Y 𝒗 =
𝝏𝒀
𝝏𝒗
, Y 𝒗 ̊ =
𝝏𝒀
𝝏𝒗 ̊
: sway hydrodynamic derivative by transversal component of velocity and accelerations
Yr =
𝝏𝒀
𝝏𝒓
, Y 𝒓 ̊ =
𝝏𝒀
𝝏𝒓 ̊
: sway hydrodynamic derivative by yaw rate and yaw acceleration
N 𝒗 =
𝝏𝑵
𝝏𝒗
, N 𝒗 ̊ =
𝝏𝑵
𝝏𝒗 ̊
: yaw hydrodynamic derivative by transversal component of velocity and accelerations
N 𝒓 =
𝝏𝑵
𝝏𝒓
, N 𝒓 ̊ =
𝝏𝑵
𝝏𝒓 ̊
: yaw hydrodynamic derivative by yaw rate and yaw acceleration
9. Rudder Forces
XRd = 0
YRd = Yδ δR
NRd = Nδ δR
δ
C.G
HeadingDrag
Thrust
Rudder Lift force
lever
The moment of lift
force deviates the
vessel from its
original course
Hydrodynamic Forces on the Hull
10. Ship Maneuverability
is the ability of a ship to keep or change its state of motion under the control
actions, i.e., to keep the straight-ahead course with constant speed.
• Ship maneuverability includes the following contents :
1. Inherent dynamic stability
2. Course keeping ability
3. Initial turning/course changing ability
4. Yaw checking ability
5. Turning ability
6. Stopping ability
11. Dynamic stability “straight line stability”
• A ship is dynamically stable on a straight course .
The resultant deviation from the original course will depend on :
1. Degree straight line stability of the ship
2. Magnitude and duration of the disturbance.
13. Course keeping ability “directional stability”
• Is the ability of the steered ship to maintain its original course direction.
Original course
Disturbance
Y
X
Final course
14. • Initial turning ”course changing ability” :
The ability of ship to change its heading as response to a control action. A ship
with good initial turning ability will quickly get into turning or change its
original course after the control action.
• Yaw checking ability :
the ability of the steered ship to respond to the counter rudder action applied
in a certain state of turning.
• Turning ability :
the ability of ship to turn under the hard over rudder action.
• Stopping ability:
the ability of ship to stop with engine stopped (inertia stop) or engine full
astern (crash stop) after a steady approach at full speed.
15. Coupled motions in turning
• Heel during turning occurs as a result of the intrinsic coupling of
sway, yaw, and roll caused by the center of gravity.
• In a surface vessel, the fluid forces act below the waterline, but
the center of gravity is near the waterline or above.
16. Heel angle in a steady turning
G
E
H
K
FR = Yδ δr
FH = Y 𝒗v+ Yr r
FG=
mv²
𝑹
FR
FH
FG
𝒇𝒚
FH - F R = mv²
𝑹
𝑀
Moment causing Heel = (FH - F R )* KG + F R * KH – FH * KE
= (FH - F R )* GE – FR EH
Mg GM 𝒔𝒊𝒏 ∅ = (FH - FR )GE
Mg GM 𝒔𝒊𝒏 ∅ =
mv²
𝑹
GE
GE
GM
= 𝑹 g
𝒔𝒊𝒏 ∅
v²
𝒔𝒊𝒏 ∅ =
v² GE
𝑹 𝒈 GM
Z axis
Y axis
FR
FG
Y𝒗
18. Required and Recommended Maneuvers
Sea trials are the final confirmation of a vessel’s maneuvering
qualities and its maneuverability prior to its delivery.
The required maneuvers are:
• Turning test : For initial turning and steady turning ability .
• 20/20 zig-zag test : For yaw checking ability and course-keeping ability .
• Stopping test (Crash Stop) : For emergency stopping ability .
The recommended maneuvers are:
• Pull-out test : For straight-line stability .
• One of the spiral tests : For straight-line stability if the pull-out test indicated that the
vessel is directionally unstable.
19. Conditions of Trials
Maneuverability of a vessel may be significantly influenced by hydrodynamic interaction with
the sea bottom, banks and other vessels passing nearby. In addition, winds, waves, currents
and tides .
In order to get credible results, sea trials are to be carried out in the following conditions:
• Deep and unrestricted waters :
1. Water depth at the trial site is to be more than four times of vessel draft at midship.
2. The site should be free from other traffic and far enough from banks that any maneuver
would not make any bank closer than two ship lengths.
• Winds and waves
• Tides and currents : It is recommended to avoid places with strong current and/or tidal
influence when choosing a trial site. If current cannot be avoided, it should be uniform and the
tests should be performed both for initial following and initial ahead current.
20. Dieudonne spiral maneuver
There are two kinds of spiral test :
1. Direct spiral test, also called Dieudonné’s spiral test
2. Reverse spiral test, also called Bech’s reverse spiral test
which are performed to evaluate :
1. Ship dynamic stability “straight line stability”.
2. Course keeping ability “directional stability”.
21. Steps
• The direct spiral test is an orderly series of turning circle tests
1. Accelerate ship up to full speed
2. changes the rudder angle ẟ in sequence of
+15° » +10 ° » +5 ° » 0 ° » » -15° » -10 ° » -5 ° » 0 °
3. Record the rate of turn “r” , when it become constant.
4. plot the Relation between Rudder Angle and Rate Turn
22. ẟ : Rudder Angle
r : Rate of Turn
PORT
STARBOARD
PORT
STARBOARD
5 10 15 20- 20 -15 -10 - 5
23. Bech Reversed Spiral (In-direct)
This is a manoeuvre aimed at giving a feel for a ship’s directional stability.
Steps:
1. Accelerate ship up to full speed
2. The spiral maneuver is to be steering a constant rate of turn of 35 deg/sec.
To starboard with a minimum of rudder movement.
3. When steady conditions have been reached the mean rudder angle
required to maintain this constant rate of turn, should be noted.
4. The rate of turn is then to be reduced to 35 deg. Starboard and the
corresponding rudder angle should be noted.
5. The same procedure is followed for a range of rates of turn.
24. Conclusion:
ẟ
Ψ ̊ r
ST.BoardPort
ST.Board
At zero rudder angle,
there is a value for rate of
turn Ψ ̊( different from
starboard and port ).
It is impossible to predict
the direction of ship
Range of
unstable angles
of rudder
25. • Stable: If the ship is stable there will be a unique rate of turn for each rudder
angle
• Unstable: If the ship is unstable the plot has two ‘arms’ for the smaller rudder
angles, depending upon whether the rudder angle is approached from above
or below the value.
• It is impossible to predict which way the ship will turn, let alone the turn rate,
as this will depend upon other disturbing factors present in the ocean.
• The manoeuvre does not give a direct measure of the degree of stability,
although the range of rudder angles over which response is indeterminate is a
rough guide.
26. The difference between Dieudonne spiral ( direct spiral ) and
Bech Reversed spiral (in-direct):
• For the dis-advantages of Dieudonne spiral, Bech proposed an
alternative approach, where instead of holding the rudder steady
until a constant rate of turn is achieved, the ship is actively steered
at a constant rate of turn using the rudder.
• In general, the results of Dieudonne method and Bech method are
similar but the latter gives in the unstable part of the rate of turn
versus rudder angle.
27. Pull-out Maneuver:
Developed as a simple test to give a quick indication of a ship’s course stability.
Steps:
1. Accelerate up to full-ahead speed.
2. The ship is held on a steady course and at a steady speed.
3. Commence maneuver with application of 20 deg. Port rudder.
4. When rate of turn is steady, return rudder to amidships.
5. Record rate of turn.
6. Repeat maneuver for 20 deg. Starboard rudder.
28. Conclusion:
Ψ ̊ r
Port
ST.Board
T
20 ̊ If the ship is stable, the rate of turns will decay to
zero for turns to both port and starboard.
Rudder returned to amidship
29. Rudder returned to amidship
Ψ ̊ r
Port
ST.Board
T
If the ship is unstable then the rate of turn
will reduce to some residual rate of turn
Range of un stable rate
of turns
If the ship has a steering bias, then port and starboard turns
will decay to the same small rate of turns on which ever hand
the bias exists.
20 ̊
30. Weave Maneuver:
• Consider as a complementary to the pull-out maneuver and was developed
to determine the minimum rudder angle necessary to produce a reversal
rate of turn and so application to ships with little or no course stability.
31. Steps:
1. Accelerate up to full-ahead speed with the ship’s head to wind.
2. Commence maneuver with the application of 10 deg. Port rudder.
3. When a steady rate of turn has been achieved put the rudder over to 10 deg.
Starboard
4. If the ship’s heading changes from port to starboard apply 6 deg. Port rudder
and reverse the rate of turn ( without return rudder to amidship).
5. The procedure of reducing the rudder angle is continued until the point is
reached where the rudder angle is not sufficient to change the ship’s heading
32. Notes:
• The rudder angle at which this failure to respond to the rudder will be
different for port and starboard application, they will correspond to the
rudder dead band-width .
33. Turning Circle
Used to determine :
The effectiveness of the rudder to produce steady-state turning characteristics
Advantages of the trial :
Being economic in terms of time ,but if strong wind are experienced it is
preferable to arrange all the approach runs in the same direction relative to
wind
34. Turning Circle
• When the rudder is put over initially, the force acting on the rudder
tends to push the ship bodily to port of its original line of advance.
• As the moment due to the rudder force turns the ship's head, the
lateral force on the hull builds up and the ship begins to turn.
35. Turning Circle
The essential information to be obtained from this
manoeuvre consists of :
• tactical diameter
• advance
• transfer
• loss of speed on steady turn
• time to change heading 90 degrees
• time to change heading 180 degrees
36. tactical diameter
For 180 degrees
change heading
Maximum transfer
Transfer of 9o degree
change of heading
Steady
turning
radius
Drift angle,
Must be zero so that the
ship can rotate
Advance of 90
degree change of
heading
3rd phase2nd Phase
1st Phase
Turning Circle
37. Advance.(after 90 degree of heading)
The distance travelled by the center of gravity in a direction parallel
to the original course after the instant the rudder is put over.
Transfer.
The distance travelled by the center of gravity perpendicular to the
original course.
It should be noted that the tactical diameter is not the maximum value of the transfer.
Tactical Diameter of steady turning circle.
The maneuver should be obtained until 180 degree change of heading has been completed
,so that the advance and tactical diameter can be determined .
Maximum transfer and maximum advance .
Which are measured at the points of max. translation of the ship’s center of gravity
Turning Circle
38. v●
β
δ
r●
r ̊ ( yaw acceleration )
Phase 3Phase 2Phase 1
T
Turning Circle
δr (angle of rudder is kept fixed)
R (becomes constant)
β (drift angle)
v ̊
(acceleration starts high then reduced till become zero)
39. Zigzag Manoeuver (Z-Manoeuver)
The zig-zag manoeuver, sometimes called a Kempf manoeuver,
after G.Kempf, is carried out to study more closely the initial response of a ship to rudder
movements
This trial was proposed as a means of :
1- investigating the qualities of a free-running model
2- qualitative measure of the effectiveness of the rudder to initiate and check changes of heading
40. A typical manoeuver would be as follows:
1-accelerate ship up to full speed ,with the ship’s head to wind
Zigzag Manoeuvre (Z-Manoeuver)
2- the rudder is put over to 20 degrees and held
until the ship's heading changes by 20 degrees.
3-The rudder angle is then changed to 20 degrees in
the opposite sense and so on.
41. The manoeuver is repeated for a range of approach
speeds and for different values of the rudder angle and
heading deviation.
Zigzag Manoeuvre (Z-Manoeuvre)
42. Important parameters of this manoeuver are:
(a) the time between successive rudder movements
Zigzag Manoeuvre (Z-Manoeuvre)
(b) the overshoot angle which is the amount by which the ship's
heading exceeds the 20 degree deviation before reducing.
44. Stopping Test
The stopping test is performed to evaluate the stopping ability.
A full astern stopping test is conducted to determine :
the track reach of ship from the time when an astern order is given
until the ship is stopped dead in the water.
• Track reach :the total distance travelled along the ship's path.
45. Stopping Test
During stopping tests a ship’s speed is reduced
from some initial steady value to zero by
applying full astern power.
46. Stopping Test
the head reach :
distance travelled in the direction of the
ship's initial course
the lateral deviation :
the distance toport or starboard measured normal to the
ship's initial course.
the track reach :
the total distance travelled along the ship's
path
47. Stopping Test
Ships usually are directionally uncontrollable during this manoeuvre
so that the trajectory (path) is, to a large extent, determined by :
-the ambient disturbances
- initial conditions
- rudder actions.
(Although existing procedures allow rudder activity to keep the ship
as close to the initial course as possible, it should be noticed that
IMO requires the rudder to be maintained at midship throughout the
trial.)