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Ship Disaster Investigation
Teacher’s ManualContents
• Teacher’s Instructions
• Check Sheet for
Investigation
• Assessment Sheet
• Agent’s Manual
• Ship Disaster Cases
• Answer Key
Marine Kit – 4
This activity was developed under a grant from the National Shipbuilding Research Program (NSRP)
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
SHIP DISASTER INVESTIGATION
Teacher’s Instructions
This activity deals with the ship disaster case studies. Hypothetical ship disaster case studies are
given to the students. Though the cases are hypothetical, causes behind the disasters are real.
Students will play the role of Ship Disaster Investigation Agency’s (SDIA) agents, analyze the
case, find out the causes behind the disaster and give their suggestions for improvement. In this
way they learn about the terminology used in the industry, some ship design and construction
fundamentals, and right practices followed in the shipbuilding and shipping industry.
Kit Contents
• Activity kit contains Ship Disaster Investigation Agency’s agent guide, check sheet, ship
disaster cases and model solutions to the cases.
• Students need to bring calculator
• The kit contains material for one group (4-5 students). For additional groups, please make
copies of all documents.
Set Up
• This activity requires two class periods. (Day – 1 and Day – 2)
• Make copies of check sheets (1 for each group) and disaster case (1 for each group) before
starting the activity
• Ship Disaster cases recommendations
Use cases 1 and 2 for Middle School
Use cases 3 and 4 for High School
• Answer key (model solutions) is included in the kit for the teacher.
Day – 1
• Please use the power point presentation for day -1 activity. (10 to 15 min)
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
• Form investigation teams with 4-5 students in each.
• Day-1 activity involves analyzing the case and finding out the reasons behind the ship disaster.
(40 – 45 min)
• Each Investigation team gets one check sheet and one ship disaster case.
• Students should start filling the information in the check sheet after reading the case carefully.
• Students will refer to the agent’s guide and identify the possible reasons for the disaster.
• Students can use calculators if necessary.
• Please collect all the agent guides and keep them in the kit at the end of the activity.
Day – 2
• All the investigation teams present their findings to the class.
• Compare the findings with the model answers given in the kit.
• Explain the real reasons behind the disaster to the class.
• Use the assessment sheets to assess performance of each group, the group with maximum
number of points wins.
• Check the kit contents for any missing document and place the contents back in the box.
General
• Both the activities can be completed in a block schedule.
Check sheet for Investigation
1. Type of ship – cargo / container / oil tanker / cruise / chemical tanker ship
2. Length of ship (in meters) =
3. Height of ship (in meters) =
4. Beam of ship (in meters) =
5. Designed draft (in meters) =
6. Number of transverse bulkheads (if applicable) =
7. Number of longitudinal bulkheads (if applicable) =
8. Cargo carrying capacity =
9. Actual cargo at the time of disaster =
10. Type of cargo =
11. Density of cargo (if applicable) =
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Group No:
Names
1)
2)
3)
4)
Poor Fair Good Very Good Excellent
Quality Characteristics 1 2 3 4 5
Understanding the nature of the disaster
Ability of students to find the clues
Ability of students to find the reasons for the disaster
Group activity involvement
Presenting the findings of the analysis
Date(mm/dd/yy):
Ship Disaster Investigation Assessment Sheet
This assessment sheet is to be used by the teacher to evaluate
MarineTech Project Ship Disaster Investigation Lean Institute,ODU May 2011
Total Points
the Ship Disaster Investigation Activity
Includes Basic ship Terminologies and Investigation Check list
Sail Smooth, Sail Safe
Marine Kit – 4 Marine Kit – 4
MarineTech Project, Lean Institute ODU, May 2011
1. Ship Terminology………………………………………………………03
2. Motions of a Floating Body…………………………………………...09
3. Ship Stability…………………………………………………………….10
4. Free Surface Effect……………………………………………………..13
5. Effect of Water Density on the Draft…………………………………15
6. Displacement of Ship…………………………………………………..16
7. Loading of Ship………………………………………………………....17
8. Tanker Ships.…………………………………………………………....19
9. Speed of Ship..…………………………………………………………..20
10.Ship Power Plant………………………………………………………..21
11.SONAR……………………………………………………………………23
12.Unit Conversions……………………………………………………….26
Index
2MarineTech Project, Lean Institute ODU, May 2011
1. Ship Terminology
Starboard
Port
Stern
Bow
Bow : Front part of the ship
Stern : Rear part of the ship
Starboard : Right side of the ship
Port : Left side of the ship3
MarineTech Project, Lean Institute ODU, May 2011
Hull
•Most of the modern vessels have
double hull to prevent flooding in
case of accidents.
•Tankers have double hull to
prevent oil spilling in case of hull
damage.
•Double hull also serves as
ballast tanks in the partial loaded
or unloaded condition to keep
the center of gravity as low as
possible for stability.
Ship Hull
Hull is a body of a ship
Double Hull4
MarineTech Project, Lean Institute ODU, May 2011
Keel
http://web.nps.navy.mil/~me/tsse/NavArchWeb/1/module2/introductio
n.htm#
Keel of the ship is the
principal structural
member of a ship running
lengthwise along the
center line from bow to
stern, to which the frames
are attached.
Various terms used to define hull cross section
“fore” is the front part
“aft” is the rear part
5MarineTech Project, Lean Institute ODU, May 2011
Cross section of ship
Draft of a ship is the vertical distance between the waterline and the bottom
of the hull
Draft
FreeboardWaterline
Freeboard of a ship is the vertical distance above the waterline
Beam of a ship is the width of a ship at any cross section
Beam
6MarineTech Project, Lean Institute ODU, May 2011
Deadrise: Deadrise is an angle measured upward from a horizontal plane at
the keel level.
Flat bottomed vessels
have 0 (zero) deadrise.
Deadrise for “V” shaped
hull varies from bow to
stern.
Deadrise is very important feature in the stability of the vessel. A flat
bottomed boat rises on a plane quickly and provides a stable comfortable
ride in calm water – but will pound heavily in rough water. A vessel with
deadrise provides greater stability and comfort in rough conditions.
• Ocean going big ships are never flat bottomed in the fore and aft
hull sections, may be almost flat bottomed in the mid ship section.
• Ocean going vessel with full flat bottomed hull may capsize easily in
the heavy seas
Deadrise
7MarineTech Project, Lean Institute ODU, May 2011
Bulkhead: Bulkhead is a upright wall like structure within the hull of a ship.
• Bulkheads increase structural rigidity of the vessel
• Bulkheads create watertight compartments to prevent flooding in case of
hull breach or leak.
Longitudinal Bulkheads are used to create watertight compartments in
case of ship capsize. It also divides cargo into different sections and thus
helps improve stability of ship by creating different center of gravities for
different sections. (More on this in free surface effect)
Bulkheads
Bulkheads
8MarineTech Project, Lean Institute ODU, May 2011
2. Motions of a floating body
Any floating body has three motions namely Roll, Pitch and Yaw
Roll: Rolling is the motion of a floating body about the longitudinal axis ( axis
along the length of the body)
Pitch: Pitching is the motion about the transverse axis of the body (i.e axis
along the width of the ship.
Yaw: Yawing is the motion of a floating body about the vertical axis.
Control of all the three motions is very important for ship stability and
ride comfort. 9MarineTech Project, Lean Institute ODU, May 2011
3. Ship Stability
Center of Gravity (G), Center of Buoyancy (B), and Metacenter (M)
play very important role in stability of the ship.
The center of buoyancy, is the center of gravity of the volume of water
which the hull displaces. This point is referred to as B in naval
architecture. The center of gravity of the ship itself is known as G in naval
architecture. When a ship is upright, the center of buoyancy is directly
below the center of gravity of the ship.
10MarineTech Project, Lean Institute ODU, May 2011
Center of Gravity is the point where all the weight of the object can be
considered to be concentrated
Center of Buoyancy is the center of mass of the immersed part of ship or
floating object
Metacenter is the point where lines of action of upward buoyancy force intersect
When the ship is vertical, it lies above the center of gravity and so moves in the
opposite direction of the heel as ship rolls
Relationship between G and M
G under M: ship is stable
G = M: ship neutral
G over M: ship unstable
G
M
B
M
G
B
Stable Unstable11MarineTech Project, Lean Institute ODU, May 2011
When the cargo in the ship are evenly distributed, the ship will be
upright. The sum of the gravity forces of cargo and the ship will be
acting at one point - the Center of Gravity, G, acting downwards.
Similarly, the Center of Buoyancy of the ship will be acting at one point
B, acting upwards.
A ship is said to be in Stable Equilibrium if on being slightly inclined,
tends to return back to the original position.
However, a ship will be in Unstable Equilibrium when she tends to move
further from that original position on being tilted slightly. A ship in
Neutral Equilibrium will tend to neither return nor move further from that
position.
What is stable equilibrium?
12MarineTech Project, Lean Institute ODU, May 2011
Wave
• Force of wave heels the
ship to the starboard.
• Center of gravity of oil
shifts.
• Oil acts as a single
mass, hence the
change in the center of
gravity is drastic
• Force of wave and
change in the center of
gravity heels the ship
more and more without
giving it a chance to
come to its upright
position.
• As the ultimate effect of
wave force and big
change in center of
gravity ship capsizes.
4. What is the free surface effect?
This effect proves fatal in partially filled ocean going vessels in the
heavy seas.
13MarineTech Project, Lean Institute ODU, May 2011
Ship is fitted with
compartments, i.e.
(longitudinal bulkheads)
Now the liquid in the
tank acts as different
masses and center of
gravity of individual
mass changes.
But effect of changing
all the center of gravities
does not shift the center
of gravity of the ship as
significantly as before.
How to minimize the free surface effect?
The other way to minimize the free surface effect is to fill the tanks nearly full.
This does not give the liquid room and hence minimizes the free surface effect.
Tanker ships never sail partially filled 14MarineTech Project, Lean Institute ODU, May 2011
5. Effect of change in density of water on
the draft of a ship
Density of Fresh Water = 1000 kg / m3
Average Density of Sea Water = 1030 kg / m3
Draft of ship changes with the change in density of water
NewDensity
OldDensity
OldDraft
Draft New
Keeping the load same, change in the draft can be calculated
by following equation
Fresh water draft is more than salt water draft
Ships transiting between sea water and fresh water have to consider this
change in draft to avoid a danger of running aground15
MarineTech Project, Lean Institute ODU, May 2011
The word "displacement" arises from the basic physical law, discovered by
Archimedes, that the weight of a floating object equates exactly to that of the
water displaced
6. Displacement of ship
Displacement = actual total weight of the vessel
Unit of Displacement = long ton or metric ton
How to calculate Displacement of ship?
1. Volume of submerged part (cu. Feet) = length * Beam * Draft
2. Multiply this by block coefficient of hull
3. Multiply this figure by 64 to get weight of ship in pounds or divide by
35 to calculate weight in long tons
4. Using SI or metric system: displacement (in tons) is volume (in cubic
meters) multiplied by the specific gravity of sea water (nominally
1.025)
16MarineTech Project, Lean Institute ODU, May 2011
Lightship weight is the
displacement of the ship
only with no fuel,
passengers, cargo, water,
etc. on board.
Deadweight Tonnage
(DWT) is full load
displacement minus the
lightship weight. It includes
the crew, passengers,
cargo, fuel, water and
stores etc.
A ship can carry cargo weighing roughly 90% of its deadweight
tonnage
Full Load Displacement:
Displacement when ship is
loaded with cargo or
people to the point that it is
submerged to its load line
Plimsoll line or International Load Line
the mark on the hull of a ship that shows where the waterline is when the ship
is loaded to full capacity according to the condition of the water at the point
of loading.
17MarineTech Project, Lean Institute ODU, May 2011
7. Loading of Ship
• Cargo should be always evenly distributed
• Uneven distribution makes ship unstable
• Uneven distribution also creates stresses on the ship structure
• Cargo should be properly secured (e.g.in case of cargo like cars)
cargoofMass
cargoofVolumeStowage Factor =
Proper care should be taken to distribute the load evenly
when carrying high density cargo with stowage factor above
0.56
18MarineTech Project, Lean Institute ODU, May 2011
8. Tanker Ships
Slop tanks are provided for storage of dirty ballast residue and tank
washings from the cargo tanks
General Arrangement of Cargo and Ballast Tanks for Tankers
•Tankers are used to carry liquid and gaseous cargo
•All the tanker ships have double hull in order to prevent oil
leakage
•Partially filled tankers are highly unstable in heavy seas
because of the free surface effect
19MarineTech Project, Lean Institute ODU, May 2011
9. Speed of ship
Speed of a ship is measured in knots
• Modern ships are powered by diesel engines
• Some ships are powered by steam turbines also
• Nuclear power is used in defense naval ships
Propellers
Propeller
shaft
Power
Source
(Diesel
Engine /
Steam
Turbine/
Nuclear
power)
Loss of propulsion system can prove fatal, especially in heavy
seas as ship loses control over direction20
MarineTech Project, Lean Institute ODU, May 2011
10. Ship Power Plant
Most new ships today are powered by diesel engines,
though a few older ships are still powered by steam
turbines and reciprocating steam engines
Propeller
Propeller shaft
Power Plant
(Engine/ turbine)
21MarineTech Project, Lean Institute ODU, May 2011
• Power plant and propulsion system are the most critical
systems in any ship
• It gives the ship the force required to move
• Failure of power plant or propulsion system could be fatal as
ship loses control on the direction
• Loss of power or propulsion in heavy seas or near the shore is
very dangerous since ship may stray with the direction of
winds and waves and may run aground
22MarineTech Project, Lean Institute ODU, May 2011
11. SONAR
SONAR (Sound Navigation and Ranging)
SONAR is a technique that uses sound propagation under water
(primarily) to navigate, communicate or detect other vessels
Principle of SONAR: Reflection of sound waves
23MarineTech Project, Lean Institute ODU, May 2011
24
• A transmitter is used to transmit the signal
• A receiver is used to catch the reflection (echo)
• The time from transmission of a pulse to reception is measured
• Speed of sound in water is known
• Using the formula Speed = we can calculate the distance of
the object from the source of the pulse (transmitter)Time
ceDistan
SEA BED
Distance “d”
Time “t”
MarineTech Project, Lean Institute ODU, May 2011
Speed of sound in water is calculated using following equation
4388 + (11.25 × temperature (in °F))
+ (0.0182 × depth (in feet)
+ salinity (in parts-per-thousand)).
Speed of Sound
(feet /s)=
1 foot = 0.3048 meters
Distance from the object is calculated using formula
Distance =Speed of sound x time between transmission and reception
2
25MarineTech Project, Lean Institute ODU, May 2011
12. Unit Conversions
1 Metric ton = 2204.62 pounds = 1000 kilogram
1 long ton = 2240 pounds = 1016.05 kilogram
1 meter = 3.281 feet
1 knot = 1.151 miles / hour = 1.852 kilometer / hour
1 nautical mile = 1.151 miles = 1.852 kilometer
746 horsepower = 1 Watt = 1 Joule / second
26MarineTech Project, Lean Institute ODU, May 2011
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation
Ship Disaster Case 1
MV Safesail, a 199 meter 9500 ton DWT cargo ship sank on its maiden voyage across Atlantic,
130 miles off the Virginia coast on June 25. Three out of 25 crew members were rescued, who
witnessed the sinking of the ship. They told that the ship encountered heavy seas, listed
dangerously to starboard and capsized.
Seaworthy shipping company, owner of the MV Safesail issued a press release saying that apart
from the 5267 tons of trash for recycling, the ship was carrying 60 trailer-trucks and 3000 cars
across the Atlantic. Rescued crew members were quoted saying that the cars were loaded on the
top 3 decks and were not secured with the chains to the deck.
Many questions are being raised on the tragic disaster by the families of the deceased crew
members. Preliminary reports said that the vessel had faulty design; it was overloaded and
improperly loaded.
Specifications of the ill-fated vessel:
Length: 199 meter
Width: 32 meter
Draft: 9 meter
Cargo carrying capacity: 9500 ton
Standard tractor-trailer weight: 8 ton
Standard car weight: 1.5 ton
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation
Ship Disaster Case 2
220,966 DWT oil tanker ship MV Ölsee en-route to Japan sank 250 miles off the Alaskan coast
on June 6 after colliding with iceberg causing major threat to flora and fauna in the surrounding
region because of the oil spread.
According to the initial information received, the tanker was carrying 90,000 tons of crude oil.
The heavy Alaskan seas caused excessive rolling due to which the vessel lost control and
collided with the iceberg.
An inquiry has been ordered into the disaster. SDIA agents will investigate the disaster and
submit the report to the Seaworthy shipping company, the owner of the ill-fated ship.
Specifications of the ill-fated vessel:
Length: 287.25 meter
Width: 50 meter
Draft: 28 meter
Cargo carrying capacity: 220,966 ton
Hull Type: single hull (Mono-hull)
Longitudinal Bulkheads (along the length of ship) = 0
Transverse Bulkheads (along the width of ship) = 10
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation
Ship Disaster Case 3
MV Chemstar, 182.9 meter single hull chemical tanker ship broke apart southeast of Nantucket
Island, Massachusetts on December 15, causing one of the largest chemical spills in the history.
She was carrying Trochlorotrifluoroethane in the first three tanks and petroleum ether in the tank
number 5, 6 and 7. The ship reported excessive rolling and pitching due to heavy seas. Distress
call also reported cracks developed in the hull near tank number 4.
Specifications of the ill-fated vessel:
Length: 182.9 meter
Width: 32.2 meter
Depth: 20 meter
Draft: 12.18 meter
Total volume of chemical tanks: 52,969 cubic meters
Density of Trochlorotrifluoroethane: 1564 kg / cubic meter
Density of Petroleum ether: 640 kg / cubic meter
The above figure shows layout of MV Chemstar
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation
Ship Disaster Case 4
On 8 January 2005, a submarine “Deep Blue Ocean”, while on its way to a deep sea research
mission in the North Pacific Ocean, ran aground, approximately 350 nautical miles South of
Guam in the middle of the East Marianas Basin. This submarine is owned by amateur
oceanographers in the U.S. The incident reportedly caused death of one sailor and critical
injuries to 23 of the submarines crew and oceanographers.
Deep Blue Ocean, while transiting at the flank (maximum) speed of 35 knots and submerged to
525 feet, hit a seamount. Primary information reveals that the navigation officer made a serious
mistake in the calculation of position of the seamount.
An inquiry has been ordered to investigate the incidence. SDIA agents will find the causes
behind the incidence.
The operating conditions at the time of incidence were reported in the log book.
Water temperature: 450
F
Salinity of water: 34 parts per thousand
SONAR log showed that the time between transmission and reception of signal before an
accident was 2 seconds. The orders for changing the path of the vessels were given 10 seconds
after the detection of seamount. This submarine requires 150 seconds to change its path. The last
entry in the SONAR log for the distance of seamount was 3023 meters.
MarineTech Project Ship Disaster Investigation Lean Institute ODU May 2011
Ship Disaster Investigation Report
Write N.A. if data is not given
Ship Specifications:
1) Length of ship (in meters) =
2) Height of ship (in meters) =
3) Beam of ship (in meters) =
4) Type of ship – Cargo / Container / Oil tanker / Cruise / Chemical Tanker Ship
5) Cargo carrying capacity (in tons) =
Real Time Data (at the time of disaster):
1) Date of the disaster:
2) Actual cargo weight at the time of disaster (in tons) =
3) Type of cargo the ship was loaded with =
4) Weather conditions =
Reason/s for the disaster (one or more reasons may be present):
Reason 1:
Reason 2:
MarineTech Project Ship Disaster Investigation Lean Institute ODU May 2011
Reason 3:
Any other factors (if any) that contributed to the disaster:
Any suggestions for improvement
a) safety in ship operations and / or
b) ship design and / or
c) ship construction
Prepared by:
1) Agent ____________________________
2) Agent ____________________________
3) Agent ____________________________
4) Agent ____________________________
Date:
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation Report
Answer Key – MV Safesail (Case 1)
Ship Specifications:
1) Length of ship (in meters) = 199
2) Height of ship (in meters) = Not mentioned
3) Beam of ship (in meters) = 32 (width)
4) Draft (in meters) = 9
5) Type of ship – Cargo / Container / Oil tanker / Cruise / Chemical Tanker Ship
6) Cargo carrying capacity (in tons) = 9500
Real Time Data (at the time of disaster):
1) Date of the disaster: June 25
2) Actual cargo weight at the time of disaster (in tons) = 5267+60*8 + 3000*1.5= 10247
3) Type of cargo the ship was loaded with = cars, tractor-trailers, trash
4) Weather conditions = heavy seas
Reason/s for the disaster (one or more reasons may be present):
Reason 1: Overloading
The ship was carrying 3000 cars, 60 tractor-trailers, and trash for recycling at the time of
disaster. Each car weighs 1.5 tons and a tractor-trailer weighs 8 tons. In addition to this she was
carrying 5267 tons of trash for recycling. The total weight of cargo at the time of disaster was
10,247 tons. This is 747 tons more than the cargo carrying capacity of the ship. This overloading
contributed to the sinking of MV Safesail.
Reason 2:
The cars on the top 3 decks were not secured properly to the decks. The excessive rolling due to
the heavy seas caused these cars move toward starboard. This changed the position of center of
gravity substantially to the right side of the ship. Eventually ship lost control and capsized.
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Any other factors (if any) that contributed to the disaster:
Any suggestions for improvement
a) safety in ship operations and
b) ship design and
c) ship construction
The cargo should be properly secured on the deck.
A ship should not be overloaded.
Prepared by:
1) Agent ____________________________
2) Agent ____________________________
3) Agent ____________________________
4) Agent ____________________________
Date:
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation Report
Answer Key – MV Ölsee (Case 2)
Ship Specifications:
1) Length of ship (in meters) = 287.25
2) Height of ship (in meters) = Not mentioned
3) Beam of ship (in meters) = 50 (width)
4) Draft (in meter) = 28
5) Type of ship – Cargo / Container / Oil tanker / Cruise / Chemical Tanker Ship
6) Cargo carrying capacity (in tons) = 220,966
Real Time Data (at the time of disaster):
1) Date of the disaster: June 6
2) Actual cargo weight at the time of disaster (in tons) = 90000
3) Type of cargo the ship was loaded with = Crude Oil
4) Weather conditions = heavy seas, iceberg
Reason/s for the disaster (one or more reasons may be present):
Reason 1: Partially loaded ship
The ship was carrying 90,000 tons of oil. The cargo carrying capacity of the ship was 220,966
tons. So the oil tanker was partially loaded. Free surface comes into picture in case of partially
filled tanker ships. The ship did not have longitudinal bulkheads. (Longitudinal bulkheads are
used to reduce free surface effect). Absence of longitudinal bulkheads and partial loading of the
ship caused excessive rolling in heavy Alaskan seas, ship lost control over its direction and
collided with an iceberg.
Reason 2:
The ship had a mono-hull (single hull) design. The ship could have survived, if had a double
hull. Double hull increases damage stability and also prevents oil spillages.
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Any other factors (if any) that contributed to the disaster:
Any suggestions for improvement
a) safety in ship operations and
b) ship design and
c) ship construction
Tanker ships should have double hull.
Tanker ships never sail partially filled, if so proper ballasting should be
done.
Prepared by:
1) Agent ____________________________
2) Agent ____________________________
3) Agent ____________________________
4) Agent ____________________________
Date:
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation Report
Answer Key – MV Chemstar (Case 3)
Ship Specifications:
1) Length of ship (in meters) = 182.9
2) Height of ship (in meters) = 20 (depth)
3) Beam of ship (in meters) = 32.2 (width)
4) Draft (in meters) = 12.18
5) Type of ship – Cargo / Container / Oil tanker / Cruise / Chemical Tanker Ship
6) Cargo carrying capacity (in tons) = Not mentioned
Real Time Data (at the time of disaster):
1) Date of the disaster: December 15
2) Actual cargo weight at the time of disaster (in tons) = 50033.004
3) Type of cargo the ship was loaded with = Chemicals
4) Weather conditions = heavy seas
Reason/s for the disaster (one or more reasons may be present):
Reason 1: Improper Loading
The ship was carrying trichlorotrifluoroethane and petroleum ether at the time of the disaster.
Petroleum ether was loaded in tank numbers 5, 6 and 7. Trichlorotrifluoroethane was loaded in
tanks 1, 2 and 3. This means tank number 4 was empty.
Total volume of chemical tanks was 52,969 cubic meters, so volume of each tank comes out to
be 7567 cubic meters. Total volume of trichlorofluoroethane was 7567*3 = 22701 cubic meters.
Density of this chemical is 1564 kg / cubic meter. We can calculate weight by using formula
Density =
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Mass = Density * Volume. So mass of trichlorotrifluoroethane was 35,504,364 kilogram. Using
same equation, mass of petroleum ether comes out to be 14,528,640 kilograms. This clearly
indicates that there was weight imbalance in the ship. The ship was loaded heavily in the front
half. This weight imbalance caused excessive pitching in heavy seas conditions. Excessive
stresses were developed in the mid hull section near tank number 4.
Reason 2: Single Hull
The ship had single hull (mono-hull) design. Tanker ships have double hull design to prevent
spillages in case of accidents. But MV Chemstar had a single hull which failed in heavy weather
due to excessive stresses.
Any other factors (if any) that contributed to the disaster:
Any suggestions for improvement
a) safety in ship operations and
b) ship design and
c) ship construction
Tanker ships should have double hull design.
Special care should be taken during loading 2 or more cargos having
different densities.
Prepared by:
1) Agent 1 _________________________________
2) Agent 2 ________________________________
3) Agent 3 ________________________________
4) Agent 4 ________________________________
Date:
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
Ship Disaster Investigation Report
Answer Key – Deep Blue Ocean (Case 4)
Ship Specifications:
1) Length of ship (in meters) = Not Mentioned
2) Height of ship (in meters) = Not Mentioned
3) Beam of ship (in meters) = Not Mentioned
4) Draft (in meters) = Not Mentioned
5) Type of ship – Submarine
6) Cargo carrying capacity (in tons) = Not mentioned
Real Time Data (at the time of disaster):
1) Date of the disaster: January 8, 2005
2) Actual cargo weight at the time of disaster (in tons) = NA
3) Type of cargo the ship was loaded with = NA
4) Weather conditions = Not Mentioned
Reason/s for the disaster (one or more reasons may be present):
Reason 1: Mistake in the calculation
The operating conditions at the time of incidence were reported in the log book.
Water temperature – 450
F
Salinity of water – 34 parts per thousand
SONAR log showed that the time between transmission and reception of signal before an
accident was 2 seconds.
The navigation officer made a mistake in the distance calculation.
Using following formula we calculate the speed of the sound at the depth of 525 feet (operating
depth of the submarine)
Speed of sound = 4388 + (11.25 × temperature (in °F)) + (0.0182 × depth (in feet) + salinity (in
parts-per-thousand)).
Speed of sound at 525 meters and at given water conditions is 4959.6 feet per second
(1511.61 meters per second)
Taking the time between transmission and reception of the SONAR signal into consideration the
MarineTech Project Ship Disaster Investigation Lean Institute, ODU May 2011
distance of the seamount from the submarine can be calculated by the following formula.
Distance =
We have 2 in the denominator because, the time between transmission and reception is the total
time taken by sound waves to reach object and come back.
Distance of seamount = 1511.61 meters.
But the navigation officer calculated the distance wrongly. His answer was double that of the
actual distance, which proved fatal.
At the time of detection of Seamount
Actual distance from Seamount = 1511.61 m (navigation officer calculated 3023 m)
Speed of Deep Blue Ocean = 18 m/s
At the time of detection of Seamount
Actual distance from Seamount = 1511.61-10 x 18 = 1331.61 m
(since order for the direction change was given 10 seconds after the detection of
Seamount, submarine had traveled 180 meters in the mean time)
Deep Blue Ocean required 150 seconds to change its course completely. So in terms of distance
it required minimum 150 x 18 = 2700 meters to change its course; but actual distance available
was 1331.61 meters only.
Serious error in calculation led Deep Blue Ocean to disaster.
Any other factors (if any) that contributed to the disaster:
Any suggestions for improvement
a) safety in ship operations and
b) ship design and
c) ship construction
Prepared by:
1) Agent 1 _________________________________
2) Agent 2 ________________________________
3) Agent 3 ________________________________
4) Agent 4 ________________________________
Date: