DAR-ES-SALAAM MARITIME INSTITUTE
MARINE ENGINEERING DEPARTMENT
Bachelor Degree in Oil and Gas Engineering (BOGE1)
OGU 07101
Basic Safety at Sea
ASSIGNMENT 01
GROUP 10
NAME OF MEMBERS: PIUS YUDA PIUS - BOGE/22/013
HAFIDH SULTANI LUSAMBI
DAVID MARWA MAGOKO
ASHRAKA KASSIM KAMBUNGA -BOGE/22/077
IDAROUS ISSA MKUWILI
ABDILLAH ALI SIMAI
ABRAHMAN MWINYI YUSSUF- BOGE /22/131
ALHAJI MASSOUD JUMA- BOGE/22/104
RICARDO JOHN KAGERE -BOGE/22/091
ADAMU M SHIJA -BOGE/22/019
ABUBAKAR R KOPA -BOGE/22/110/
LECTURER: Eng. M. Mkwande
DATE OF SUBMISSION: 13/01/2022
ACADEMIC YEAR
: 2022/2023
1. What is inflatable Life raft? Discus with the sketch the three different methods of life raft
releasing or launching procedure in board into the water.
 A life raft is necessary equipment on board ships, yachts, or boats from marine
safety point of view. An inflatable life raft, as the name suggests, is a form of life
raft which allows people to fold and store it when not in use, or inflate it at the
time of an emergency. Moreover, life rafts or similar form of safety equipment are
mandatory on board sea bound vessels (except small sized recreational vessels) .
 The three different methods of life raft releasing or launching procedure in board into
the water as follows:
a. Auto release with Hydrostatic Release Unit (HRU).
The life raft HRU plays an important role when it comes to saving a life during an abandon ship
situation. SOLAS 74 clearly specify the requirements for construction and positioning of the
HRU at the life raft.
The Working of HRU:
 HRU acts as a connecting media between life raft container and ship deck, where it is
stored.
 The HRU comes in action under the pressure of water exerted on HRU when the ship
sinks below 4m of water level.
 The HRU consists of a sharp knife or chisel which is used to cut the strap lashed over the
container carrying life raft, but it still holds the painter at the weak link.
 The HRU is connected to the container through a lashing arrangement which can be
disengaged quickly by means of slip hook when launching the raft manually.
 The HRU is connected to a strong point on deck through a weak link.
 When vessel sinks, the HRU cuts the rope and the container floats to the surface of water.
 As vessel sinks further, the tension in the painter causes the life raft to inflate out of the
container.
 The tension acting on the weak link will cause it to break making the life raft free from
the ship.
 When vessel sinks, the HRU cuts the rope and the container floats to the surface of water.
b. Manual Launching Procedure of Life raft:
 Check that one end of the painter of the raft is well secured to a strong point on ship’s
deck or structure.
 Remove the lashing from the container of the raft and open the way to portable rail if
available.
 Check the ship side where the raft to be launched is clear.
 Two people should lift the container from both sides horizontally and throw the
container.
 Make sure the painter is still fixed at a strong point so that the raft should not be waved
away by waters.
 Pull the painter with a hard jerk to fire the gas bottle to inflate the raft.
 The life raft will take 20-30 sec to inflate.
 Board the life raft one by one using ladder or rope.
 Avoid sharp objects like knives, shoes and other sharp objects etc, which may damage
the raft surface.
 When everybody is aboard, after a headcount, cut the painter with a sharp knife.
c. Launching Raft by Davit:
 Open the lashing and remove the raft container from HRU by opening the manual slip
hook or bottle screw arrangement.
 Tie up the one end of the painter of raft into a strong point at deck.
 Keep the container in the open and attach the davit hook to the given eye in the canister/
container.
 Take up the raft load by davit and keep the container hanging at embarkation deck area.
 Pull the painter and inflate the raft. Have a thorough check on the inflated raft.
 Start boarding the raft without the shoes and other sharp object.
 After the boarding is completed, check the bottom is clear and release the securing lines,
if any.
 Someone inside the raft will detach the hook of the davit from the raft when tha raft is
just above the water.
 The davit operating person will board the raft either by jumping in to the sea, raft or by
other boarding means if provided.
 Cut the painter and cast away the raft from ship.
2. Discuss the lunching procedures of (a) open life boat / rescue boat (b) closed life boat /
rescue boat (c) free fall life boat.
 a) The lunching procedures of open life boat / rescue boat as follows:
Initial preparations: Make fast Toggle painter, Ship drain plugs, Remove Harbour pins, Lower
embarkation ladder, and Release gripes after senhouse slip.
Lower to embarkation deck: Lift brake gently and Lower to embarkation deck. Ship Rudder
and tiller.
Secure to embarkation deck: Make fast Bowsing-in tackles.
Boarding: Let go tricing pendants. Board when ordered to (wearing lifejacket). Sit as low as
possible and keep hands inside the boat.
Lower to water: Let go Bowsing-in tackles equally fore and aft from the boat. Lower boat to the
water.
Letting go: Release falls. Embark launching crew. Move away from the ship by fending off by
boat hook. Let go toggle painter. Start the Engines and move away from the ship minding the
hanging falls.
 b) The lunching procedures of closed life boat / rescue boat as follows:
Initial preparations: Make fast Toggle painter, Ship drain plugs, Remove harbour pins,
Disconnect electrical charging cable, Bring in EPIRB and SART, Board (wearing a lifejacket)
when instructed, sit and fasten seat belts.
Preparation for launching: Release gripes. Secure hatches. Open vents if in a safe atmosphere,
Close vents if in a dangerous atmosphere.
Lower boat to water: Check that there is no obstruction below the boat. Release the brake by
pulling the handle inside the boat. Release gently to avoid jerks. Lower at constant speed.
On landing in water: Keep the brake open until the falls are released. Release the falls. If falls
do not disengage, operate emergency release by breaking the glass. Move the lever to green zone
and release the falls.
Letting go: Open-air supply and water spray valves if in a dangerous atmosphere. Start the
Engine Release toggle painter when ready to move. Steer the boat away from the ship.
 c) The lunching procedures of Free Fall lifeboat :
In Free fall lifeboat, the launching mechanism is similar to on load release. the only difference is
that the freefall lifeboat is not lowered till 1m above water level, it is launched from the stowed
position by operating a lever located inside the boat which releases the boat from rest of the davit
and boat slides through the tilted ramp into the water.
3. a) What is the difference between life raft and life boat .
b) Essential Requirements for life rafts and Carrying Capacity.
 a) The difference between life raft and life boat as follows:
Life raft
i.
Life boat
A life raft is shaped like a circle or Lifeboat is one of the most important liveslarge square. It can hold more people saving equipment onboard a ship, which is
than a lifeboat because of the different used at the time of extreme emergencies for
shape. It may have oars, but usually has abandoning a ship. Lifeboat is a smaller rigid
nothing to help it move. If you are on a vessel, secured onboard into davits so that it
liferaft, you usually have to wait for can be launched over the side of the ship with
rescue.
least time and mechanical assistance possible
for an early escape of the crew from the ship.
ii.
Life rafts are survival equipment A lifeboat must carry all the types of
provided as a life-saving appliance on equipment described under SOLAS and LSA
every seagoing merchant or passenger codes, which are passed for the survival at sea.
ship, in addition to the lifeboats.
This includes rations, freshwater, first aid,
compass, distress signalling equipment like
rocket etc. A ship must carry one rescue boat
for the rescuing purpose, along with other
lifeboats. One of the lifeboats can be
designated as a rescue boat if more than two or
more lifeboats are present onboard a ship.
iii.
Life rafts are much easier to launch Modern lifeboats have a motor; liferafts
than
lifeboats.
In
emergencies, usually do not
evacuation from the ship can be done
without manually launching any of
them, as the life rafts are designed with
an auto-inflatable system.
iv.
However, life rafts are strictly inflatable Lifeboats may or may not be inflatable. They
and come with auto-inflation devices can have fibreglass or wooden hull as well.
like
mechanical
pumps
or
Co2
canisters.
 b) Essential Requirements for Life rafts and Carrying Capacity:
The life raft of any ship needs to follow the regulations mentioned in SOLAS. Some of the
important points regarding life rafts are:
 The lift raft should be capable of withstanding exposure for 30 days afloat in all sea
conditions
 When dropped into the water from a height of 18 meters, the life raft and all equipment in
it will operate satisfactorily.
 The floating life raft should be capable of withstanding repeated jumps on it from a
height of at least 4.5 metres above its floor, both with and without the canopy erected
 It can be towed at 3 knots with its complete equipment, complement of persons and one
anchor streaming.
 Canopy to provide insulation and protection against heat and cold by two layers of
material separated by an air gap
 Interior to be of a non-discomforting colour
 It shall admit sufficient air for the occupants at all times, even when the entrance is
closed
 It shall be provided with at least one viewing port
 It will be given with a means of collecting rainwater
 It shall be provided with a tool to mount a survival craft radar transponder (SART) at the
height of at least 1 meter above the sea level
 It shall have sufficient headroom for the sitting occupants under all parts of the canopy
 The minimum carrying capacity must be at least six persons
 The maximum weight of its container, as well as the equipment, should not exceed 185
kilos
 The life raft shall be fitted with an efficient painter of length equal to the minimum of 10
meters plus the distance from the stowed position to the waterline in the lightest seagoing
condition or 15 meters, whichever is greater
 A manually controlled lamp shall be fitted on the top of the canopy, and the light shall be
white, and it must operate for at least 12 hours with a luminous intensity of not less than
4.3 candela
 If the flashlight is fitted, it shall flash at a rate of not less than 50 flashes and not more
than 70 flashes per minute for the 12 hours that it burns
 A manually controlled lamp shall be fitted inside the life raft, capable of continuous
operation for at least 12 hours
 When the life raft is loaded with a full complement of persons and equipment, it should
be capable of withstanding a lateral impact against the ship side at an impact velocity of
not less than 3.5m/s and also drop into the water from a height of not less than 3 metres
without damage
 CO2 does inflation with a small quantity of N2, which acts as an anti-freezing element.
Also, CO2 is non-flammable and weighs more than air, adding buoyancy to the raft. The
freezing point of CO2 is -78 degrees so that it can inflate life rafts at shallow
temperatures
 Location on a ship:
–
Forward
–
At embarkation stations on both port and starboard sides
 The painter breaking strength should be:
–
15kN for 25 people and more
–
10 kN for 9 to 24 people
–
7.5 kN Rest (6-9)
Reference:
i.
https://www.marineinsight.com/guidelines/how-to-buy-an-inflatable-life-raft/
ii.
https://www.marineinsight.com/guidelines/life-raft-release-system-and-launchingprocedure/
iii.
http://m.chinaxhmarine.com/info/release-operation-of-davit-launched-life-raft52486647.html
iv.
https://www.marineengineersknowledge.com/2022/02/launching-procedure-of-open-lifeboat.html
v.
https://www.marineengineersknowledge.com/2022/02/launching-procedure-of-enclosedlife.html