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Inflatable Life rafts are provided as a life-saving appliance on every seagoing ship, in addition to the lifeboats.
Life raft is much easier to launch compared to lifeboat and in case of emergency situations, evacuation from the ship can be done without manually launching any of them as the life rafts are designed with an automatic inflatable system.
SOLAS Chapter III gives all the details for types and the number of life rafts to be carried as per the dimension and type of the ship.
Where Are Liferafts Located On Ship?
SOLAS Life rafts are normally located on muster station, on port and starboard side near to the lifeboat, and fwd and aft of the ship.
Inflatable Life raft is stored in a GRP container, incorporated with a high-pressure gas used for inflating life raft at the time of emergency.
A Hydrostatic Release Unit (HRU) is connected to raft container and ship, which release the raft even after the ship sinks in water.
The particulars of the raft are stencilled on the container which includes the capacity, manufacturing date, servicing date, company name etc. along with the launching procedure with a photogenic display for easy understanding.
The basic survival items are already stored in the raft which includes rations, drinks, signal, knife etc.
Some ships carry a davit launching system which allows the crew to inflate and board the liferaft on the deck, avoiding the risk of going into the seawater. It's more friendly for the old people and children.
Important Solas Requirements For the Liferafts
All liferaft provided on ships should be bestowed with its painter permanently attached to the ship
It should inflate automatically when the ship sinks.
Liferafts should be stowed in such so as to permit the manual release of one Liferaft or container at a time from the securing arrangements.
Davit-launched liferafts should be stowed within reach of the lifting hooks
Liferafts intended for throw-overboard launching should be stowed so as to be readily transferable for launching on either side of the ship
Servicing of Liferafts
All liferafts shall be serviced:
-at intervals not exceeding 12 months (if impracticable, the administration may extend this period to 17 months)
-at proper service stations with proper servicing facilities and trained professionals.
Davit-launched liferaft automatic release hooks should be maintained in accordance with instructions for onboard maintenance.
Important Requirements for Life Rafts
The liferaft of any type of ship needs to follow the regulations mentioned in SOLAS. Some of the important points regarding liferafts 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 metres, 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
Can be towed at 3 knots with its full equipment, compliment 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 shall be provided with a means of collecting rainwater
It shall be provided with a means to mount a SART at a 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
Minimum carrying capacity must be at least 6 persons
The life raft shall be fitted with an efficient painter of length equal to minimum 10 metres plus the distance from the stowed position to the waterline in the lightest seagoing condition or 15 metres, 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 a period of at least 12 hours
When the liferaft 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
Inflation is done by CO2 with a small quantity of N2 which acts as an anti-freezing element. Also, CO2 is non-flammable and also weighs more than air hence adds buoyancy to the raft. The freezing point of CO2 is -78 degrees so it can inflate life raft at really low temperatures
Location on a ship:
– 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)