Life Raft Release System and Launching Procedure

- Apr 21, 2018-

As discussed in the previous article, life raft has an advantage over life boat as they are easy to launch and during emergencies, the life raft inflates itself automatically as soon as it comes in contact with seawater. In this article, we will discuss the life raft release system and launching procedure.

The life raft on board ship are released or launched in to the water by three different methods:

1)      Auto release with Hydrostatic Release Unit (HRU).

2)      Manually launching.

3)      Launching by Davits.

Auto Release with Hydrostatic Release Unit (HRU):

The life raft HRU plays an important role when it comes to saving life during 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.

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.

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.