Life Raft Release System and Launching Procedure
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 into 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 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.
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.
Disclaimer :
The information on this website is for general purposes only. While efforts are made to ensure accuracy, we make no warranties of any kind regarding completeness, reliability, or suitability. Any reliance you place on such information is at your own risk. We are not liable for any loss or damage arising from the use of this website.
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Disclaimer :
The information on this website is for general purposes only. While efforts are made to ensure accuracy, we make no warranties of any kind regarding completeness, reliability, or suitability. Any reliance you place on such information is at your own risk. We are not liable for any loss or damage arising from the use of this website.
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About Author
An ardent sailor and a techie, Anish Wankhede has voyaged on a number of ships as a marine engineer officer. He loves multitasking, networking, and troubleshooting. He is the one behind the unique creativity and aesthetics at Marine Insight.
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Myself I am working as a mariner, after i read this article, I am very happy to know all those basic things. Really it is so knowledgeable and super.
very very gd description for Life Raft Release System and Launching Procedure to preserve the human life if any emergency by gd knowledge.
Thanks & Regards,
Subodh Kumar
very good website
Excellent very informative at a touch of a button.Thanks
The vessel I am working on has the life rafts mounted on cradles that are designed to tip out with extensions that allow the raft to clear the side of the vessel when launched.
The USCG insists we have launching instructions posted that show this procedure.
All the info I can find show lifting the raft and throwing it over.
I am trying to find a supplier for stick on instructions to satisfy the the USCG, any help would be great.
Thanks, Grady
Myself I am working as a mariner, after i read this article, I am very happy to know all those basic things. Really it is so knowledgeable and super.
In my opinion painter should not be tied up to the ship in case the knife is accidentally drop then how can the liferaft be detached from the ship.
Hydrostatic release releases only if the ship sink.
There should have a weak link that does not depend on the hydrostatic pressure. This is useful if the ship is abandon during a fire onboard and the knife in the liferaft is accidentally drop due to panic, the weak link should be able to release the raft from the ship if cutting by liferaft knife is not possible
My opinion during manually operation the painter line is already secured then it not spouse tied at strong point . In case of emergency if you no have a knife to cut the painter after aboard you can broke it by force .
Myself I am working as a mariner @ Singapore Bunker barge , after i read this article, I am very happy to know all those basic things. Really it is so knowledgeable and super.
Very good description for Life Raft Davit Release System and Launching Procedure to preserve the human life if any emergency by good knowledge.
Best regards
Mujianto
Excellent for biginners at sea.
very educative
what is the difference between life raft Hru and epirb hur ??
This is great!
Am so happy to get the information I needed here. I’ll be glad to spread the knowledge I grabbed to personnel onboard because today is an abandon ship drill on the HD CONTENDER
Awesome 🙂
Dear wilftedo
Liferaft depending on its capacity has 2 knives with buoyant handles placed at the liferaft entrance.
How the life raft will inflate, automatically when contact with sea water or need to pull the the painter line to inflate. Iam asking after manual launching for off shore platforms
@M.Anas: For manual launching, the painter needs to be pulled to inflate the liferaft.
Thank you so much..you are giving very good information and knowledge
You have an answer to each point
All topic are well explained
@Sanchit: Thank you for your kind words and appreciation. It definitely helps the team to keep doing more.
i want to know if the HRU on a liferaft fails to activate while the vessel sink below 4m to the bottom of the sea , how will the liferaft be deployed in this case.
@Marcel: If the HRU fails, most probably the raft canister will sink with the vessel.
Great solution thank you so much
@Jaspal: ??