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Liferaft System....?

Discussion in 'Technical Discussion' started by 84far, Oct 27, 2010.

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  1. 84far

    84far Senior Member

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    Sorry for the late reply, Didn't get the email...?

    K1W1, Marmot, I should put you two on the design team ;)

    Marmot, good call on the height restrictions and the snug cutout. I'll start to design the life rafts around the stern side gunwhale areas. There can still be a cutout (but an open top) for them to sit in (and so they don't get ripped off), but a person can also get at them from above. Due to the weight, they will be on a roller system, so easier for someone to deploy.

    Far
  2. Wanderer

    Wanderer New Member

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    The Kogo has a such a system of hidden liferafts: see http://www.acebi-yacht.com/liferaft_storage.php

    This & other similar system are very simple mechanical operations that are not really any more complex then the shiny stainless steel racks that are more commonly seen.

    There are current large build projects that are hiding away their lifeboats behind doors operated by stored hydraulic power.

    These are not radical or expensive ideas, just a question of incorporating it into a new build at the very early design stage. This can result in a much cleaner design look without any compromises to safety.

    On larger yachts that fall under Passenger Ship SOLAS rules where life-raft davits, (cranes), are required in addition to the life-rafts then a very efficient & safe alternative is an MES (Marine Evacuation System) which is commonly fitted on Ferries & Cruise ships. Done correctly this results in a very clean design & more efficient space use age. A notable example in yachting is the Al Mirqab though I cannot find a good picture to illustrate this.

    I have strayed slightly off the original topic which, presumably, was for throw-overboard life rafts. However I just wanted to illustrate that for every Life Saving Appliance requirement the yachting industry has found or adapted good solutions for making their required presence less obvious.
  3. 84far

    84far Senior Member

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    Wanderer, thank you for your post. Ideally I would love to hide the liferafts, but if a design can be made safer by returning to the old/proven ways, it would be great.

    Just a thought, but the liferafts only deploy when there under water by 4 meters... pressure release... boats like Cakewalk would have to be close to fully under to release there liferafts, is this right....? Cheers

    Far
  4. K1W1

    K1W1 Senior Member

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    Hi,

    The rafts should be able to be deployed at any time manually, the Hydrostatic releases are just in case no one got the the stowage pozzies before the vessel sinks.

    There was an 80 some meter Trawler that sunk south of NZ a few months ago, one raft and 4 souls were never found, did it get dragged down by the ship?
  5. Wanderer

    Wanderer New Member

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    IMHO & given good design concealed life rafts are as equally safe as life rafts stowed in open positions.

    KIWI is correct that the float free aspect of life raft launching is an absolutely last resort. If a +70m yacht has sunk so quickly without time to manually launch the life rafts then I am afraid there is little hope for the souls on board. The example K1W1 gives of the trawler has many possible causes. Human error in terms of lack of servicing and incorrect rigging of the hydrostatic release are are sadly fairly common and result in the life raft not being deployed.

    A final thought. The entire ethos behind the SOLAS abandon ship rules assume "dry abandonment" meaning you enter the survival craft directly from your sinking ship. With the fairly elementary yacht safety regulations requiring only the very lowest level of survival craft, (i.e. throw over life rafts) then dry abandonment in all conditions, other than near perfect weather, is unlikely to be possible.
  6. 84far

    84far Senior Member

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    Thought I would start the old thread back up again with a similar, but bigger question, this time in relation to "lifeboats".

    I've been looking at Eclipse's 13m lifeboats that she runs at her midships (both sides), and I need to know how these boats have to be operated...?

    My thought is they can be manually winched in, and/or simplely the cradle can release the lifeboat by rotating/pivoting and releasing the boat straight in (big fall)...?

    Is it also true that a lifeboat has to hang over the gunhale in such a manner that the above actions can be done, or is this a myth and a lifeboat of this size can be stalled inside a garage.

    Would love some pointers, thanks.

    Far
  7. K1W1

    K1W1 Senior Member

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    Hi,

    Lifeboats will normally be davit launched although there are also the Freefall ones usually found at the stern of the ship.

    There are rules and regulations as to how many have to be carried and at what angle of heel they must be able to be deployed, the recent Costa Concordia sinking will no doubt be causing a rethink on this one.

    I have not seen any carried inside as yet but given the wildly differing interpretation of the same written rules between Surveyors anything is possible.

    You might get a few answers by reading this: http://www.maib.gov.uk/cms_resource... lifeboat_and_launching_systems_accidents.pdf
  8. 84far

    84far Senior Member

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    Thanks K1W1, Some light reading for me :D

    I did notest the tankers ran the lifeboat from the stern with a majority running a freefall release. But as this is a pleasure vessel, I might have to stick to the midships.

    The attached image is Eclipse's layout - I'm guessing, but there seems to be a trap door above where the boat is kept, would this be where the cranes/winches a located...?

    Far

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  9. Old Phart

    Old Phart Senior Member

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    There is this version of KISS:

    Exterior Views - Yaa Kun

    Take a look at description #32, #29, and the other aerial views for a feel of the hidden, yet very accessible, perspective.
  10. Wanderer

    Wanderer New Member

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    Is is not required that lifeboats hang over the side of the vessel. Free-fall lifeboats are only allowed on cargo vessels.

    Passenger ships (& by extension passenger yachts) are all davit launched & are required to be capable of being launched against a 20 degree adverse list and within 30 minutes. There are many other requirements as K1W1 mentioned including minimum height above the water line and an easily accessible & protected muster point for guests & crew.

    If a yacht is also classed as a passenger vessel then it is highly likely that her lifeboats will serve a double function as a rescue boat, (here I refer to a true SOLAS rescue boat & not the simple inflatable rescue boat required by LY2). This brings many further requirements including a launching capability in 5 minutes.

    Therefore it is unlikely, but not impossible, that a lifeboat would be stored in a typical yacht garage.

    I do know of one large yacht under construction with gull wing doors that will totally hide the lifeboat. The entire launching process, including opening the doors, is carried out using gravity/stored hydraulic power. It is a relatively simple matter both technically & design wise to do & I suppose hidden lifeboats will be a trend on future projects.
  11. Fishtigua

    Fishtigua Senior Member

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    As large projects go, we've just done a big one for the Royal Navy's Aircraft Carrier liferaft systems for 1800 pax. Real quick exit type.

    That's the sort of jobs we do.
  12. K1W1

    K1W1 Senior Member

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    Hi,

    Fish, In case you are not aware Navies do not have to comply with 99% of the rules and regs that the rest of us mere mortals do.

    Ever read about a Naval Vessel having a PSC Inspection.?
  13. 84far

    84far Senior Member

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    Are you talking about Oceanco, I believe one of there designs (attachment below), has the Lifeboat packed away to keep it decrete. As you can see, not totally covered up, but enough to know it's there, just what the doctor ordered.

    To the drawing board! :rolleyes:

    Far

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