Emergency Flotation using Blowup Balloons

Discussion in 'Materials' started by owene, Dec 1, 2017.

  1. owene
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    owene Mr Owen Charles

    Might seem like a long shot but given the space constraints on a 40' motor launch, has anyone any experience of this idea? Obviously there would need to be some degree of safeguards involved like only being able to inflate them manually with a human-operated valve.

    But say you hit a log or a container 10 miles offshore and sustain a sinkable hull hole. In order to at least keep the vessel afloat, in my case I'd need about 10 cubic metres of flotation (10 tons). So I leave the cabin area, open the valve and a 10 cubic metre balloon/s blows up. The vessell would never then sink and the chances of being saved would be much higher.

    Be interested to hear if anyone has done anything like this - Mrs Google talks about 'boyancy units' but they all look like less than 1 cubic metre bags. Mr Google wisely says even less about the subject.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Sounds feasible, but there would be a number of things to consider, like how they are attached to the boat, how they are distributed in the boat, whether they could be inflated evenly all at once, etc.
     
  3. owene
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    owene Mr Owen Charles

    Inside the cabin with no way to escape. One big cluster of baloons to simply fill the cabin once one had escaped and shut the doors. Prob need a small bottle of argon or even CO2.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Well, if something busts open and they start popping out, all bets are off. I think you need assurance nothing can go awry, and particularly the boat does not go out of balance and tip over. Still, the idea has merits.
     
  5. Ike
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    Ike Senior Member

    The cabin structure has to be able to support the submerged weight of the boat. Not many cabin roofs are strong enough. However, it has been done, but not very often. Large bladders are used to float sunken vessels, but usually there are large straps that go under the hull and the bladders are on the outside of the hull so that the boat isn't wrecked by the forces involved.
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Yes, free-floating buoyancy bags could easily rip the boat apart. It needs more than a hit-and-hope approach.
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    I still like the idea, it is in the same vicinity as self-inflating life vests, which enables you to operate unencumbered by bulky life jackets. It is often impractical to have large volumes in a boat taken up by buoyancy chambers.
     
  8. TANSL
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    TANSL Senior Member

    In some types of ships, such as those of passage, and in some cases depending on their length, the ship must be made so that, even if it has one or two compartments flooded, the ship does not sink. This is achieved through the corresponding compartmentation of the ship. Would it be possible to do this with your boat?
     
  9. owene
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    owene Mr Owen Charles

    Not really. The design is a Hartley and the stringers are NOT rebated into the frames so as to allow free air/liquid flow right thru the bilges. Having had many of these before, I can sya that they are very dry and airy. To seal on compartment off would be impracical.

    But points above re cabin structure all understood. The abin will be built structurally capable of carrying the load. The comment re the cabin being 'exploded' out by excess force is noted - could be dealt with by a controlled amount of gas, ie only sufficient to inflate the balloons. However sharp objects and other things in the cabin might cause damage to the bladder.

    Which raises another idea, attach them to the outide of the hull and somehow camoflage them. Or even on the decks? Mmmm much thinking to do here.
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    Whatever flotation means is applied, you don't want a swamped vessel with you being in the still floating boat, but in the water inside it. Certainly not outside the tropics. It is not so much "explosive" force that will bust the cabin structure, just the fact the weight of the boat transfers to the cabin structure. You want those "balloons" attached low down inside, to structural members.
     

  11. dinoa
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    dinoa Senior Member

    Look at pop out floats as used on helicopters for inspiration. Also some RIBs have floats that are plumbed to an on board compressor. Maybe pop out floats lashed to the shear strake with a protective cover. Some RIB style rescue boats have relatively small permanently inflated floats.
     
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