helocopter have emergency inflatable pontoons, why not boats?

Discussion in 'Boat Design' started by Squidly-Diddly, Aug 12, 2009.

  1. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Instead of deploying much smaller inflatable life rafts if the boat is sinking, how about deploying some inflatable tubes about the main boat?

    I figure they could be mounted as semi-permanent rubbing strakes on the hull about 1/2 from the deck to water line, with a sufficient covers to prevent damage, and would be in 8'(?)sections anyway some if a couple turned out to be damaged and useless the other 2/3 should still do the job.

    They might even be deployed in rough seas or massive extra floation is called for.

    Could you get a break on sinking insurance?
     
  2. mark775

    mark775 Guest

  3. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I never understood 'hard' inflatable-SHAPED boats.

    Some company makes hard inflatable shaped runabout yacht tender sized boats.

    I understand the value of massive puncture-proof Styrofoam flotation, but why the rounded top corners? Wouldn't that make it much harder to pull oneself from the water into the boat (which seems to be the main mission of these boats), and generally do nothing to keep water/spray out of the boat? I guess they would be comfortable enough for sitting on with your legs hanging over the side.

    "DUX" inflatable speed boat catamarans have angular keels; to me it would make more sense to make inflatables with a more traditional hard boat shape at the gunnels.
     
  4. apex1

    apex1 Guest

    If you want a rugged one lookup "No Limits" THAT is a seagoing boat. But the question of some Hypalon tubes in a pocket along the hull is not new and I think could be done. Today we have the possibility to get them proper attached to the hull and quickly inflated too. What I´m not sure about is another issue, how fast do we get rid of them in case we are in a stable inversed position?
     
  5. Squidly-Diddly
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    Squidly-Diddly Senior Member

    instead of a "pocket" I was thinking of an add-on system

    that could be bolted or otherwise fastened to any existing hull.

    Something that could also serve as a rub-strake, spray-defector and foothold until it is in needed in an emergency.

    Probably not hyponlon, which is thick, heavy and supposed to stand up to years of heavy use. I'd use whatever they use on the helicopter emergency floats. I'm not talking about the pontoons, I'm talking about the barely noticeable little bulges on helicopter's skids that are only used in a crash landing on water. A one-time-only system.

    As far as correcting a Stable Inverted position, I would think deflating one side would tend to cause the boat to become Unstable Inverted and hopefully right itself with a little help from the waves and wind.

    Mostly, I'm thinking about a system that would be unobtrusive but could still keep the boat from sinking straight to the bottom.

    I remember reading "DO NOT INFLATE LIFE RAFT INSIDE VESSEL" on an emergency life raft. I thought, 'that might not be too bad an idea, if the inflatable had enough buoyancy to keep the vessel from sinking'. Of course a life raft wouldn't have enough in most cases.
     
  6. stimulous check
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    stimulous check Junior Member

    = Religion?

    I like the idea of emergency inflated floats.
     
  7. apex1

    apex1 Guest

    A add on system would need a sufficient structural reinforcement, which is not easy to achieve! You have to handle quite hughe forces. Imagine what happens when a 60 tonnes vessel goes topside down and your tube develops a 5m³ buoyancy force!

    Regards
    Richard
     
  8. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Apex, would think a row of separate tubes along the hull

    wouldn't put too much stress on anyone place, but I have heard of some pretty thin hulls in the 'water-line to deck' region.

    Of course that area is by definition strong enough to take hard hits from waves so it would just be a matter of enough connection points, and maybe a backing plate to spread the load.

    I hear one of the great advantages of inflatables is their intrinsic ability to "roll with the punches" and dissipate energy over bigger area and timeframe.

    I think the biggest problem would be mental pain involved in putting a row of holes in an otherwise perfectly good boat, just to install some questionable new product.

    I guess any connection-point//inflatable-interface should be designed so that the inflatable could be torn-off under extreme stress without ripping the connection-point hardware out of the hull and leaving a big hole.


    Mostly, I'm wanting a system that could turn a typical motor or sail boat into a craft with the qualities of a RIB, which is the preferred rough-water rescue craft, except it would be much bigger, and deploying the inflatable collar would have the effect of making the boat suddenly ride like a much bigger boat, whether swamped or not.
     

  9. apex1

    apex1 Guest

    It is less the vessels structure I would fear, a proper done metal boat can have such reinforcements at no cost no hassle. But the rubber balloon is hard to reinforce to bear serious forces.
     
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