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Thread: Built in flotation and cabin sailboats

  1. #1
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    Default Built in flotation and cabin sailboats

    I spend 90% of my time in open sailboats - Sunfish, Argie 15, etc. So I was puzzled when I recently watched a DVD starring a mostly mute Robert Redford. Redford's sailboat got a 2 sq ft gash above the waterline, the cabin flooded with water when he inexplicably sailed it heeled the wrong way, and then sank like a rock. Huh? Isn't the area under the cabin sole supposed to be a watertight bulkhead? What about the lockers in the cockpit and other built-in buoyancy. I get that it had a big lead keel bolted on, but surely the built in buoyancy takes that into account were flooding of the cabin to occur? Which areas of most sailboats with cabins provide flotation?

    PS: One more thing about that movie -- could Redford's character please trim that jib before I lose my mind!

  2. #2
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    Default Re: Built in flotation and cabin sailboats

    Heavily ballasted keel boats sink like rocks, not likely any have that kind of flotation built in.

    Don't forget, to make a movie worth seeing and enjoying the real facts are often just kind of forgotten or altered to fit the story.

    and oh and wooo, those blue eyes RR
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  3. #3
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    Default Re: Built in flotation and cabin sailboats

    What Denise said. No the space under the floor is not sealed. Building positive buoyancy into ballasted boats would in most cases make them fairly unususable and impossible to maintain. In just a moment someone will come along with at least 5 examples of ballasted boats with positive buoyancy. But there you go.

  4. #4
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    Default Re: Built in flotation and cabin sailboats

    There was a lot wrong with that movie but one thing it got right was how up to a key point it can take a surprisingly long time for a boat to sink. But when she really goes at last, it can indeed be fast.

    Floatation in the bilge? Not hardly. Take your basic 12 ton cruising boat, maybe about 40 feet LOA. To keep that afloat you need about 400 cubic feet of air. If you're doing that by foam, you're going to fill up an unacceptable amount of accommodation.

    The notion of watertight bulkheads is the most effective. This is not done vertically, somehow baffling off the bilge where water accumulates anyway, that's what it's for. But rather watertight athwartship bulkheads. It's not unusual to see an ocean cruising boat with a "collision bulkhead" up near the bow and perhaps an equal volume bulkheaded off with the lazarette aft of the cockpit and the engine room under the cockpit. As was found in the famous Fastnet Race disaster, many boats that would really feel like they were sinking actually made it through to good weather while their crews, seeking safety in life rafts, perished.

    But mostly, if leaks are unattended, you'll sink eventually. I've been aboard three boats that would have taken maybe an hour to go down if we didn't both slow or end the intake - plugging a failed fitting, fothering the hull from outside, or daming from inside. It's just part of being a sailor to have a plan and have tools.

  5. #5
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    Default Re: Built in flotation and cabin sailboats

    PS: One more thing about that movie -- could Redford's character please trim that jib before I lose my mind!
    When that movie came out the folks over at Sailing Anarchy had a whale of a time pointing out all of the stupid sailing related things that just didn't make sense or showed total lack of any effort by the director to render the film believable to a sailor. I think the list ran to about 40 items. The director did have a very experienced consultant along, too. But apparently he didn't want to hear what he had to say. Why the attempted radio call "SOS" instead of "Mayday," and so on.
    -Dave

  6. #6
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    Default Re: Built in flotation and cabin sailboats

    Had to search for it. I had never heard of that movie.

  7. #7
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    Default Re: Built in flotation and cabin sailboats

    Despite all the nautical mistakes - why is the cabin flooding water so glassy flat while it's raging outside? - "All Is Lost" is a very good character study which I thought Redford and the director really got quite well. I had no problem suspending all my knowledge to let the story carry me along. And the seamanship they got right were nicely done.

  8. #8
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    Default Re: Built in flotation and cabin sailboats

    Isn't the area under the cabin sole supposed to be a watertight bulkhead?
    There is very little area under the cabin sole.
    There is no rational, logical, or physical description of how free will could exist. It therefore makes no sense to praise or condemn anyone on the grounds they are a free willed self that made one choice but could have chosen something else. There is no evidence that such a situation is possible in our Universe. Demonstrate otherwise and I will be thrilled.

  9. #9
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    Default Re: Built in flotation and cabin sailboats

    If you are thinking of renting or buying this film IMHO it is not the worst film of all time, just the second. It is narrowly beaten by The Horse Whisperer - there is a common factor

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