how do cats handle big waves?

Discussion in 'Multihulls' started by Guest1578132542, Jul 15, 2010.

  1. mark775

    mark775 Guest

    Lower dridge deck/ raise bridge deck.
    One thing that gets me about these animals is when the designer does this:


    As if the little tit in the middle is going to somehow displace a wave (to where?)
  2. Gary Baigent
    Joined: Jul 2005
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    Gary Baigent Senior Member

    Another war story. On my very light, fine bowed 32 foot Bamboo Bomber catamaran Supplejack with a 30 inch chord wing mast I was single handing from Kawau to Auckland with a very hard Easterly blowing astern; SJ had no sail up; I did run with the jib from the island for awhile but got hit by two huge surf waves off Moturoa (there must be some shallow reef there) that encouraged me to drop even that small sail area. Even so the boat was sailing very fast. Later I caught a fleet of half a dozen keelboats approaching A buoy and the channel, tide still running out and wind against it when the boat went up on this very large wave and started to round up. I had the helm hard up trying to bear away and the boat was slowly doing that, my other hand holding some rope to stop me flying down the trampoline, which seemed near vertical but probably was around 65 degrees - the leeward hull was completely beneath white water, buried, you couldn't see anything of it, just the beams disappearing into white and yet the boat was still turning away. Now I was right in the middle of the keelboats and everyone one of them had broached too and was flattened with spreaders in water. SJ survived but I'm sure had I been carrying sail I would have been swimming in froth. Past Rangitoto light the wind funneled even harder but the sea was flatter and SJ was making an estimated 20 knots up harbour, no sail, a wonderful feeling.
  3. Boston

    Boston Previous Member

    Holly smokes Mark is that yours

    dam nice boat there mate
    I am impressed


  4. mark775

    mark775 Guest

    You know, Bos, I am not much of a sailboat guy (I'm getting to be more of one with age but just for local fun - not for serious passages, having seen too many "...As idle as a painted ship...Upon a painted ocean" or "Tyrannous and strong" ...but having been about that one, I'd take 'er!
  5. Boston

    Boston Previous Member

    not your boat eh

    I kinda pictured you in a nice pilot house with a microphone and a few decks of tourists eagerly awaiting something.
    but that sailor was really nice
  6. Chris Ostlind

    Chris Ostlind Previous Member


    Do you have any idea as to what that design element is designed to do for the boat?
  7. mark775

    mark775 Guest

    Okay. I'll bite. Enlighten me.
    Please don't say "to turn the spray downward to increase lift", "to cut thru the waves", "to add stiffness", "to eliminate interferance between hulls" or "to soften wave impact" because the design element can have one purpose and that is known best to the marketing department.
  8. waikikin
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    waikikin Senior Member

  9. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Hi Dung B, I used to have a cat from Beach Marine, the underwing only started at the mast beam- forward of this was a woven rope trampoline(little resistance to wave), the underwing clearance was about 600mmm but only about 1400mm long with a nicely angled entry & cut up to much greater clearance aft, in seven years of living aboard/weekends/cruising the underwing copped a few heavy hits but only a few- there was a lot right about this boat, the greatest windspeed I saw on it was gusting to 72 knots- I didn't want to be there then but she saw us through fine running away under bare poles at around 8K- I sailed to weather in up to 45K under reefs & driving hard with leeward hull being swept with green wavetops.
    A lot comes down to the vessels design & how you handle it, I made my share of mistakes as we all do in my multi learning curve & she forgave them as a boat will do to a point- you have to decide that point.
    Regards from Jeff
  10. Bruce Woods
    Joined: Sep 2007
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    Bruce Woods Senior Member

    Maybe I can offer a little insight. We try and avoid sailing beam on to nasty breaking seas as the "slam" of a breaker hitting the high slab sides of a cruising cat certainly piques one attention. The arguments one hears about centreboard cats being safer than mini keels in this situations are certainly placed in perspective when the boat gets walloped from side on. Waves move pretty damn quick. The vessel needs to be strongly built irrespective of what you have in the water, a long slim slab-sided cat hull provides heaps of resistance in itself.

    The hardest point of sail in a cat in waves and strong winds, is to make way to windward in a reasonably orderly fashion. ie with fully reefed main and storm jib, its very difficult to to stop the bows from being blown off to leeward as one falls off the back of the seas, yet still creep along at a speed that allows life to continue onboard.

    A mono would always be my first choice for a high lattitude westward circumnavigation. Nothing performs on a reach and at anchor like a cat, that is what sells it to us.
  11. rayaldridge
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    rayaldridge Senior Member

    Mark, maybe I missed it, but have you ever been out in big seas in a well-designed cruising cat?

    If not, I can't see how you can honestly claim that "I have far more experience in this than any of you, seriously...."

    I'm not one of them, but many of the multihull people on this forum have an awful lot of sea miles in their logbooks, some in truly terrible conditions.

    You seem to be basing your opinion on an anecdote of limited scope. Let me give you another. Back in the 70s, the late great designer of small multis, Thomas Firth Jones and his wife sailed from the east coast to Bermuda in a modified Wharram Hinemoa. This is a very small cat to be out on the ocean-- stability increases much faster than length, and Two Rabbits was only 19 feet on the waterline, so had only a tiny fraction of the stability a 40 foot cruising cat would have. As they were returning from Bermuda, they were caught in a hurricane, and the eye passed very near to them. At one point, they were seen by a brand new, well found Dutch yacht called Banjo. Later that night, Banjo fell off a wave and split open. The crew managed to keep the yacht afloat long enough to be rescued, but of course, the yacht was lost. Two Rabbits survived without damage, and Jones and his wife returned to the mainland without any further difficulty.

    In all honesty, do you really think your experience in the tide rip was a test anything like the survival of a hurricane at sea?
  12. rayaldridge
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    rayaldridge Senior Member

    I don't think it's absolutely essential that a cat have high slab sides, or that it be less able than a monohull to windward. In fact, a good cat should be better to windward than a good monohull, except in drifting conditions, when wetted surface will hurt the cat.

    Look at a Shuttleworth cat, for example-- the hulls are anything but slab-sided.

    As to windward ability, I can offer a modest anecdote. When I was drawing my 16 foot beachcruising cat Slider, windward ability was much on my mind, because it's about 5 miles SE from our slip to the nearest pass to the Gulf, and prevailing winds are from the SE. So I made an effort to optimize the boat for windward ability. In the recent Florida 120, a raid-type event for small boats, the first two days were to windward in heavy air, and though the waters are protected by the barrier islands, the fetch meant there was a big chaotic chop. The only boat in the fleet faster to windward than Slider was a 30 foot monohull based on the peapod-- a really terrific boat, and the longest in the fleet. This was a great surprise to me, because Slider is undercanvassed for a multihull.
  13. mark775

    mark775 Guest

    Hey Ray, I have fished in hurricane force winds. I crewed on a halibut schooner and pulled 43,000 lbs. of halibut almost myself in a 24 hour period when the wind never got below sixty (the other deck crew were injured). I haul cargo on a 50M landing craft with a flat gate up front in these winds. I stood on the wall of the wheel house on a 35M research ship near the Trinity Islands becaused it was healed that far. I have been on that ship in Amchitka Pass when all 14 crew but me were puking and some were crying in fear. There is not a winter when I don't see 100 MPH. When you cannot see a 50M tugboat painted RED less than two boatlengths away because of spray, your 120MPH rated RADARS both knocked out long ago, tell me about these people on a little cat (I have been there trying to keep a stupid tanker from making another spill). I believe that llittle cat would pinwheel like an inflatable liferaft in these winds (you didn't even know that liferafts do that in high winds, did you?) If you want to relate sea stories, at least talk of the Beaufort scale. For the size/type of boat I was in the other day, it was the worst conditions I have ever been in (and only maybe eighteen knots of wind!) and only one of four times bad enuf to scare me (the other three were all human error, as well, mind you). Part of the problem is lubbers, or near-lubbers, exaggerate sea-state and windspeed. I'm not willing to do that so my measly twelve footers don't sound like much. It doesn't matter much to me, like I said before, my goal here is to educate and learn from others but really, not very many others can relate to what I do. If you will, teach me about cat design or explain to me how well they can make steerageway in violent **** (I'm not talking "choppy"). Sorry, sailboater tourists and their hurricanes don't easily impress me! I'm sure some of the folks have seen some stuff but I have seen it and heard too many stories...
    No, I do not have much cat experience - only a Hobie when I was young and three power cats on just choppy days here. I will say that the displacement power cat seemed far better than the other two.
  14. mark775

    mark775 Guest

    Between my stalker and the animosity I have seemingly nurtured with my obvious rough weather aversion to light boats (including mine), in general, and cats, in particular, I think it best to leave the thread to you cat people. Enjoy.

  15. Westernman51
    Joined: Jul 2010
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    Westernman51 Junior Member

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