New Liprari 39 cat almost capsizes in 25k gust in flat seas.

Discussion in 'Multihulls' started by DennisRB, Jun 23, 2010.

  1. DennisRB
    Joined: Sep 2004
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    Location: Brisbane

    DennisRB Senior Member

    Story goes something like this:

    Lipari was sailing with full sail in light winds when a 25k gust hits it which causes the boat to accelerate to 10-11k. Everything seems fine besides strong weatherhelm then all of a sudden the boat simultaneously flys a hull up to 25-30 degrees and swings to windward until it is facing into the wind enough to drop the hull back down.

    See thread for first hand account.

    What the hell happened here? Is this a safe boat? Note this is a charter style cruising cat not a race boat!
  2. cavalier mk2
    Joined: Mar 2010
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    Location: Pacific NW North America

    cavalier mk2 Senior Member

    It sounds like the hull lifted with the added centrifugal force of the sudden turn. The weather helm sounds like the CE needs changing, a little less roach maybe? Someone could run the stability #'s a la Wharram. His experience may be a factor as winds of 25 knots have far more force than those of 20. On a reach he is also on a less stable course. What was his load ? Cruising stores or ? If the rudder(s) allowed he should have turned away from the wind to reduce the centrifugal force and drop the hull back down. He sort of lucked out that it wasn't the little bit more needed to flip. Oh and release the sheets!
  3. Tantalus
    Joined: Mar 2010
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    Location: Auckland, New Zealand

    Tantalus 1963 kauri cruiser

    Skipper should have turned downwind, not upwind. Reverse logic from a mono hull!

  4. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    Too much sail for the conditions - full sail in 27 kt true. He should have been reefing at ~20 kt true or apparent, whichever comes first. 27 kt produces 80% more heeling moment than 20 kt. The heavy weather helm was also a cue that he had too much mainsail.

    He was sailing at 90 deg apparent, which in that boat probably put him at about the worst possible position. Once the boat was headed up, he did the right thing to keep going in that direction, since he was basically on the dividing line between heading up and heading down to depower. If he'd tried to head down, the stalled rudders would have made it slow at best, and would have had the boat go right across the Line of Death once more.

    And I'll bet he had nobody with a hand on the mainsheet. If he'd released the main as soon as it was evident the boat was overpowered, that would have saved him, too. He was committing three sins at the same time - too much sail, hottest sailing angle, and nobody on the mainsheet.

    It sounds like it was a day sail, so the boat was probably not loaded down, either, which would have made it more sensitive.
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