Crowther 40 cat

Discussion in 'Multihulls' started by Contorta, Mar 31, 2011.

  1. bad dog
    Joined: Apr 2009
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    Location: Broken Bay, Australia

    bad dog bad dog

    Minor point - the blunt bow shape was fave of Lock's during the 80s. My mate's Crowther 48 was Lock's own boat previously (Deguello, now in Hobart), to which Lock added 300mm? to the bows to fine them up. It didn't hobby horse, so bulbs were never considered.
     
  2. Contorta
    Joined: Mar 2011
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    Location: Prince George, BC

    Contorta Junior Member

    Thanks for your input Bad Dog. Point well received :D. Was 300mm enough? Did he retain plumb bows? My design has an inboard to outboard cant at the bows. How did that turn out, if it existed on your boat?
     
  3. bad dog
    Joined: Apr 2009
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    Location: Broken Bay, Australia

    bad dog bad dog

    I'm guessing 300 - may have been more, but essentially it was just a projection of the topsides to fine entry of about40mm radius. The bows retained the classic Crowther canted lines, and they had a forward rake of about 15°. There are some nice views of the bows AT THE START of this video - but ignore the rest of it!
    http://www.youtube.com/watch?v=yGjWmFqXRhs
     
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  4. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    Get the water down low

    I would certainly not get the water up high unless absolutely necessary. I would put it under the floor where it belongs. You can still put it along station six to locate the weight in the correct longitudinal position but get it low. The under floor areas are pretty huge if I remember so it would be a great spot to put water. Chain and genset have to go up high.

    I have daggerboards and like them but don't think end plates on the end of the keel would do anything - its a concept called rudder volume (although in this case not for a rudder) Any foil can have its ability to work well quickly worked out by multiplying its area by the length of arm from the centre of gyration. Area times length = volume. The volume of a keel end plate would be miniscule as the lever arm would be tiny. The obvious way to assist is to put the end plate on the rudder. This is what Hitchiker designer John Hitch did to help with his double ender designs.

    Get the weight low and put end plates on the rudders. Get a shorter and much lighter rig and put a screecher on it for light winds. My design doesn't hobbyhorse much and the designer is fanatical about getting weight central and low down - and I have a low rig.
     
  5. Hangtime
    Joined: Apr 2011
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    Location: Australian east coast

    Hangtime Junior Member

    The plum bows are as you say.... pretty sexy and i dont want to alter them as they look so good (looks are important) I'll have to make full size templates before i sharpen em up.
    I have Daggers and like them, especialy when in shallow waters, They are heavy though, but thats just how they are if you make them out of Cedar.
    My boat had the hobbyhorsing problem before the rig went on and i approached Brett and asked for a smaller mast which was 60ft from the deck according to the plans, Mine is 55ft from the deck and there is still plenty of power there, I did lash out on the mainsail and im glad i did, Everytime i pull it up i love to look at the great shape it holds even after 22000 nautical miles.
    I had a screetcher on an endless rope furler and it was great sailing with it until off Coffs harbour last year i got caught out overpowered and tore it to shreds. it sits on a proder that swings from left to right for when running true downwind i can gring the tack to one side away from the centreline. it works well. $4000 for a new screetcher!!.
    Sitting on the Gold coast at Bums Bay right now and its a beautiful day and the locals are MAD! Screaming powerboats everywhere doing 50 knots! Jetskis and 70ft gin palaces, everyone's doing 50 knots!!
     
  6. Contorta
    Joined: Mar 2011
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    Location: Prince George, BC

    Contorta Junior Member

    Hi all, the gods are still shaking their cold dandruff on us here.
    Hangtime, I've been digesting the pictures you kindly gave me access to. It appears you have done a fine job of your boat, I hope I too can create something close to her beauty. I was getting ready to build the dagger boards and my plans call for cedar like yours, do you know if any are built of foam, like a surf board? Do you think the extra positive buoyancy would create problems? Did you use hardwood inside the hull at the forebeam attachment or a carbon/epoxy pad? I have many questions for you and I know more will develop over time; perhaps it might be better to continue by E-mail unless you think the rest of the group would benefit from our conversation, and you being willing, of course? My brother lost his genny on a furler the same way. He has a Farr 38.
    Bad Dog, I have often imagined striking a log (deadheads proliferate our coast at certain times of the year) at even 5 or 7 knots with these blunt bows, something must give and it won't be the log. I think bows akin to Deguello's might be prudent for this reason as well. Thanks for the U-tube link. Would that be 40mm radius or 40mm diameter on the bow?
     
  7. Hangtime
    Joined: Apr 2011
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    Location: Australian east coast

    Hangtime Junior Member

    Hi Contorta.
    Yes i did use hardwood backing on the forebeam attatchment point and have no probs with it at all, 24000 NM under her belly and going just fine. Im a big fan of keeping it light but using carbon here wont really matter overall i think.
    Just been cruising in an out of phone range area with 3 bikini clad backpackers so sorry for the late reply, Ive been chatting on another forum and put up some more photos that are worth a look,
    http://www.seabreeze.com.au/forums/Sailing/General/Cruising-forum/?page=1
    My email is wazhangtime@hotmail.com im more than happy to answer any questions, Help out or just talk catamaran nonsense, i'll give you my phone number via email also.
    Cheers Warren.
     

  8. Hangtime
    Joined: Apr 2011
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    Location: Australian east coast

    Hangtime Junior Member

    oh the centerboards are cedar and Heavy, my friend built foam boards for hid Schionning and they werent that much lighter ? The foam boards have much more Glass for strength where the cedar boards benefit from the grain off the wood.
    Im happy with the cedar boards and you have to ask yourself am i i building a lightweight, Expensive, Time consuming cat or a strip plank medium performance cruiser, Thats Builder friendly and not too time consuming.
     
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