deeper bow sail higher ??

Discussion in 'Multihulls' started by newoeloc, Oct 28, 2007.

  1. newoeloc
    Joined: Jan 2007
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    newoeloc New Member

    Ive got a design question say on a 36ft very light ( 1.4 tonne) shallow draught (1ft 6 inch's) catamaran , would it sail higher at say 10 knots if the draught at the bow was 1ft 2 inch's deep as opposed to say 1 inch?
     
  2. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Newoeloc, I think that kind of happens when the boats sailed, as the style of boats with skinny bows & comparitively fatter sterns tend to look to sail bow down when pushed & the "bow draft " kinda increases especially when compared to the "static" just sitting there waterline also the drive of the sail is up high & the forward part of this pushes the bows in too, I know when I push a multi hard I kinda look for the reserve left at the leeward bow & the waterline to transom "air", try to get a feel for whats ok especially in lumpy water, also I've noticed some deeper bowed & bulbed boats can tend to feel "locked" into the groove & much harder to steer when pushed, personally in regards to this I prefer the less immersion at the bow. Not really naval architecture speak(Cos I'm not) but my feelings/instinct from playing with multis at times for a few decades & the best I can do on a Sunday arvo. All the best from Jeff.:)
     
  3. newoeloc
    Joined: Jan 2007
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    newoeloc New Member

    Jeff , thanks for your quick reply .When sailing my 28ft cat in choppy seas I felt like the bows were always getting" slapped" off the wind especiallly when a series of bad ones come along , unlike longer cats sailing by that seemed to be bow down and running on railway tracks my cat was more like a rocking horse. So if I read what you have said correctly, if sailing hard into the wind for a couple of hours with a deeper" bow draft " you wont be as manouverable but you should have sailed higher (better VMG). Thats my hunch but I had a hunch that the bigger the m2 of the dagger boards the better the "Grip" Ive since read in this forum that that is not the case ,but thats another story. Thanks again Jeff .
     
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