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PostPosted: Sun Jul 10, 2011 7:14 am 
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Got to wondering if a boat sailed on Utah's Great Salt Lake would be quicker than the same boat sailed on the ocean and faster still than one sailed on a lake. Seems if I float effortlessly on the salt lake and easily in the ocean and sink in a lake that a boat would float higher and have less wetted surface as well. Or is the water heavier and therefore harder to cut through? Anyone have any knowledge of this? I only have experience on the ocean/bays.


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PostPosted: Sun Jul 10, 2011 11:14 am 
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well there would be less wetted surface, but for the surface in the water there would be more drag.

so its going to come down to which has the most drag. I'm going to go out a limb here and say its going to be very diffrent from boat, to boat.


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PostPosted: Sun Jul 10, 2011 6:36 pm 
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In an absolute sense, it's true, but probably not that significant. Almost all of the components of drag increase as the square of the velocity. At the very top end, a modest reduction in drag does not generate that much more speed.

But there's a lot more going on than just wetted area reduction. The difference in viscosity changes the spray-making drag - but I've got to look that up to see whether it's significant.


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PostPosted: Sun Jul 10, 2011 7:37 pm 
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With the dense water of the GSL, winds don't build up chop and waves as high as other areas. Smooth quick sailing conditions arise with great fun. But, when large waves are produced they pack more off a punch when your going through them.


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PostPosted: Mon Jul 11, 2011 11:01 am 
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From personal experience with both a 23 foot monohull and my Hobie 16 on the Great Salt Lake, I found the monohull to be slightly faster, but more tender and no discernable difference on the Hobie. My monohull rode 2-3 inches higher in GSL than in the fresh water reservoirs. So less wetted surface and less form stability. I never got to the ocean with it to be able to see if there was a difference.


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PostPosted: Mon Jul 11, 2011 1:47 pm 
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benskiing wrote:
With the dense water of the GSL, winds don't build up chop and waves as high as other areas. Smooth quick sailing conditions arise with great fun. But, when large waves are produced they pack more off a punch when your going through them.
Agreed. The weirdest thing about visiting the Dead Sea in Israel was feeling a slight breeze on my face, yet the water surface was smooth as glass. For someone used to reading the wind on the water, it was disconcerting.


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PostPosted: Mon Jul 11, 2011 10:11 pm 
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The asymmetrical hulls of the H16 will lose a proportionate amount of lateral wind resistance due to increased buoyancy. The net result will be less forward drive. On the Dead Sea, a Hobie 16 would just blow sideways. However, a daggered boat would fly like a foiler.

I honestly have no clue - but it was fun to guess! :lol:

_________________
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1987 Hobie 16
Learning to sail.


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PostPosted: Tue Jul 12, 2011 5:26 am 
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What would you think about righting the boat in different types of water? I would think a boat flipped in fresh water would right easier than one in salt water because it sits higher and the high hull is tilted further toward the masthead. Thanks to all for their thoughts, I always gain insights which of course lead to more questions. Sailing on the GSL in high winds and getting hit by bags of rock salt....tough sledding.


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PostPosted: Tue Jul 12, 2011 9:02 am 
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ChrisD wrote:
What would you think about righting the boat in different types of water? I would think a boat flipped in fresh water would right easier than one in salt water because it sits higher and the high hull is tilted further toward the masthead.
But the masthead also floats higher in saltwater - significantly higher since the waterplane area is smaller (diagonal slice through the mast). The hull probably doesn't change that much since it's floating on it's maximum waterplane area (a slice from the deck to the keel).

It's probably not enough difference to notice, since many other factors (wind strength / waves / direction relative to the wind / technique) affect righting.


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PostPosted: Wed Jul 13, 2011 8:27 pm 
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This could only be solve with an extremely complicated formula naval engenneriers use which i can't recall the name of...
but seeing as i am studying to become a naval engeneerier one day ill be able to solve this question, till that time ill assume you'd be faster but not "noticiable"(sorry about that spelling, natural spanish speaker...)


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