Re: [PCW] Manta bridgedeck clearance
As A rule of Thumb it was determined some 40+ years ago that a wing-deck clearemce of 3 feet static from the actual water line was required on Blue Water Catamarans. I was a business and design partner of Hugo Meyers at that tine.
Jerry W. Perry
Huntsville, AL. USA
jerryperry48@netscape.net
"Pat Reischmann" preischmann@msn.com wrote:
We measure the clearance from the water to the top of the bridgedeck on either side of the nacelle at the low point, of course the clearance is greater in the forward area under the trampoline. Measuring from the narrow anti-slam nacelle to the water would not provide an accurate comparison.
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Jerry Perry wrote:
As A rule of Thumb it was determined some 40+ years ago that a
wing-deck clearemce of 3 feet static from the actual water line was
required on Blue Water Catamarans. I was a business and design
partner of Hugo Meyers at that tine.
Glad to have you with us on Power Catamaran List, Jerry.
What is the waterline length of your cats? What is the distance between hulls?
Should the matter of wing-deck clearance on power cats be approached
any differently than on sailing cats?
--Georgs
Georgs Kolesnikovs
Power Catamaran World
http://www.powercatamaranworld.com
Gentlemen please; the rule of thumb is just that. The largest Catamaran we ever designed was a 68 foot motor sailer. All the cats were basically designed on a ratio of 2 to 1 or a beam of half the OAL and a hull fineness ratio of around 10 to 1. The wing deck was as on most sailing cats only ½ to 2/3s the OAL with open areas fore and aft covered with open netting. This was to prevent excessive air from being trapped under the wind deck and lifting the cat out of the water. The measured point for static clearance was usually close to the center of the cat and 3 ft or about a meter work fairly well.
Now that being said I agree that a large power cat could have a lower wing deck with a wave diverting shape and work very well, however we were more concerned as to the dynamics of the hulls movement through the water then wing deck issues. We tried to limit the amount of wetted surface and keep the cats weight down to a reasonable displacement. Reason being most of our cats would rise with the swells and wing deck pounding was never a large issue. It did occur, but usually only in conditions where there was a large short steep chop or large holes in the water like one may find in the Molokai channel some times.
Jerry Perry
-----Original Message-----
From: Georgs Kolesnikovs georgs@trawlering.com
To: Power Catamaran List power-catamaran@lists.samurai.com
Sent: Thu, 29 Sep 2005 08:35:34 -0400
Subject: [PCW] Wing deck clearance, was Manta bridgedeck clearance
Jerry Perry wrote:
As A rule of Thumb it was determined some 40+ years ago that a
wing-deck clearemce of 3 feet static from the actual water line was
required on Blue Water Catamarans. I was a business and design
partner of Hugo Meyers at that tine.
Glad to have you with us on Power Catamaran List, Jerry.
What is the waterline length of your cats? What is the distance between hulls?
Should the matter of wing-deck clearance on power cats be approached
any differently than on sailing cats?
--Georgs
Georgs Kolesnikovs
Power Catamaran World
http://www.powercatamaranworld.com
Power-Catamaran Mailing List
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