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BigCat · 15-07-2008, 13:39

If the 175 mile days were on a catamaran with a waterline length (DWL) of 36', that would have a square root of 6, and the speed relative to the DWL would be 1.29 x. The equivalent in a boat with a 25' waterline would be about 155 miles, for a 49' waterline, 217 for a 49' DWL, and the equivalent in a 64' waterline woud be 248 miles a day. So, the DWL should be considered when discussing speed.

Weight is of course, another issue. The Tobago is said to weigh 4 tons, so with a DWL of about 34', would have a DL ratio of 100. Hull beam is unknown to me, but I doubt if it is slim. So, if NordicCat can get the equivalent to 225 miles a day in 15 knots of wind, or 1.6 times the square root of the DWL (assuming a DWL of 34',) then a boat with a lower DL ratio and a waterline of 64' could get 12.86 knots x 24 =308 miles on the wind, if its rig is equally good. Of course, we can't count on 15 knots of wind, but trade winds are about that usually.

15-07-2008, 13:39	#7
BigCat Commercial Vendor Join Date: May 2007 Location: Seattle area Boat: Building 65' catamaran Posts: 765	Factoring in the DWL, we can adjust speed expectations If the 175 mile days were on a catamaran with a waterline length (DWL) of 36', that would have a square root of 6, and the speed relative to the DWL would be 1.29 x. The equivalent in a boat with a 25' waterline would be about 155 miles, for a 49' waterline, 217 for a 49' DWL, and the equivalent in a 64' waterline woud be 248 miles a day. So, the DWL should be considered when discussing speed. Weight is of course, another issue. The Tobago is said to weigh 4 tons, so with a DWL of about 34', would have a DL ratio of 100. Hull beam is unknown to me, but I doubt if it is slim. So, if NordicCat can get the equivalent to 225 miles a day in 15 knots of wind, or 1.6 times the square root of the DWL (assuming a DWL of 34',) then a boat with a lower DL ratio and a waterline of 64' could get 12.86 knots x 24 =308 miles on the wind, if its rig is equally good. Of course, we can't count on 15 knots of wind, but trade winds are about that usually.