I'm just as surprised as anyone. I know that 1.34 times the square root of 24.75 (Grenadine's waterline in feet) is 6.67 knots. But apparently that's only a very general rule - see http://www.boats.com/reviews/crunching-numbers-hull-speed-boat-length and https://en.wikipedia.org/wiki/Hull_speed . At 9,000 pounds displacement I guarantee I'm not planing :)
But I assume GPS doesn't lie. On June 22nd last year I was using RaceQs during a race. I forgot to switch it off after finishing, so it recorded Grenadine sailing for fun in the 25-33mph gusts that piped up after the race, under full main and 150% genoa (which tore that night, before I could get a rail in the water). If you watch this replay from 19:42:50-19:43:00 local time, you'll see Grenadine going 7.5 knots over ground according to RaceQs GPS-based iPhone app: http://raceqs.com/tv-beta/tv.htm#userId=1032518&divisionId=41508&updatedAt=2016-06-23T03:05:38Z&dt=2016-06-22T18:08:05-06:00..2016-06-22T21:05:54-06:00&boat=Grenadine I'm not one to look a gift horse in the mouth :) Maybe at 25 degrees of heel my waterline length is appreciably longer than 24.75 feet. Or maybe I just have to give credit to George Cassian, George Cuthbertson, and Rob Ball for designing a faster-than-predicted hull form. Cheers, Randy ----- Original Message ----- From: "David Knecht via CnC-List" <cnc-list@cnc-list.com> To: "CnC CnC discussion list" <cnc-list@cnc-list.com> Cc: "David Knecht" <davidakne...@gmail.com> Sent: Thursday, May 18, 2017 1:25:19 PM Subject: Re: Stus-List Fun Race Last Night Theoretical hull speed of a C&C 30 is 6.7 knots (based on 25’ water line). How are you hitting 7.6-8? Foils? Dave Aries 1990 C&C 34+ New London, CT On May 18, 2017, at 2:29 PM, Chuck Gilchrest via CnC-List < cnc-list@cnc-list.com > wrote: Congratulations Randy! Now enjoy the snowstorm! Chuck Gilchrest Sent from my iPhone On May 18, 2017, at 12:21 PM, RANDY via CnC-List < cnc-list@cnc-list.com > wrote: <blockquote> It was a good night for a C&C 30 MK I on Chatfield Reservoir last night - blowing 20mph. My competition was depowering, but I flew my 150 :) Grenadine did round up once on the way to the windward mark, but other than that the amount of weather helm was about right - tiller about five degrees above centerline. Managed to get a rail in the water for the first time and don't know why - I've sailed in stronger wind with the same amount of sail - must've had more rail meat those times. Anyway, Grenadine was second across the starting line. Only tacked once, and overtook the leader, before rounding the windward mark. Had the thrill of leading the fleet from there, and took line honors. Beat the next boat, a Cal 22, by 73 seconds in a 30-minute race, but he has a gift PHRF of 246 and should correct over me by a few seconds. Saw 8 knots on the knotmeter but don't trust its calibration and didn't verify with GPS. However I hit 7.6 knots on GPS last year with a fixed 2-blade prop. I think she can break 8 knots with her new folding prop; I can tell she's faster. Offseason projects paying off; wanted to share the joy. Cheers, Randy Stafford S/V Grenadine C&C 30-1 #7 Ken Caryl, CO <blockquote> _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated! </blockquote> _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated! </blockquote> _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
_______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
