Assuming I take the basic dimensions (17'8" x 21'8") and shape of a CD Caribou (maybe take the rocker out of the tail) and reduce the beam to 19", what increase could be expected at 5 mph cruise speed? I know I've seen formulae on the list, but I neglected to save them. Thanks. *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
In a message dated 7/28/00 8:06:36 PM, sullivaned_at_pop.mts.kpnw.org writes: << Assuming I take the basic dimensions (17'8" x 21'8") and shape of a CD Caribou (maybe take the rocker out of the tail) and reduce the beam to 19", what increase could be expected at 5 mph cruise speed? I know I've seen formulae on the list, but I neglected to save them. >> I'm pretty sure that there would not be any (speed) increase at 5 mph. 5mph on a surf ski and 5 mph on a barge is still just 5 mph. Maybe the force needed to drive the boat at that speed will decrease as the beam decreases. ;-) Sorry, I couldn't pass this one up. Don't even get me started on what you've listed for the basic dimensions of a Caribou. Even Melissa would paddle a different boat if the Caribou were 21' 8" wide. Good luck with you question though! Ballast Boy (the seakayaker formerly known as Speed Bump) *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
LedJube_at_aol.com writes: > <snip> > you've listed for the basic dimensions of a Caribou. Even Melissa would > paddle a different boat if the Caribou were 21' 8" wide. But think of the stability! You'd probably have to go for a non-standard paddle though. ---------------------------------------------------------------------- snark_at_tulgey.org aka Glen Acord http://www.tulgey.org/~snark if ($snark eq "boojum") {vanish("softly","suddenly")} *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
E. Sullivan asked: >>Assuming I take the basic dimensions (17'8" x 21'8") and shape of a CD Caribou (maybe take the rocker out of the tail) and reduce the beam to 19", what increase could be expected at 5 mph cruise speed? I know I've seen formulae on the list, but I neglected to save them.<< I calculate that reducing the waterline width by 2" reduces the Caribou's 250 pound (plus kayak weight) wetted surface from about 21.05 to 20.24. Plugging this change and a 2" narrower beam and finer entry angle into the spreadsheet (that you can download at the Mariner Kayaks website in "downloads"). I get that the drag at 5 knots (about 5.75 mph) will be about 2.7% less. At 4.5 knots (less than 5.2 mph) about 3.1% less drag. At 4 knots (~4.6 mph) about 3.3% less drag. I didn't take into account the increase in wetted surface the additional stern keel might add since in real life the additional tracking stiffness might more than offset the extra wetted surface for a kayak where strokes alternate on each side. This change will probably cut the stability of the hull at least in half, so unless you are designing a race kayak you are giving up a lot of stability for a small improvement in drag. If you are designing a race kayak, you could do a lot better than to start with a Caribou. Matt Broze http://www.marinerkayaks.com *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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