Matt said: > I doubt Freya maintained more than 4.5 knots for any length > of time with a gear loaded kayak Matt, I'm being lazy asking you - I should really go and read up lots of SK back issues ;-) I believe the usual point where the hull's wake drag starts to overwhelm the skin drag is around 3 to 5 knots - which is why one looks for a longer kayak if one wants to spend time at higher speeds. Most tests are done with (essentially) an empty kayak - with say 20 Kg of kayak and 80 Kg of paddler and PFD. Let's say 100 KG as a nice round number. What happens when Freya adds 50 Kg of gear and water into an Epic ? Obviously, both more skin (the kayak's, of course ;-) is dragging and the hull is lying deeper and creating a bigger (taking more energy) wake. Something tells me that if you add this 50% to the displacement, you will only add perhaps 20% to the wetted area - but increase the draft and so the wake (?) - by 50%. I think these figures are about right if the hall has no flare at all on the beam or the ends - which is a gross simplification, of course. If that is even remotely true, then loading up a kayak should increase the importance of length. Let's say that you have enough in the tank to overcome the extra 20% skin drag - but you are going to run out of puff a lot sooner with the wake drag kicking in sooner (and being worse) by 50%. So you should be willing to trade more skin drag (lower down in the speed range) for less wake drag higher up in the range - the classic argument for a longer boat. Then, if (and only if) you have the horsepower of a Freya, you can really motor... Can one generalise on any increase in loading and its effect on the kayak's suitability for higher speed work ? Best Regards Paul Hayward, Auckland, New Zealand *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Mon Feb 22 2010 - 02:30:43 PST
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