2nd comment and clarification: If I was racing regularly with regular crew, and had decent sails and was finishing consistently above midfleet, I'd invest the money, paint a thrid coat, and spend the time and burnish the bottom. A smooth bottom makes all your expensive sails faster. Checkout the bottoms of the consistently winning sailboats in the boatyard. Chuck S
> On 04/03/2025 11:08 PM EDT CHARLES SCHEAFFER via CnC-List > <cnc-list@cnc-list.com> wrote: > > > Interesting thread as I plan to switch bottom paint to Black Widow this > spring and considered the burnishing option. > > I am convinced burnishing makes the hull faster, but not worth the extra > money and labor for my situation. > > I decided to not paint a third coat and save the money for paint and hours of > labor burnishing, also. I'll paint two coats and get them as smooth as > possible and call it a day. Paint is expensive and it's not good for the > environment to sand it off. I'm convinced a burnished hull is faster in > light winds, as it offers less resistance. This is less of a factor in good > wind. And in strong win, if you are well powered up, you should be making > hullspeed, and that's all you can do anyway. > > To test this theory, I can imagine painting a smaller vessel, say a kayak, > and set it in a river with person in it, and a simple fish scale tied between > the bow and a tree, and measure the resistance, "paint unburnished" vs "paint > burnished". > > That's my two cents. > Chuck Scheaffer, Resolute 1989 C&C 34R, Annapolis > > > > > On 04/03/2025 10:41 PM EDT Marek Dziedzic via CnC-List > > <cnc-list@cnc-list.com> wrote: > > > > > > > > It is more than just articles. There are a lot of actual lab tests. I would > > gladly participate in your bike test. I use 28 mm with 80 psi. Btw. I > > switched from 22 mm at 110 psi, and I am faster (Strava supports that > > claim). And I am a clone of myself (if anything, I should be slower as I > > moved to the next age category). > > > > > > > > Marek > > > > 1994 C270 Legato > > > > Ottawa > > > > (should I include the bike model?) > > > > > > > > From: David Knecht via CnC-List <cnc-list@cnc-list.com> > > Sent: Thursday, April 3, 2025 5:58 PM > > To: CnC CnC discussion list <cnc-list@cnc-list.com> > > Cc: David Knecht <davidakne...@gmail.com> > > Subject: Stus-List Re: Sanding/burnishing hard bottom paint > > > > > > > > Unlike boat bottom smoothness, there are lots of articles out there on tire > > pressure and speed (with data). I would take you up on your race offer, > > but to do it right, we need to clone one of us and put one clone on your > > bike (21 mm tires at 120 psi) and one clone on my bike (28-32 mm tires at > > 80 psi). Dave > > > > > > > > Myths Debunked: Higher Tire Pressure is NOT Faster > > https://www.renehersecycles.com/myth-16-higher-tire-pressure-is-faster/?srsltid=AfmBOork2tEEWJzCXYhjHdtya_q1DZZEJfm5CdFQ4lk7ST0UVoCYRU6r > > > > renehersecycles.com > > https://www.renehersecycles.com/myth-16-higher-tire-pressure-is-faster/?srsltid=AfmBOork2tEEWJzCXYhjHdtya_q1DZZEJfm5CdFQ4lk7ST0UVoCYRU6r > > > > https://www.renehersecycles.com/myth-16-higher-tire-pressure-is-faster/?srsltid=AfmBOork2tEEWJzCXYhjHdtya_q1DZZEJfm5CdFQ4lk7ST0UVoCYRU6r > > > > > > > > David Knecht > > > > Emeritus Rear Commodore/Thames Yacht Club > > > > Emeritus Professor/University of Connecticut > > > > Basketball Capital of the World > > > > > > > > > > > > > > > > > > > > Your contributions help pay the fees associated with this list and help to > > keep it active. Please help by making a small contribution using PayPal at: > > https://www.paypal.com/paypalme/stumurray All contributions are greatly > > appreciated. > > > Your contributions help pay the fees associated with this list and help to > keep it active. Please help by making a small contribution using PayPal at: > https://www.paypal.com/paypalme/stumurray All contributions are greatly > appreciated. >
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