BUT...was it banned because it was faster or because they weren't sure if it was or not, so to be safe, they banned it?

T.O.B. is a myth. Old, sun-baked chalky gel coat has been found to be identical in texture to Mako skin. Furthermore, by sloughing off, it acts as a lubricant and is technically illegal. This explains why old sods on old boats go so well.

Nice Try, I had a old Hobie with chalky gel coat. I couldn't win a race. Sanded it down, Awlgrip paint (sprayed) and started winning. Traded it in on a new model and won even more. I now have a H-18 that needs a "bottom Job". Hulls & sails make a big difference, right behind the "nut" on the tiller.

Rolf

You are getting into area where I wish I had the time, money and smarts to setup an exhaustive test program to find out.

I think the guys at Boeing, NASA and NASCAR have already done all the math. I don't see them doing anything with sandpaper, just lots of polish and elbow grease.

How many sailing catamarans have Boeing, NASA and the NASCAR guys buildt? <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />
Not to be rude, but there are differences. As it is, I dont know anyone besides Frank Bethwaite who has done practical tests on this. I am pretty sure there is a point of diminishing returns for going to finer and finer surfaces. But where this point is, is still pretty much an unanswered question it seems.

For what it is worth, I have sanded a boat and it seemed faster. Painted a few, and they seemed slower. I know theoretically it should be impossible to notice a difference. I also cannot prove you didn't hide speed stripes under your topcoat, but I can prove you had nominally more time-on-boat after the paint job than before .

Rolf,

Maybe you can convince the US Naval Academy Hydromechanics lab this is a worthwhile research project?

Rolf, I don't know about actually building cats but I do know there are a whole lot of NASA guys and Boeing guys racing cats here in the USA. Can any of you types tell us which is faster and why?

As for the NASCAR guys? They bring the beer... <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

How about my where I spent my college days:




Probably want to rent out the Low-turbulence Free Surface Re-circulating Water Tunnel.

One AC team (DC maybe??) did a program where they did a "grooved" finish (like a record). The idea was that the size of the groves were such that the water "saw" less surface area b/c only so many molecules could pack themselves into the space available. From an engineering standpoint, I have a hard time seeing it, but there is money in winning and therefor money in research. I would bet it had to be a surface that water was more adhesive to and therefor produced a fixed boundry layer.

Cool as a shark skin finish would be, is that maybe mother nature doing her best to produce a surface that is both durable and fast? Shark skin has to be tough but flexible, maybe smooth just didn't make sense, so that's what evolved? Note: Dolphins are fairly smooth. Maybe since they don't have thumbs they can't hold sanding blocks like we can, otherwise they might like to have a 1200grit finish <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

I like to wax regardless b/c it keeps the hulls clean. The only two rules: 1. the nut on the stick is more important than the finish of the hulls. 2. No wax where the crew stands <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

I don't recall which boat it was, but one team in the last AC had a boat with a clear carbon fiber finish. As the regatta progressed (and their results weren't spectacular) you could see the finish quickly getting duller and duller as they would wet sand at night. Personally I'm still chalking this one up (pun intended) to "wives tale" and go for a fair and clean bottom.

young america. you know, the last one to break in half. it was a few cups ago.