How long does race bottom prep last?

[paulmcquillan]

This next haulout we are planning to do more than just tip & roll the bottom paint in prep for the local PHRF club racing.

Question.... if we spend more time fairing the bottom and then smoothing with perhaps 200 grit & 400 grit, how long will that improvement last?

-- Does the regular bottom cleaing undo our work?
-- What will be required for prep again when the antifouling is reapplied at the haulout AFTER this one?

Assume bottom cleaned by diver monthly. She is a 41 ft keel boat in the water all year long in S. CA. Existing bottom paint is a hard modified epoxy; Interlux Ultra Kote
Thanks
Paul

[paulk]

How long you have Improved Performance due to wetsanding your rolled & tipped hard - modified expoxy will depend upon a number of factors. Most important is the number of crew (ten or more is best) you have working on the sanding. Having pictures of DIFFERENT crew, each performing a stage of work with subsequently finer paper over what is obviously several days will enable you to sit at the bar and send a definite message to your competition, This should work for about a month for each set of four photos. Beyond this, however, is having your crew be able to truthfully say that they spent xx hours over yy days smoothing the bottom of your boat. If you can get them to tell other sailors (especially your competition) this, it should work for about a week per each individual crew member. (Hence the need for large numbers: 10 crew = 10 weeks of improved performance.) Regular bottom cleaning after 400 or 600 grit should be done with a chamois in order to maintain the fiction that it makes that much difference.
There are so many variables in PHRF racing that the benefits of going beyond a simply smooth paint job are likely unmeasurable. Moving a jib lead four inches one way or another will probably have a bigger impact -- how often do you adjust your jibleads on an upwind leg? Having the competition THINK you''ve gone beyond what they''ve done is what counts. Just imagine if you made your crew come to a "secret sanding session" in the dark of the night, and then a couple of "clandestine" photos were "leaked" to friends of friends of certain friends... , showing the people actually there. It might be worth six seconds a mile for two months, keeping the other guys psyched out and guessing, and all you''d need would be a couple of sixpacks. You wouldn''t even need to get sandpaper, or do any sanding, so long as they think you''ve done it! You could also ask the diver for a weekly contract to show at the club bar or other appropriate setting. (The monthly contract is the one you agree to and send back to the diver -- no one else would assume to question him about how often he does your boat, would they?)

Having a smooth, clean bottom IS important, but after a while, you get to a point of diminishing ROI, as far as the time & effort are concerned. Maybe a smoother bottom would shave five seconds off the length of a race. Perhaps the sanding time time would be better spent in improving tacks and jybes, where it would be easy to save 20 or 40 seconds in a race. You decide.

[maestro]

LOL !!!!!!!!!! sO true, so true, so true

[paulmcquillan]

Actually used the large number of crew who each sanded XX hours. Then publicly attested to that work.

LOL. Happy to report that it worked at the bar AND on the course.

[Robo dapainter]

The race prep antifoul should last as long as your regular antifoul as long as sufficent antifoul was applied. The antifoul may perform better due to the exposing of the copper oxides from the sanding.

[sailingdog]

It also depends on whether the boat is stored on the hard or in the water. If it is on the hard, the sanding will probably have an effect for longer, as the chance of growth fouling the bottom is greatly reduced.

That said, I seriously doubt that fairing your boat's bottom with sandpaper is going to make much of a difference, unless it is in really lousy shape. Time spent practicing tacking and gybing is probably a far better investment.