[Rhodes22-list] Re: CB trunk, bottom paint

[Roger Pihlaja]

Richard,

High CuO content bottom paints with a hard epoxy binder function by slowly
leaching the copper to the surface.  Since the CuO is already in an oxidized
state and the epoxy binder is inert to oxygen at room temperature, air
exposure should have no effect upon these properties.  Pettit Trinidad was
developed for use in extreme fouling tropical conditions, i.e. like the
Caribbean Sea where the island of Trinidad is located.  Since sea water does
not have a very high cuprous ion content, there should be no suppression of
the biocide solubility.  I don't think Lou should use one of the ablative or
sloughing bottom paints inside his centerboard trunk because of the close
clearances and potential for mechanical and abrasive wear.  I suggested
Petit Trinidad because it dries to a very hard slippery finish and should
last as long as anything else currently on the market.  Naturally, you would
also want to coat the centerboard with bottom paint & I would think Pettit
Trinidad would be a good choice here as well.  With so much CuO around on
both the centerboard trunk & the centerboard, I don't think marine growth
will have much of a chance to get started.  But, your point regarding
raising & lowering the centerboard a couple of times per week is well taken
& would be cheap insurance.

Roger Pihlaja
S/V Dynamic Equilibrium

----- Original Message -----
From: "Richard Smith" <sailnut at worldnet.att.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Wednesday, December 01, 2004 3:11 PM
Subject: Re: [Rhodes22-list] Re: CB trunk, bottom paint


> < The high CuO
> > >content should keep the fouling at bay for years inside a centerboard
> trunk.>
>
> I don't think this will work in salt water!  Once exposed to the air these
> seasonal coatings lose much or all of their antifouling properties.  It's
> possible to revive them (slightly) by sanding.  Difficult to sand the
> interior of the trunk though.
>
> The issue of centerboard trunk fouling (in boats always in the water) has

> never been successfully addressed.  I think the best approach is to paint
> the board itself with a quality antifouling compound and lower and raise
it
> a couple of times every week.  This will go along ways towards eliminating
> marine fouling in the trunk.  By following this schedule my boat had
always
> had very little hard growth  in this area.
>
> Richard Smith
>
>
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