Philip wrote:Sanding the bottom? What kind of bottom paint are you using? Does the boat stay mostly in the water?
I am thinking of reapplying bottom paint to my trailer-sailer in the fall, but it has some ablative paint that I do not plan to sand much. It lives on a trailer most of the time, so I hear hard bottom paint would lose its effectiveness (eficacy? efficiency?) when exposed to air for long periods. I was thinking of TotalBoat Spartan (multi-season ablative, lots of copper content, good reviews). Others I have read good things about are Interlux Micron CSC (more expensive), Interlux Bottomkote NT (not multi-season), and Petit Horizons.
The prior owner did a horrible job of prep work for his bottom paint over the 8 or so years they owned it, looked like they hardly sanded, and he didn't understand how to maintain "barrier paint"...combined with the yearly or every two years..application of ablative.
If you've seen pics of our boat in prior years when she's up on the stands...the bottom had patches where gelcoat was exposed, and you could see many patch layers of barrier and ablative.
Barrier coat goes on in several coats...just on the gelcoat. Should last a good 10 years.
And ablative paint gets put on annually or every two years or so (depending on use)...on top of the barrier. Each season when hauling in the fall, a good power wash off...until you just see the barrier paint (you can tell the difference)..and slap on ablative in the spring again.
Yes some ablative can lose efficiency if exposed to the air. There are some meant for salt water only, and some for fresh water.
For "trailered boats"...you're not in the water all the time. Really don't need ablative. Many wouldn't even want barrier. But there are "hard" seasonal paints. Interlux is a good brand, also Petit....you got a few versions of Petit Hyrdo coat, and their "harder" paints ...which you might want to check out, like Trinidad. If you're trailering, you likely don't need (or want) the soft fast release ablatives.
We keep ours in a fresh water river...the Connecticut River. Many only paint "the smile" of the boat (around the water line, and front lower portion of the bow that shows)....and leave the bottom naked. Fast moving current (6-8 knots)....nothing grows much, just slow tea colored scum line. With a decent paint job can go 2-3 years without repainting. However if I kept it out in Fishers Island Sound...fresh water, would need fast ablative paint every year.
So to fix the prior owners horrible bottom paint maintenance, the bottom looks like an alligators back (ok..exaggeration..but..)...I wanted to have her sand-wet blasted..all the way down to the gelcoat, and I was going to do 4-6 coats of barrier and then a coast of semi hard Petit ablative. BUT..with the market crash, and real estate slow, we're living off of 1x income (me)..so that wasn't in the cards for this summers budget (a good 2500-3000 just to blast her...plus many gallons of very expensive paint). So I did a sand job and hand brushed barrier on the naked spots and put on a heavy coast of cheap ablative just for this season and we'll target the big overhaul next year.
From what I know, hard paints are the ones that lose effectiveness when exposed to air for long periods, ablative is better because top layer gets renewed, and the ease of reapplying. Mine lives on a trailer usually, but I am about to put her in a marina for a month at least. A friend of mine left his for 3 weeks in the water naked with only gel coat and you couldn't see the bottom from barnacles at the end of the month, looked scary.
