In catching up with my newsgroups after a long hiatus helping burned out
folks from the San Diego Cedar Mtn fire, I would like to add to Jere's
experience with multiple coats. I have berthed my Santana 22 continuously in
the water over the past 20 years in both the SF Bay Area and the Oregon
Coast where the barnacle growth can be nasty. In both cases I followed the
advice of the previous owner to get more than one coat put on when redoing
the bottom paint. Hence, I have asked for two coats when I was in the Bay
Area and three coats since moving to Oregon. In all instances, I have gone
an average of three years between paint jobs with little or no marine growth
after pressure washing while neighbors in adjoining berths have had to haul
out every year for repainting. In a recent case I went for five years before
repainting because of pressures at work and other items taking my attention
elsewhere. The yard was prepared for a horror story when I told them of the
time since the last haulout, but to our mutual surprise, pressure washing
easily removed all growth with no damage whatsoever to the hull underneath
and the paint was still intact!

My analysis of this is that one coat can have thin spots or bare spots that
are missed in moving the support pads around. Two coats reduces this risk
and three coats reduces it further. In addition, given the cost of haul out
and the time required, the cost of the extra paint is a small portion of the
bill and worth the extra assurance. Note that I have had three different
yards do this over the years at my request with similar results in each
case. This does not mean that one can get by with poor preparation work, but
even a good preparation can be undone if the paint is thin in spots or a few
small places are missed. Two or more coats helps prevent that occurring.

Ken


"Jere Lull" wrote in message
...
Parallax wrote:

Practical Sailor just had a letter about boatyards not letting ppl do
their own bottom painting but still charging an arm and leg to have
the yard do it. My experience is that yards do a crappy job with
almost no surface preparation except for a pressure wash. The few
times I have allowed a yard to do it was a waste of money as it fouled
in less than 3 months. 6 years ago, I hauled my boat and sanded the
bottom, applied 3 coats of hard CuO based paint (BottomKote or
something like that)and suddenly had to stop sailing due to business
problems. My boat sat for 4 years being used very little in a place
that fouled heavily. Finally, I had her hauled to be brought to my
home and was amazed to find NO fouling at all. A boat next to mine
was so heavily fouled it grew oysters. I know from some past
experience that my own bottomcoating job is superior to that done by
the yardss but this was amazing. Did I do something right or just get
lucky?


From my experience, yards will use the cheapest formulation that works
in their area most years. Frankly, that makes sense.

On our first moored boat, I didn't know anything and paid the yard to do
the bottom at the start of a particularly bad year. Within a month, the
growth was almost 2" thick. They hauled, scraped and recoated the bottom
with something better at their cost.

Since, I've applied Practical Sailor's recommendations and have had
essentially no growth survive the powerwashing.

One year, as a test, I didn't overcoat our "hard" paint (supposedly it
was "dead" after 6 months' exposure to air. Little survived the
powerwashing, but there were a few carcasses of hard growth.

I few years ago, I started using an ablative paint and haven't had hard
growth survive powerwashing except where I didn't touch up the hard
paint showing through (another test). This time, I put two coats at the
waterline, a single coat below. We'll see how things worked this year,
though of course I don't know how hard our powerwash guy works.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/