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Another bottom paint question!

Feb 19, 2008
200
Catalina Capri 18 ann arbor
Hi everyone,

Ive read many threads about bottom painting, i my be over thinking this, but I want to do it right.

The clerk at West Marine suggested Pettit Hydrocoat, because I have a previously painted bottom, but I don’t know what the pervious owner used. She said Hydrocoat can be applied over all bottom paints as long as you clean them up - remove loose flaky , sand smooth, etc.

just for reference, I‘ve exclusively sailed it off the trailer in the three years I’ve owned it, I need bottom paint this year because I‘m going to keep it in a slip in Lake St. Clair. The previous owner said he painted the bottom for the one season he sailed in salt water, but mostly he trailer sailed as well.

My concern is there seems to be different instructions on the can than on the website.

The can says “traditional soft anti fouling paints need to be removed completely.” The website says paint over any “hard or ablative antifouling paint.”

next one is wiping it down. The can says wipe down with a damp rag to remove sanding residue. The web site says wipe with a specific product (Pettit #120 thinner - or some such).

I’m fortunate to have many friends who are engineers, yesterday we spent a good hunk of the day getting the boat off the trailer bunks in a way they assure me is safe (still scares the crap out of me). I’d like to get this done quickly to get it back safely on its bunks.

any advice?

john
 
Feb 19, 2008
200
Catalina Capri 18 ann arbor
I may have posted that too soon. I think my confusion is that some of the Qand A on the site is user generated, if I read the technical sheets they are the same.

I guess removing all the old paint is the best plan......gonna start sanding.
 
Oct 26, 2010
1,376
Hunter 40.5 Beaufort, SC
I may have posted that too soon. I think my confusion is that some of the Qand A on the site is user generated, if I read the technical sheets they are the same.

I guess removing all the old paint is the best plan......gonna start sanding.
You will probably want to do some "light sanding" for hard paint to assure good paint adhesion. However, before I started the process of sanding "all" the previous bottom paint down to the gel coat I'd attempt to determine if its a hard paint or an ablative.

If its a good quality hard paint that has only one or two coats (PO said painted it once and there is no evidence of excessive buildup) then painting over it per the manufacturers instructions is probably the best choice. I'd take a white T-shirt and rub the paint with it. If some of the paint shows up on the rag it is most probably an ablative paint. The last ablative I used would even leave a "powder reside" if you rubbed it with your hand when it was out of the water. If there is no evidence of the paint coming off on the rag it is most likely a hard paint or one of the "harder ablatives." There is a range of how "hard" the ablatives are depending on the formulation. In my experience (limited as it is) true hard paint leaves no residue on the rag. I recall I even once used a "scrubby pad" on the hard paint and nothing came off on the pad.

I note your post says the manufacturer says "traditional soft antifouling paint" needs to be removed? Does the PO know what specific paint he used? I guess a Capri 18 might not be too hard to sand down but if it were my boat I'd really try to determine if it is hard paint before I took it down to the gel coat.
 
Feb 19, 2008
200
Catalina Capri 18 ann arbor
I know it’s ablative paint because, as you said, for three years now even dry if you rub the bottom you get blue fingers. We sometimes soil shirts pretty bad when we launch it - but I’m surprised how easily it washes out.

it seems to come off pretty easily with some light sanding and a power washer..... shouldn’t take too long.

next time I sleep aboard I’ll probably wish it was a 27 footer, but today the size suits me fine!
 
Feb 19, 2008
200
Catalina Capri 18 ann arbor
I take that back, this is not coming off easily,
that RO sander gets heavy upside down at arms length!

I will survive this day!
 
Jun 17, 2017
22
Catalina Catalina 22 Pensacola, FL
I feel for you. In February of 2018, I still had my Capri 18 and the bottom was painted with some type of black paint that looked pretty ugly. I power washed it and a lot of the paint came off with power washing. I removed what I could with paint remover and then started with my sander. What a mess. I will never try that again. But I did get it down to the Gel coat. I added three coats of sealer and then finished with two coats of Pettit Vivid. Looked great, and then I sold the boat last fall. I didn't take the boat completely off the trailer. I did the work in sections, using a floor jack, a 55 gallon drum and 2 x 6's to create bunks to lift one side, do the work and then the other. Took a long time but the process worked. Be sure and wear a respirator as there will be lots of dust of unknown quality. A sander with a connection to a shop-vac will help some.
 

Joe

.
Jun 1, 2004
7,389
Catalina 27 Mission Bay, San Diego
You can simply follow directions for existing painted surface. Most trailered sailboats will have an ablative style anti fouling paint that is unaffected by air and sun. It is not necessary to remove old paint unless it's flaking or thickly built up.

If there are bare gel coat spots on bottom, you will need to follow instructions for that condition. Normally this means an epoxy primer that improves adhesion between the gel coat and new bottom paint.

Don't over think this basic maintenance activity. Clean biologicals from the bottom by power washing and wiping down with recommended solvents. Lightly sand to improve new paint adhesion. Apply paint with disposable 3/8 inch rollers and chip brushes. Putting additional coats on high wear areas, such as leading edges of keel and rudder, is recommended.
 
Feb 19, 2008
200
Catalina Capri 18 ann arbor
It was an adventure, but it got done.
My system for lifting it off the bunks sort of failed in slow motion (So much preferred to the option of a catastrophic failure while my head was under there!). The worst outcome was that it landed considerably off center, about half of the vertical portion of the keel was on the support. If it was any further off center I’d have been nervous about trailering it.

as is, tomorrow I’m towing it 5 miles to a ramp, where I can float it off the trailer just long enough to re-center it.