Prep and proceedure for bottom paint

[Numbknots]

Say guys,

I am told there is no dumb question asked. I am planning to pull the Tolly some time in about Oct/November and plan on installing a new Transducer, checking struts, bearings and doing a close inspection of the bottom/ blisters etc. and then repainting.

I have never repainted a Fibreglass boat. from the looks of it during survey and during the two times I have dove it to replace zincs the bottom paint looks to be in good shape accept for a few areas around the boot stripe.

It looks as though there may be several coats of paint over a "barrier coat" (some over a few barnacles).


What is the best way to remove or prepare the bottom for repaint and recomendations on the best paint???

Thanks,

Tim

[heymagic]

You could probably just scuff it up and add another coat . Use an ablative paint, I like Petit Trinidad with slimeacide. Lot's of plant growth in South Sound and not much water movement. Barnacles are bad in the late spring.

[bradvo]

Is it still as important today as it was some years ago to know that bottom paints are going to be compatible with each other, if you change paints? Since we also have never bottom painted our new used boat I do not know which brand was on there and we will need to re paint this spring. When we had her out early last spring the paint did not look that bad buit i must have around a foot of slime green grass growing off around the boot stripe- it was scrubbed off 3 months ago and diver is due back in a week or two.
Brad

[heymagic]

There are some compatability issues but generally power boats in Puget Sound have an ablative paint, probably Interlux Bottomcoat. The harder vinyl based paints don't like going over normal paint. In 20 years of bottom painting and a bunch of boats I've not had a problem yet....Ideally a boat would have a barrier coat, a coat of a different colored paint and then 2 coats of the final color. The undercoat starts to show through then it's time to repaint. Usually you can just clean the bottom, if it has a bunch of layers of the hard stuff then scrape and sand them off. Try to remove as much as possible with the pressure washer, if that knocks it off it wasn't stuck very good anyway. Most times you can get 2 or 3 years with a good paint job. Too much old paint adds weight and causes a rough water flow over the hull.

[Numbknots]

Gene,

When I hauled the boat for pre-purchase survey there was 4-5 chips off the bottom that showed a "grey" paint underneath. I was told by the surveyor that the (gray) was a "barrier coat". I do have the paint type in the "records" so I should be able to find compatability and or use the same paint?

I was told that using "soda" blast was a good way to remove the old paint if a person wants to make a clean new bottom? I have a good pressure washer capable of 4k pressure.

I have now dove the boat twice and for sure it is easier to remove any buildup when it is wet. I noticed while diving that there was a "cloud" of blue coming off as I rubbed the bottom with a softscrub. (I was told that that was normal and how the bottom paint was supposed to work?)

It has been close to two years since it was painted? It appears that the "boatyard boys" pretty much just P/W and painted over what ever was there? ( I could see that there were some barnacles on the strainers, rudder, struts and fittings.

Brad, we could get together and I could dive your boat for you, perhaps if you are able to come down here or when I am up that way we could do both boats at the same time (My experience is the commercial divers do the job pretty reasonably for $$, challenge is it is hard to tell the kind of job they do, especially if you are not able to 'see the work'

Tim

[bradvo]

Thanks for the offer Tim but I have a guy that I have been using for years and has been doing me right. I am on a maintenance schedule with him and have stayed the course since he is on time for the dives and has been able to help me out in years past with emergency dives as well.

I do have a question for you, what size zincs are you using on your trim tabs and have you ever used those big hockey puck size ones?
Brad

[heymagic]

The blue cloud indicates normal ablative paint. If 2 years old it's about due. Soda blasting is good for fiberglas, problem is with a boat that size to have a yard do a crappy job of painting at todays prices. OTOH that'a a lotta boat to paint yourself!! Good divers are hard to find. Had a friend that had his OD intake plug from barnacles, burned up impellor and exhaust hoses, ruined his vacation that year. Boat had been "cleaned" regularly by a diver...definitely keep the guy you have !

[Numbknots]

Brad,

By all means if you have a good diver, keep em. Just don't hesitate to call if you need a hand? Same goes for other IBNW guys.

Tim

[bradvo]

Tim, about my trim tab zinc question, have you tried the hockey puck size ones?
Brad

[Numbknots]

Brad,

I have not. My tabs have small rectangular zincs, and are bonded through the hull bolts to the main bonding buss. Shouldn't be a problem mounting the hockey puck zincs though?

Tim