Bottom Coat

P

purl

Member
Joined
Jul 26, 2005
RO Number
18418
Messages
27
Looking for some advise on weather or not to apply some kind (not sure) of coating to the bottom of my 1992 26ft fibreglass cruiser.Until this season the boat was on the trailer while not in use.This season (4 months) I left it in the water(fresh) at a local marina.The water in this marina is very murky and of course the bottom of the boat is covered with a heavey layer of green algie etc.I'm planning on staying at this marina for years to come so any advice on weather or not to bottom coat and what type would be appreciated.
Thanks.
 
If you leave the boat in the water for more than a few days, it is going to get coated with local "muck".

I would recommend an ablative anti-fouling bottom paint. Like any paint job, prep work is key. The bottom needs to be scuffed up with sand paper or liquid sandpaper.

Apply at least 2 coats preferably 3. The first coat should be a color contradictory to your final color. The next coat (or 2) should be your final color. It's expensive the first time around, however, when the first coat starts to show, you only need to touch up those areas.

I prefer ablative over hard bottom paint because ablative is built to wear off constantly exposing fresh paint and therefore lessening buildup which = weight. Also, some ablatives become dormant when removed from the water (eg. drystack or trailer). I don't know of any hard paints that have that property. Hard paints to the best of my knowledge lose their antifouling properties when they are taken out of the water.

HTH
 
David gave you exactly what I would have said. Perfect advice IMO.
 
Except I would definitely scuff sand the bottom with 80 grit and not rely on Liquid Sandpaper.
 
Listen to Capt. Bill1. If he says scuff the bottom with 80 grit then scuff the bottom with 80 grit. He has a lot of experience in all things boating.
 
Another option to consider is getting a lift for your boat. This keeps it out of the water when not being used. You get the advantage of water storage without the disadvantage of the boat bottom getting fouled. Also this prevents corrosion problems from occurring. And you don't have to worry about the boat taking on water while you are away!

Here is the one I used for 7 yrs: www.airdock.com
 
Seriously, talk to other boaters at the marina and ask what type of bottom paint they are using and how well it works for them. Then go to the manufacturer's websites and study their application instructions. Also, try their paint selection guides.

Bottom painting a boat is labor intensive and involves a lot of dust and hazzardous materials. This is a project you should seriously think anout having done by an experienced pro.
 
Shouldn't boats kept in the water for long periods of time have a barrier coat applied before anti-fouling paint?
 
Barrier coating is a type of insurance against blistering. I think the OP should consider barrier coating the bottom prior to bottom painting. As others have said he needs to do some research on the best bottom paint for his area.
 
Definately do the research on your area. What I found the Mississippi is all over the board. I did mine myself this spring and when I pull out this fall it will confirm if I did it right or not. So far I have no signs of any paint peeling and the paint still looks good as far as I can see. Even though your boat may be a 1992 you will want to scrub it and STRIP it first before any sanding. I am sure that you probably have some wax on the bottom and if you just start sanding it can drive the wax in and then the paint may not stick. My process was to tape of the boat first, dont forget to leave a inch around your drives, then I scrubbed with a grill cleaning brush with a handle using soapy water and barkeepers friend. This pretty much stripped all of the scum from the previous year and started to rough it up. I then used a good stripper and wiped down the whole bottom below were I had taped off. Then I sanded with 80 grit sand paper using a orbital sander (not the best choice for the job I learned but it worked) I learned that even though a boat looks flat it is not. You need to go back and look at it from different angles to see low spots. I used 80 grit with my hand and finished scuffing all of the spots I missed and the areas the sander would not reach. I then wiped the whole thing down with acetone. Added more tape to the lines since I tend to not be real accurate with a roller. I rolled the paint on with a roller and waited one day to put another coat on. Stipped the tape off and it looked perfect. Some more items to think about. I did not thin the paint at all. Only pour a small amount in the pan at a time it drys really quick and will get thick in the pan. Do the sides quick and make one big long final pass to make sure you dont have any lines. I wasnt worried about lines on the bottom so it wasnt a big deal. It took me about 2 9 hour days to get all of the prep work done. I wasnt working real fast and 2 hours of that at least was just taping the boat. As far as personal protection goes you will need to have good chemical resistant gloves for striping, goggles or at least safety glasses, clothes you can throw out or a paper suit, a mask with filters, not just a paper mask but a real mask with something like P100 filters to keep from inhaling the dust. All together I spent about 700 dollars to paint mine with buying everything needed and then throwing out the rollers and brushes. I used Interlux Micron ultra and so far the results have been great. I do not spend any time scubbing the water line anymore and I have not lost any speed since I launched it. I did loose about 4mph since last year by adding the paint but I lost about 9 mph over the course of last year so it is a plus so far. Good luck.

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