What bottom coating process is Correct ?

[Guest]

I lightly sanded, cleaned and then painted my bottom with West Marine CPP. Now I have people telling me I forgot to put on an epoxy barrier coat on first. Is that necessary for lake sailing ? If so what do you recommend. I'm going to do it again if necessary since I want my boat to last ! I asked at the West Marine store and that info was not suggested so I bought what was recommended. HELP !! The boat had never been bottom painted before I bought it.

 

[Ken Shubert]

What to Look For

IF the bottom was already painted, I'd assume there was a barrier coat used and wouldn't need to be replaced. I treat my H23.5 just like you've done with a light sanding then brush on (or roll) a new coat of ablative paint. For lake sailing be sure to get a painte with the new "slime control". If you trailer and store your H23.5 out of water, be sure the paint will stand the rubbing on the bunkers and can be left out of water. These requirement may sound strange but there are paints that are formulated to be put in saltwater and left there. I won't recommend the paint I'm using because it meets neither requirement, darn it! Be sure the new paint is compatible to put over the old too.KenS/V Wouff Hong

 

[Jack]

Barrier Coat

Questions to be asked:Is the boat kept on a trailer? If so you don't need a barrier coat.How long is the boat kept in a slip and how warm is the water? If it is a 6-7 month season in water that freezes then you probably don't need a barrier coat.Does your boat have any blisters now and is it at least 5 years old and doesn't, you probably don't need a barrier coat.I am convinced from my research that blisters are a result of the layup process and the environment at the time of manufacture more than from water seeping in. That is why you can have a 20 year old boat with no blisters and a 6 month pld boat with blisters. I think manufacturers have taken more percaustions in their layups and that is why the blister cases have decreased.I have been fortunate and have had 2 Catalinas a 1977 and a 1978 neither of which have neve had a blister problem as well as a 1985 Hnter which has never had a blister problem. None of these boats have a barrier coat and have only used Bottem Kote on them. I must admit the bottoms only get painted onec every 3-4 yers since they are in fresh water.Don't worry about it. Next time you paint go ahead a nd put a barrier coat on if it makes you feel better.

 

[Wanderer138]

Good points Jack

I am in the final stages of blister repair on my 1988 H23 and based on my observations, I agree that the potential for blisters probably has more to do with the quality of the layup than anything else. The boat has been sitting in warm fresh water (the worst environment for blisters) for the last five years.Most of the hull was in fair shape, but there were some areas that were pretty bad. The blistering was not the same on both sides of the hull, so it couldn't be attributed to location or depth below the waterline.Almost all the blisters were under the gelcoat, between the first layer (chopped mat) and second (first layer of structural cloth) layer of laminate. In many cases, these two layers were visibly separated, even though there was no blister and the laminate was dry. Areas that appeared to be small blisters (about the size of a quarter on the surface) had to be ground back until I found properly bonded laminate. Some of these areas ended up being several inches square, though none went into the structural laminate.After grinding out and cleaning the blisters with acetone, I applied 1 coat of Interprotect 1000, filled the ground areas with Interlux Watertite, sanded everything fair and then applied a second coat of Interprotect 1000. I'm now about to apply 2 coats of VC Tar, followed by 2 to 3 coats of VC-17 antifouling. This should provide decent freshwater protection while still being tough enough to stand up to the rigors of trailering.PeterH23 "Raven"