Barrier Coat ?

[sailsmanship]

What do you think of putting a barrier coat on an older boat? I have an 89 Searay 30ft that recently had a survey. Surveyed good. Surveyor said that the hull is in very good condition for her age and suggested taking the anti-foul off, putting on a barrier coat, and re-applying anti-foul. I have heard that sometimes when you put a barrier coat on it can seal water in and do more damage than not having it. The boat is on Lake Erie and is in the water 5 mths. a year.

 

[EZLoader]

Re: Barrier Coat ?

Here's a link to 100's of websites regarding barrier coats on boats for you to check out. Reading just a few of these will give you all kinds of knowledge and opinions on the subject. Some do it because of blistering, waterproofing, etc.. <br /><br /> http://www.google.com/search?q=+"boat"++"barrier+coat"&hl=en&lr=&start=0&sa=N

 

[18rabbit]

Re: Barrier Coat ?

When I get the time, I’m going to read each and every one of those “100’s of websites”. <br /><br />Barrier coat is a good idea if your fiberglass boat is in the water 7-days or longer at a time. Less than that and it usually is not necessary. I am not aware of any boat paint/epoxy that suggests their product seals a vessel against water when left sitting in the water. Also keep in mind that it isn’t just water against the hull, it is water under pressure against the hull. For every 1-ft of depth there is about 1/2 psi of pressure pushing the water molecules against the micro-pores in the fiberglass. My boat has a 3-ft draft so the bottom of the hull has 1-1/2 psi of pressure trying to get the water molecules into the naturally occurring pores in the fiberglass.<br /><br />The barrier coat gets covered by bottom paint so it's not like you are going to see it. Since you will be maintaining bottom coat, you might as well go ahead and have barrier coat applied.

 

[Chris1956]

Re: Barrier Coat ?

Sandpaperman, A barrier coat is only necessary if the original hull was not made with the proper fiberglass resin. Many boats were made properly, and don't require it. I have a '88 SeaRay, and although I never had any blistering problem, I removed 10 years of bottom paint and installed a barrier coat. I then coated the barrier coat with ablative bottom paint to avoid the buildup inherent to regular bottom paint. It may be possible to ask SeaRay if your hull has had a history of blistering.<br /><br />PS - I leave my boat in the water 7+ months a year.

 

[fishingdan]

Re: Barrier Coat ?

It is not just old boats that are affected. Newer boats can have the same problem. The issue is that polyester resin (base for gelcoat and the hull) will not stop water from entering it. The newer highly controlled manufacturing processes don't create situations where the water enters and gets trapped. When water gets trapped, that is when blisters form. <br /><br />If the boat will sit in the water, always put a good epoxy based barrier coat on the hull (must be applied to a minimum thickness) and then an ablative or traditional anti-foulant bottom paint. <br /><br />Assuming you pull the boat for the winter, remove any existing anti-foulant and inspect the hull carefully. If there are any blisters, you should fix them. When the hull is good and clean, let it sit for the winter. In the spring apply the barrier coat and new bottom paint.