Bottom paint prep

[K2MSmith]

Will talk to them Monday , but yard has done a lot of sanding of hull to prep for bottom paint which I wasn’t really expecting ( first time I’ve done this as the boat is new to me about 2 1/2 years ) . They showed me a few larger blisters and peeling paint they recommend for repair which I agreed . ( another 7-8 hours of work ). For these sections which are sanded it appears the fiberglass is exposed. Does this normally have to be gel coated again ? What should I be expecting. I wasn’t expecting as much prep / repair work which I guess is a good thing to do now than later .

 

[Loren Beach]

When we have repaired a few blisters, on two different boats, we faired them in with thickened epoxy. Then over-coated with bottom paint as usual. Note that blisters that go into the laminate will need to have some cloth or bi-ax layer into them. There are good sources for learning about this, like the information and illustrations from the West System folks.

 

[K2MSmith]

When we have repaired a few blisters, on two different boats, we faired them in with thickened epoxy. Then over-coated with bottom paint as usual. Note that blisters that go into the laminate will need to have some cloth or bi-ax layer into them. There are good sources for learning about this, like the information and illustrations from the West System folks.

I’ll actually worried more about the sanding through the gel coat in some areas like the bow. I’m going to ask them what they plan on doing with these patches Monday . I’m guessing they have to epoxy over it .

 

[Frank Langer]

If all the bottom paint has been, or will be removed, you could consider adding several coats of Interprotect 2000, which is a barrier coat of epoxy paint, intended to prevent future blisters. But it can only be applied if bottom paint is gone and hull is dry. It's expensive, but maybe worth it if the boat is in good shape and you plan to keep it a while.
Frank

 

[K2MSmith]

I would be interested in doing that in a future haul out , but I’m also replacing the rod rigging ( the 33RH has complex rig ) at the same time and need some additional issues addressed so it doesn’t work with the budget, but good to know for the future .

 

[Pete the Cat]

I would not be worried about sanding off the gelcoat below the water line. Some premium boats like Swan used to leave the hull below the water line bare (though they had epoxy hulls, not vinyester, but I doubt that makes a difference). In my experience, gelcoat below the waterline is a principle contributor to many cases of blistering, it does little or nothing to protect the substrate laminate from water intrusion despite some folks' imaginations. I would also caution you against slapping coats of barrier coating over any gelcoat that has not been in a dry state for some time. I spent $14K fixing one of my boats because a well known boat yard put a barrier coat over a moist hull and thousands of small blisters were the result. I probably should have ignored them as they had not penetrated any of the resin, but I was new to the boatyard business at the time. I eventually removed all the gelcoat and epoxied the entire hull of that boat and I am still sailing it 32 years later with no new blisters. My guess is that barrier coats have been responsible for as many blisters as they have presented, but they are a business for the boatyards. And kudos to your yard for sanding prior to paining--they must be reputable. The East Coast yards generally slap another coat with nothing more than pressure washing and the older hulls here eventually resemble the surface of the moon and will require some sort of blasting someday to remove the thick crud. They simply do not have time in the busy launch and store season to do things properly. My opinion is that you have nothing to worry about and seem to have a good yard working on your boat. FWIW. Just one opinion.

 

[Christian Williams]

. For these sections which are sanded it appears the fiberglass is exposed. Does this normally have to be gel coated again?

I don't think so, for the usual blister fix. Anybody disagree?

[posted simultaneousy with Ray]

 

[K2MSmith]

I would not be worried about sanding off the gelcoat below the water line. Some premium boats like Swan used to leave the hull below the water line bare (though they had epoxy hulls, not vinyester, but I doubt that makes a difference). In my experience, gelcoat below the waterline is a principle contributor to many cases of blistering, it does little or nothing to protect the substrate laminate from water intrusion despite some folks' imaginations. I would also caution you against slapping coats of barrier coating over any gelcoat that has not been in a dry state for some time. I spent $14K fixing one of my boats because a well known boat yard put a barrier coat over a moist hull and thousands of small blisters were the result. I probably should have ignored them as they had not penetrated any of the resin, but I was new to the boatyard business at the time. I eventually removed all the gelcoat and epoxied the entire hull of that boat and I am still sailing it 32 years later with no new blisters. My guess is that barrier coats have been responsible for as many blisters as they have presented, but they are a business for the boatyards. And kudos to your yard for sanding prior to paining--they must be reputable. The East Coast yards generally slap another coat with nothing more than pressure washing and the older hulls here eventually resemble the surface of the moon and will require some sort of blasting someday to remove the thick crud. They simply do not have time in the busy launch and store season to do things properly. My opinion is that you have nothing to worry about and seem to have a good yard working on your boat. FWIW. Just one opinion.

The boat yard doing the bottom is Spaulding. They also operate a boat works school and in fact they had a class observing my boat when it was hauled . So far good experience and nice people. The rigging ( happening at the same time ) is south beach riggers . They are also very knowledgeable and have a full machine shop that can manufacture almost anything they can’t buy , They are making new mast sheaves for me , as an example while doing the rigging . Much easier to do when mast is off .

 

[nquigley]

. For these sections which are sanded it appears the fiberglass is exposed. Does this normally have to be gel coated again?

I don't think so, for the usual blister fix. Anybody disagree?

[posted simultaneousy with Ray]

Agreed - don't replace the sanded-off gel coat. My first boat (Beneteau 235) came into my life with lots of good-sized blisters. After doing the proper removal and repair, I had a patchwork quilt, so I put 2 coats of interprotect 2000 on the hull before bottom paint - never had another blister.

 

[K2MSmith]

I’m headed to the yard today to see progress. I’ll post some pictures. It looks like they’ve sanded most of the previous paint layer off . After some minor blister repairs and removing peeling paint , they are going to start painting. The estimate for the work including the crane and paint is about 3K . ( E33 ) . Not cheap but they are not just painting either.