Date: Thu Mar 1, 2001 10:37 am
I'm a potential new owner of SWIIK113 "Astarte" but have grave concerns about blistering and moisture content of the hull below the waterline. The boat is out of the water now (at least a year or two I'm told) and is covered with blisters. Is there anyone out there in Seawind land that has had blistering problems? I suspect that since the hull was laid during the final demise of the builder there may have been some layup shortcuts resulting in the problem...any comments are welcomed..Thanks
Date: Thu Mar 1, 2001 1:16 pm
I sand blasted my hull, ground down any blisters that remained and waited (you can hurry this up if you want) until a moisture meter showed the hull to be dry. I then relaminated the ground down (with a wide circumference for fairing) spots with alternating layers of mat and rove. Painted the bottom with 2001 and bottom paint. It's been quite a while now with no reblistering.
Date: Thu Mar 1, 2001 8:52 pm
Who knows what causes blistering. I agree that while the hull is thick, the lay up of the earlier hulls might be suspect. I found 4 rather large voids between the mat and the roving on mine (K12) all on the port side. I don't know how they do the lay up, maybe one guy does one side and his apprentice the other? My boat had 2 "types" of blisters . There were about 50 nickel sized one evenly spread over the boat. Then on the keel and at the water line amidships there were thousands of pencil eraser sized blister closely packed together. As I was doing the repairs it occurred to me that these were only where it was easy to sand, which leads me to think that the second owner (I'm #4) sanded the hull each time he painted and abraded the gel coat. In fact the gelcoat on the aft end of the keel (where its real easy to sand) was paper thin.
I didn't use a moisture meter on mine, bu t instead used the West System method of taping a piece of plastic over the hull and looking for condensation. I suppose you could have someone test it with a moisture meter. If he knows what he's doing. There are actually surveyors who don't realize that the reading from a moisture meter on a fiberglass hull is not absolute only relative.
Your main concerns seem to be about structural integrity. My view, heretical thought it may be, is that blister are primarily a cosmetic problem. It's not going to sink the boat and unless the hull is delaminating probably isn't structural. That being said it will effect resale value and if your like me, it'll bug the heck out of you until its fixed.
If you are thinking about having a yard do the job, call half a dozen. I did and got wildly varying quotes. I did mine myself because I'm cheap. It's not rocket science, but taking the gelcoat off is back-breaking work. Having the hull sandblasted and then faring and barrier coating yourself might be a good compromise between thrift and the chiropractor.
I pretty much followed the procedure in the West System blister repair book. I dug out the big blisters with a laminate trimmer and carbide router bit. A countersink bit in a drill went deeper than I was conformable with.
The blisters were for the most part no deeper than the mat. With the laminate trimmer I could control the depth much better. To repair the small blisters, I ground off the gelcoat with a 7" polisher/sander using 36-60 grit paper. I also ruined the bearing of the sander, which was borrowed. Any blisters that were deeper than the mat were quite evident, so I drilled them out with the laminate trimmer. Then I washed the hull, and let it dry over winter. In the late spring I filled the holes with West System and coated the bottom with Interlux 2000/2001. That was 4 years ago and the hull is still clean--knock on fiberglass!
One, final caveat, Don't focus on the blisters so much that you miss some other major problem. I was so concerned about the blisters when I bought mine that we (including the surveyor) didn't notice that the balsa core on the side decks was saturated with water from the leaking stantions and chainplates.
My own feeling is that if the hull isn't delaminating and the blistering is the only thing wrong with it, then get the boat. However, seller really should pay part or all of the cost of having the bottom done.
Date: Thu Mar 1, 2001 9:40 pm
Our vessel was covered with nickel size blisters when first purchased. We had the gel coat sand blasted off, had two coats of epoxy 15 milsthick applied, a sealer on top of that and two coats of Trinidad. That's over 10 years ago and it's still good!!
Date: Tue Mar 6, 2001 7:21 pm
When I had my SW II hauled, I also noticed what at first thought was minor blisters but on closer inspection it was more than I had hoped for. I had anywhere from dime size to grapefruit size. Very few went into the roven mat but some did. My repair (and by no means am I an expert) method was that upon excavating to sound material I left the ouside to dry and moved to the inside for modification/refit projects. I let the outside go till the following year before I started the filling and fairing process. I had no moisture meter nor did I try covering the area with plastic to look for condensation, but the two hot arkansas summers should have dried her pretty good. I used west system epoxy with colloidal silica ashesive filler (#406) to repair the deaper ones. If you use the 406 try to remove as much as possible befor it kicks because this stuff is very hard to sand. In the areas where the depth was not to extreme (i.e. between the gelcoat and the first layer of roven mat) I used low-density fairing filler (#407). This stuff is easy to fair.
After all fairing was completed, I applied two layers of InterProtect 2000/1 and 3 coats of Pettit ACP 50. After all the work and with the boat in the water for well over a year now, all seems well. Will see.
Date: Tue Mar 6, 2001 8:59 pm
I've had my boat (88K) hauled by all the major yards in Fort Myers, FL over the years, and all have recommended "leave the blisters alone" Small blisters are not structural, and you can't see them! BTW, Solution had about fifteen quarter sized blisters when I bought her six years ago, and they have remained stable and unchanged over that time (wish I could say the same for myself).
I have never heard anyone except a fanatical racer (used to be one) come up with a legitimate reason to worry about small stable blisters.
2040 Aug 20, 2002
Dear SW II interested parties
During a routine haulout for bottom painting, I noticed the hull was not drying and showed some signs of water leakage in spots on the hull. Although there were no blisters, I used a grinder and spot ground the water leakage areas. What I found was many areas had water behind the barrier coat that was applied 15 years ago. Pettite Corporation representative was called in and I was informed that the marine repair yard had used, 15 years ago, a material designed for above water use below the water line. Therefore I had to remove all the bottom paint, all the old barrier coat. With the barrier coat removed the hull dryed quickly, which left a hair like material which is applied by chopper gun, and was almost devoid of resin. It was almost white in appearance. This hair like material had soaked up water to an astonishing degree. So you guessed it, I removed all the hair like material, about 3/16Ē thick.
Thankfully the mat exposed below it was like new, resin rich and hard as concrete. After leaving the vessel to dry, and using a moisture meter, to acceptable values, I am presently installing 3 layers of fiberglass cloth, using epoxy resin and vacuum bagging, which is a slow and tedius process but which will create a new bullet proof barrier coat, next Iíll put a new barrier coat on top of that, double protection, and then the bottom antifouling paint. Iíll keep you posted on the project. This will ensure a stronger and waterproof but very expensive hull for longer than Iíll ever be witness to.
2041 Aug 20, 2002
I have barrier coating on Tuesdayís Child. God I hope Iím OK with what was put on it. some year before I got her.
Best to you and Brenda