Hull Blistering

[Langg]

Does anyone know if the Macgregors have problems with blistering
if left in fesh water? i know the algae and slime would be a problem,
but i read an article where some boat manufactures are more prone
to blistering than others. I think it has something to do woth the quality
of epoxy they use??
I had a boat guy trying to sell me on a bottom paint job to prevent
blistering it was quite expensive.

I will be leaving mine in the water most of the year.
He said that is what causes blistering.

TIA

[tangentair]

a search for hull blisters brought up the following http://macgregorsailors.com/phpBB/viewt ... l+blisters which you might find interesting as well as a number of others. Leaving it in the water does not cause blistering, water getting under the gel coat and into the resin does. Polyester Resin is used in the manufacturing process and is water perminable over time, epoxy resin is used for patching and painting but not for general manufacturing is not water perminable. Has something to do with primary and secondary bond strengths and curing. A good epoxy paint may help.

[LOUIS B HOLUB]

I know of one case only with a 2000 Mac X. It was in and out of fresh water, and then 1 year in a salt water slip. Apparently the original bottom paint was done poorly.

The repair was successful, however, it was a big job. The owner is a Marina neighbor of mine, and the boat looks great.

I definately would recommend bottom paint, and properly preparing the fiberglass, sanding, cleaning, and "dewaxing". I did the bottom paint on my 1999-X, and its not all that difficult.

Note: My 1999 X was done (so called) "professionally" previously, and the paint peeled, and apparently it wasnt "dewaxed". I had to remove all the paint, and completely redo the paint job. Since the paint peeled off easily, the job went easily.

[cuisto]

Keep mine in fresh water for 6-7 months of the year and developed blisters. saded them out, cleaned them up, filled them, sanded again, then 3 coats of 2 part epoxy bottom paint (interprotect 2000) then antifouling on that.

[bubba]

Our M came with bottom paint and had been kept in a marina on salt water for less than a year. It was easily preasure washed cleaned and no blistering.

[Jeff]

I notice by your signature that you are in Nashville, so my info might be relevant. I'm on Watts Bar Lake in East Tennessee. I bought my boat in Feb 2006 and I have kept it fresh water slipped here since July of 2006. Once or twice a year I pull the boat out and thoroughly clean the bottom and then apply Starbrite anti-growth marine wax to the hull. The second time I hauled it out late in 2007 I noticed a couple of dime and nickel size blisters on the hull bottom near the transom. I kept the boat out about two months and then sanded them out and reapplied two coats of wax and put it back in the water. This June I pulled the boat out for the Beer Cruise and noticed three more blisters in the same general area. I am repairing them the same way and will once again just wax. My conclusion is that for some reason the back end of the hull is more prone to blisters, perhaps because that part of the hull is very near the surface of the water where perhaps the temperature is warmer. This is just a theory, but it matches what happened to a Laser2 that I used to own and moored one summer. The Laser2 literally sits on top of the water and even though I had waxed the hull I developed orange peeling and small blisters similar to what I'm seeing on the Mac where the hull is closer to the surface of the water. I was lucky the blisters on the Mac did not go all the way to the fiberglass and sanding them down worked. (there was still gelcoat) I intend to again just repair these new blisters rewax and check it again next spring. In the spring, if I find more blisters then I will probably bite the bullet and go ahead and bottom paint. Bottom line, if you want to go without bottom paint I would apply two or three coats of good marine wax to the hull bottom paying particular attention to the area at the aft of the boat and monitor closely.

I know this is a long reply but hopefully it helps you out.