GF12-14-15 Question About Paint Cracking

[alegath]

I now have about 24 hours on my GF-14. I took it out into the Gulf of Mexico around Cedar Key FL last week. (1st time in salt water). The water did not appear to be too rough, maybe 1ft swells, but there was some pounding & a LOT of spray. When I was washing down the boat I found a lot of longitudinal cracks in the paint. All the cracks were between the spray rails & rub rails along the center 1/3 of the sides, and most appear to be about 1 to 1.5" long. Most were on the starboard side, but there are also a few on the port side. The paint is Imron which I have found to be very tough & flexible in the past. Has anyone else had this problem? Any ideas as to what may have caused it?
Thanks,
Alan

[JeffS]

What type of plywood did you use for the boat? Pine or Fir can cause checking, not sure that is you problem.

Jeff

[cottontop]

I have them too in my OD 18. They occured after my first trip into some choppy salt water. I know the water didn't do this, but until reading this I had forgotten about checking. I got a little short on "marine ply" at the very end and just used some exterior pine I had. The cracks I have are right on some edges of the front and back boxes. I should have covered these in cloth but didn't. I have all the supplies I need to make the repairs: just not the time right now. One of my co-workers from another office retired on very short notice. I'm doing my job and his until they hire someone. I tell my boss he has a 2 for 1. I'm doing the job of 2 people for the wages of one. Good luck with your repairs. Cottontop

[MadRus]

That's a nice boat, sorry to hear about the problem. I just wanted to add that painting over uncured epoxy might cause this kind of cracking. Learned that one the hard way. And if you use straight paint without priming, sometimes you can get bad adhesion.

[jacquesmm]

It's not structural, probably cheap plywood checking.
Even the best paint like Imron can't help.
Solution: if you care about the looks, start with marine plywood like Meranti or Okoume.
Meranti marine 6566 cost less than marine fir around here.
If you use fir marine or exterior, fiberglass the surface with a light fabric like 4 oz. This will cost more than to start with Meranti and that is why we call exterior or marine fir a false economy.
At this point, there isn't much you can do, sorry.

[Cracker Larry]

Allen, no advice on your paint problem, but I would like to see some more pictures of that GF set up. Very interesting. Do you have a gallery or a link to a pic site? If not, could you email me a few shots from different angles? Thanks!

[smilinmatt]

I built mine with BCX and it's checking quite a bit. But mine's also four years old and my 18 month old motor has 137 hours on the hourmeter - so it sees some use. I'm sure it's nothing structural to worry about. This summer, I got caught up in a front at Homossassa (unfortunately I put in at Crystal River). I spent two hours going the 10 miles into a 25 knot wind with a 2' to 3' chop. If there was anything to knock loose, that ride would have done it.

[alegath]

I used marine fir, and a primer filler over epoxy that had cured for at least a week. I take it this means I will have to sand it back down to the epoxy & lay a thin glass cloth over the boat before re-painting it? I am more worried about water being able to get to the wood, if I knew it wouldn't happen again I would just put some clearcoat over the existing paint. Here is a link to more pics : http://photobucket.com/albums/v219/alegath/GF-14/
Thanks for the help!

[Tommy D]

Someone told me canvas airplanes are painted with epoxy that has less than recommended hardener put in it so that it remains more flexible. Havent tried it ....wondered if anyone else had heard of this?

[Cracker Larry]

Tommy, sorry, you were told wrong. Not saying someone hasn't tried it, just saying it is a BAD idea. You should never vary the hardener ratio to achieve flexability.

No airplanes use canvas nowadays. There are many better, cheaper, lighter solutions. There are coatings made for aircraft fabrics specifically. Even for the old canvas coverings.