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View Full Version : Need help:supporting de-trailered boat and blister repairs.



cobra
10-17-2007, 01:09 PM
I'm considering de-trailering my boat for some repairs to both boat & trailer -'90 GT 230- and need some advice. I often see boats in yards sitting on a 3 point support; one at each aft corner and one under the V about 3/4 length forward. Is this adequate safe support for the hull or should I construct something more sophisticated? It'll probably be off the trailer 1-3 months depending on my time to finish the projects.
I have blisters all over the hull bottom. They're cracked open, kinda like a little smily face crack on the bubble, but the gel is otherwise intact. The boat used to live in the water, now it's a trailer boat and generally gets day trips with an occasional weekend soak-mostly in salt. Do I need to be concerned about repairing this or just ignore it? If it needs to be repaired, what's the easiest/cheepest rout to take?

mike o
10-17-2007, 02:01 PM
Hi, you have a case of osmotic blistering. you can google it and get the reason, Its of a chemical nature, and the problem was figured out by the chemists that make gelcoat + resin. Basically the chemical reaction that makes gels+ resins react (cross linking), reverses itself. Boats made with vinly ester resins are much more chemical rezistant, and the high quality hulls are made completly with vinlyester, or a skin coat layer right behind the gelcoat. .. To do it right, It all has to be grinded off below the h2o line with a gelcoat grinder... a miserable job. then re- gelcoated with a barrier coat of vinylester over the bare glass 1st ....... $$$$$, good luck.. Michael

MOP
10-17-2007, 02:19 PM
For the short period you are speaking of 3 points will be fine, a suggestion get someone to water/sand blast the bottom. Get references to make sure they know how to do it properly, there are far more then you can see they must all be opened up. You can add micro balloons to the first couple of layers get it fair then re-gel, that will save a lot of grunt work. Several of us up here have done more then their fair share of blister jobs, I see that it more then likely was a salt water boat. Once stripped it must be washed with fresh water until you are sure the salt has been removed from the laminate, if not done it the job will not hold up very long.

Phil

Morgan's Cloud
10-18-2007, 09:54 AM
Not to trample over Phil here , but we do this all the time out here as the only two times of the year a boat sees a trailer is on it's way to the water at the start of the season and on it's way home at the end.
I am VERY against the system you mentioned (3 point) as the rear two jack stands unless positioned perfectly under the stringers will cause deformations in the hull bottom. (Think of an improperly bunked boat on a trailer for a long period of time)

What most of us do out here is to have the boat's keel supported on two 8' long 4x4's (or larger). They are resting on a stack created by a suitable number of large cinder blocks that you can build up as high as you want. Generally high enough to lower the unit all the way down and still have a few inches of clearance off the ground. Don't want to go TOO high for stabilities sake !

This system also allows you to very easilly roll the boat onto the other side of the bottom that you're not working on to give you a bit more height and better angle for that horrible blister job that you have to do.
Believe me , you'll greatly appreciate the extra few degrees that you get doing it this way.

Steve

MOP
10-18-2007, 07:43 PM
Steve for working on the bottoms of small boats you can get away with three point, we block at the transom corners so the load is carried by the transom and by the sides. I agree jack stands can and will dimple a bottom, I much prefer hard blocking but even that not correctly placed will cause issues. My 22 sat on three points for about 4-1/2 months while I worked on the bottom I guarantee no ripples and the keel is dead straight. I bet we have 15-20 small boats sitting in the yard now on 3 points.

Phil

vonkamp
10-18-2007, 09:25 PM
Speaking of hull supporting, I found these pic's of a 63' Magnum for sale @ 1.5m. If this were my boat shored up like this I would NOT be a happy camper. :eek!:

My boat is sitting on some rolling supports that can be adjusted higher or lower by changing the bunk support bars. Might be an option if you are on concrete and need to move it around.

Hmmm. Tried to post a pic of my boat on the roller supports but it said I had allready posted that pic. Why can't we post the same pic twice??

mrfixxall
10-18-2007, 10:54 PM
Speaking of hull supporting, I found these pic's of a 63' Magnum for sale @ 1.5m. If this were my boat shored up like this I would NOT be a happy camper. :eek!:
My boat is sitting on some rolling supports that can be adjusted higher or lower by changing the bunk support bars. Might be an option if you are on concrete and need to move it around.
Hmmm. Tried to post a pic of my boat on the roller supports but it said I had allready posted that pic. Why can't we post the same pic twice??


Boy that looks real safe,,what are thease people thinking:bonk:

Pismo
10-19-2007, 08:49 AM
I agree with 3 point as well. Make sure the rear two are long beams running fore-aft that catch the full thickness of the transom, never sideways or you can get a hook in the bottom.