Splitting a GRP Hull.

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trebor
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Splitting a GRP Hull.

Post by trebor » Thu Jan 23, 2014 10:06 pm

HI all, I would like a few tips regarding taking the deck off a GRP hull.
Robert
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Re: Splitting a GRP Hull.

Post by Rupert » Fri Jan 24, 2014 10:24 am

So long as you aren't wanting to put it back on again after, it is pretty easy.

I'll see if I can dig out a webpage that shows it being done - I saw one recently, possibly on Rod Mincher's website - http://www.earwigoagin.blogspot.co.uk/, where a Laser is butchered.
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trebor
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Re: Splitting a GRP Hull.

Post by trebor » Fri Jan 24, 2014 6:16 pm

Hi Rupert, I was hoping to put it back together, how is it actually put together? I can see that the join appears to be sealer of some sort, where else will the top touch the bottom? also I can see a join inside the dagger board housing.
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Re: Splitting a GRP Hull.

Post by chris » Fri Jan 24, 2014 6:47 pm

Interested in people's ideas on this.
Amy wants to take the Toy apart to sort out the problems inside the hull.
The two parts are riveted, glued and then an ali band to cover the seam. I expect getting the band and rivets out is straight forward. I was thinking that the seam will have to be sawn apart to avoid too much damage. Possibly a hacksaw blade in a handle, but a Japanese saw without a stiff back might be good too. I think that will work all round the edge but when it comes to the bit round the centreboard ....that could be the tricky bit.

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Re: Splitting a GRP Hull.

Post by Rupert » Fri Jan 24, 2014 9:05 pm

Not something I would ever attempt.

Most boats with a laser style arrangement of deck and hull are fixed down on a bed of polyester gunk. Even where this is split and leaking in places, the chances of getting the whole deck off in one piece without damaging the hull or deck would seem pretty slim, and round the case area I'd not know where to begin.
Rupert

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Re: Splitting a GRP Hull.

Post by neil » Fri Jan 24, 2014 10:43 pm

The ToY should be straight forward. My old boat had the deck from another boat on it. The previous owner removed the rivets, flipped the deck off and rebuilt the interior structure. He then glassed the new deck on, creating a rolled gunwhale.
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Re: Splitting a GRP Hull.

Post by JimC » Fri Jan 24, 2014 10:46 pm

Rupert wrote:Not something I would ever attempt.
I concur.
If you were really desperate to give it a go then I suggest trying to acquire a scrap hull and practice on that first.

Jim C

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Ed
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Re: Splitting a GRP Hull.

Post by Ed » Fri Jan 24, 2014 11:57 pm

A laser would as you say would scare me....

but something like a Toy is normally pretty easy. It depends on how the halves are attached together. If there is an overlapped join, they can be hard, but if it is a face-to-face join with rivets/screws, then not too bad. They have rivets cos they seem to need them. In fact it is often the rivets and the alloy trim which hold them together, cut those out, give it a shake and a tap and they may well fall apart. If not, then I reckon just prying them apart will most probably free the top from bottom.

Not sure I would want to take the decks off a minsail sprint either come to that.

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Re: Splitting a GRP Hull.

Post by rme_01 » Sat Jan 25, 2014 12:40 am

I am curious to know why you want to split it in the first place. If it is to repair a hole in the hull then there are other less drastic ways.

Robert

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Re: Splitting a GRP Hull.

Post by JimC » Sat Jan 25, 2014 6:59 am

rme_01 wrote:I am curious to know why you want to split it in the first placed
There's some major work that's definitely easier... In my own case I need to put a new bottom zon my glass Moth, and that would be spectacularly easier with the deck off. But I'm not brave enough. Leaky centreboard repairs or anything involving plywood rotted out between the mouldings are things that occur to me where it would be really nice if you could part the halves without risk. The alternative is chopping holes and doing keyhole surgery and then you're faced with making the gel coat good. Its a much smaller issue on a painted boat of course.

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Re: Splitting a GRP Hull.

Post by Rupert » Sat Jan 25, 2014 11:59 am

I suppose if you had 2 hulls, you could take the hull off one and the deck off the other - destroying one hull and one deck wouldn't matter. What boat is this you are thinking of? If it is the Minisprint, and you are looking at the centreboard joint, then you'd do better to take a grinder to just that part of the boat to do a re-build, rather than the whole boat.
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trebor
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Re: Splitting a GRP Hull.

Post by trebor » Sat Jan 25, 2014 12:26 pm

Hi, the boat in question is a Laser, the Hull to Deck join had completely failed down both sides at least 8 feet, probably from years of bumping side, we pumped Sikaflex in to joints and clamped, it appears to have worked, it just seemed to suggest a simple way to do awkward repairs.
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LASERTOURIST
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Re: Splitting a GRP Hull.

Post by LASERTOURIST » Tue Feb 11, 2014 9:35 pm

Some lasers had the bad glue disease (end of the irish production in Waerford and PS going into recievership at the end of the 80's) and the epoxy glue tended to disintegrate but even like this taking the deck out was very difficult : the mast chimney molded with the deck is is glued in the mast support (parrt of the hull piece) there is a lip on the deck piece that is glued on the CB case and another glueing point at the bailer thing in the cockpit.

On some other boats it can be done : the Lanaverre 420 foredeck and sometimes the keel piece on the MK2 lanaverres (the MK1 had a wooden keel bit ahead and behind the GRP CB case) wre bonded with resin only so if it is a bit cracked and dried it can be taken off carefully , with a wood chisel and wood wedges, have the surfaces sanded anthen rebonded with fresh resin + chopped matt (dubbed Choucroute - sauerkraut in French boatbuilder lingo).

Sometimes there is only a few inches of weakened bonding so the seal can be opened partially, sanded (an electric file is handy) and rebonded .

Depends of the type of bonding joint , too , the shoe box type is weaker than the rolled lip gunwale sort of thing , but it is easier to open and reseal

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Re: Splitting a GRP Hull.

Post by Ed » Wed Feb 12, 2014 9:56 am

Chopped Matt = sauerkraut

Brilliant!

eib
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