boat building


Senior member
Mar 12, 2004
how is a grp boat built?from start to finish
what materials are used,where are they used how are they used how are the stringers made how are they fastened in etc etc etc etc
Starting with your waxed mould, a gelcoat is applied,typically by brush, but can be sprayed.
A second coat of gelcoat is applied after the first has gone off. once this has gone off, the CSM can now start to be layed, 4 or 6 oz down first, then once cured the rest of the CSM can be applied.
Woven Roving can then be applied to the hull which strengthens up everything especially the transom,chines & keel. Transom timbers should be laid onto wet glass, then glassed over to encapsulate it so as not to let in any moisture.
Stringers are fitted, these are most commonly a closed cell foam, shaped and glued to the hull then glassed over and capped off with UDT. The boats floor can then be fitted and bonded in, usually 3/4 ply.
The boat should be left to cure in the mould for a couple of days but i dont think many boatbuilders do this due to lack of time and deadlines!!!
Then its time to crack it out of the mould, usually it is possible to use wedges on most hulls but can also float them out to prevent any stress on mould and or moulding.
I think i have covered the typical lay up on a hull, obviously this varies considerably with size and purpose of the boat.
how many layers of csm and woven are applied in total
dropped a bollxxx on last post

is the entire boat floor glassed over?
Depends on what size boat you are laying up, a 19 - 20 ft hull would be about 8 to 10oz lay up(4 or 5 layers of 600gsm) with reinforcing where required. One layer of roving.
why the reason the entire floor is glassed as opposed to just the edges where it joins the hull?
Because the floor is wood ant any wood needs to be glassed and flo coated to prevent moisture entering and rotting the floor out.
from what i can see of my floor it looks like its just glassed if that, can't see much due to the carpet
Like this


  • nuthinfancybuild002.jpg
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yes one layer but two layers around the edge where the wood meets the hull.
can the second layer of matt be layed whilst the first is still wet?
cheers gav
i ve got a bit to do at seems mr ring has missed about a foot of laminating on the hull-deck joint right at the very front of the bow!
Re: No glass

Captain Chaos said:

that's what i thought when i seen it.but there's no damage or anything like that,just missing glass about 12"if that so i'll just glass over the join like it should have been to start with!!!!

You canhave the best boat in the world but if it aint built properly..........
Sounds to me like it was built on POETS day!:drain:

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