Builders' Forum Archives
Re: Glassing deck - or no
Posted by Howard on Mar 21, 2005
I would glass the deck.
When I built my lt 17 they did not have deck glass as a standard kit option.
While you will save weight by not glassing the deck, it is less durable and more suceptable to water intrusion into the core, particularly around the nails and the deck edges, compared to a boat that is glassed.
I think it was these issues of durability expressed through the feedback of a lot of builders that led them to add deck glass as a standard option...they certainly didn't do it so they could say they could sell you a heavier boat.
When I refinished my LT17 last year, I added deck glass. I can tell you from experience that it is easier to add deck glass during the initial build then after the fact. I have noticed after the refit that it handles the average paddle strike and bumps on the shear much better than before the deck glass. Before the glass it did not take much of an impact to expose the end-grain of the deck
There are many ways to get the boat done in the low 40lb regime without sacrificing any strength in the right areas for normal paddling. But going without deck glass is not one of those, in my opinion.
Given that your real concern seems to be weight, here is a compilation of 10 ways to save weight without sacrificing strength where you want it for "normal" use that i have gathered over the years from personal experience and the folks on this forum:
1) meticulous detail to filleting the hull seams and bulkheads...building them any bigger then necessary adds nothing but weight.
2) meticulous detail to glassing the hull to minimize the amount of epoxy. use a squeegee to ensure the glass/epoxy is tight on top of the surface. eliminate drips and runs
3) extending the shear clamps to the ends and not overdoing the end pours. again, big blocks of epoxy sitting in the ends really add nothing to the durability of the boat.
4) attaching the deck without nails.
5) routing/rounding over the inside bottom corner of the shear clamps...i routinely round with a 3/4 inch router bit.
6) make the shear clamp 3/8 inch proud of the side panels (if you are doing nailless construction, otherwise the nail will pound through) to minimize the amount of material in the shear clamps after you plane them down. the shears are really most important to give you an interface to which to attach the deck. boats with different deck attachment techniques have no shear clamps...becuase the strength is mostly coming from the corner that is created.
7) generously round your shear edges, chines and inside edge of your coaming. not suggesting to overdue it...but i have seen a lot of boats where these edges are almost sharp. properly rounding them over removes material (making the boat lighter) and makes the edge more capable of sustaining impacts becuase the impact is spread over a larger area.
8) when installing deck glass only overlap the glass 1/2" below the deck edge. going any farther is not improving the strength or impact resistance of the chines...its just adding weight.
9) remove the copper stitches. use the "tabbing technique to secure the hull and remove the stitches. this also makes it a bit easier to get smooth, minimum sized fillets.
10) if not building from a kit, select the lightest panel of the appropriate grade wood. even within the same batch of 4mm okoume, there is variation from one panel to another. bring a scale and pick the lightest pieces out of the batch.
there are ways to get even lighter...but these 10 are "free"...the rest start to involve more tradeoffs of either function or strength in my view.
best of luck
In Response to: Glassing deck - or not? by Jon Loraine on Mar 21, 2005