Thread: Thwart risers

Opinion, backed by abusing a similar set-ups on a f/glass canoe & my Teal
without damage...

From the pics, it looks like breaking them downwards would mean punching a
hole in the sides. Unlikely. You'll probably break the thwart before the bond
breaks downwards.

You might rip them out upwards or sideways if you were to, say, suddenly lift
the whole boat by one thwart. If you added screws, you might increase
their resistance to that sort of abuse by maybe 20%, at which point the
screw heads tear through the planking. A fillet of pox putty under them would
increase the bond area & strength by maybe 20-30%.

It the thwarts will sit on the risers exactly as shown, you might want to insert
dowels across the grain. If the thwart ends fit flush to the planking and are
glued there, the dowels would be superfluous. Thru planking screws doubly so.

My two bobs' worth anyway.
rightly or wrongly....
cheers
Alan J

I agree with the previous POST,

Use the finish brads to hold in place until the epoxy cures and remove, I would add a fillet on the underside and if it will blend in on the top as well,

Jeff
vk4

Thanks guys you have confirmed my thinking just needed reassurance as the risers seem to me to be a very important structual element.

Pushing on regardless.

Now THAT's what was bothering me... risers? or ledges?

Originally Posted by b.o.a.t.

Now THAT's what was bothering me... risers? or ledges?

Well I don't know...they are refered to in the plans as seat risers I guess seat stringers another possible, ledges yeah maybe.

Re the structual bit I was possibly being a little misleading what I mean is there will be some vertical loading as the main traveller is spliced to the thwart knees not to mention crew weight.

I take it that these RAISERS are glued straight to the planking, as per your PIC,

I suggest that you can add a couple of KNEE'S under each side, this will give greatly added strength, and stability, to the Thwarts.

Added weight is minimal.

Jeff
vk4

Jeff,
Yes glued to the planks the thwart is also supported by the centrecase and there are knees to the side deck that I have also called wash boards (interesting).

The more I think about it a couple of screws through 6mm ply probably does not add a lot.

Cheers

screws would do 3/5 of 5/8 of stuff all, the glue will do more , i agree.

jeff