Inwale screws

[Phildub]

Hi team.
I'm a virgin boat builder, having a go at a strip canoe. I'm at the stage of fitting my 20mm (~3/4") scuppered inwales. The instructions I have say to use 1/2" #4 screws to fix them to the hull and 1 1/4" #8 screws for the outwales.

I have 2 questions:
1. a #4 screw seems quite lightweight. Is there any disadvantage using a heavier gauge screw such as a #6 or #8 (maybe more chance of splitting the wood?) or is the #4 sufficiently strong to hold the inwale until the larger outwale screw goes right through the whole lot?
2. Do people recommend stainless screws or can I get away with galvanised (cheaper). My cabinetbuilder mate says stainless can be more brittle going into hardwood and he's had the odd one's head shear off, so I want to get this sort of detail right!

Any advice appreciated :o)

[Cruiser]

Jim will wade in on this, he uses scuppered gunnels, so he has the experience to comment.

Brian

[Patricks Dad]

I would not use galvanized screws. Silicon bronze are common. Drilled and countersunk to avoid high torque situations. I however have never screwed my gunwales in place. I apply them with thickened epoxy only. If you have plans on removing your gunwales, screws is the way to go but if you don't intend to take them off, just epoxy them on.

[Cruiser]

I am in the "epoxy them in" house as well ... i view screws as extra weight and I don't ever plan on removing gunnels.

[Jim Dodd]

Every builder has their method and reasons for it ! I guess that's why they don't all look alike !

I'm in the camp of glue and screw my inwhale, and glue my outwhales. That way there are no screws showing. No places for moisture to get in and cause rot.

I premount my inwhales with #6 Stainless screws. They need to be short enough, not to stick through the inwhale, when torqued down. I don't use the screws for strength, but more to aid in attaching the inwhale to the hull ! I work alone, and a cordless screw driver ( drill) is my friend. It quickly and accutately gets the inwhale in place, while I add clamps where needed a little later. The screws actually reduce the amount of clamps needed.

I then disassemble, and apply mixed epoxy, to the hull side of the inwhale. After a few minutes, I apply thickened epoxy on top of the previously applied epoxy. The first coating allows the epoxy to soak in and form a good bond.

Then I assemble.

I Cap my hull, covering it with the outwhale. Gluing it on, using the same method above, but without screws.









I hope that helps ! If not keep asking until I get it right !

Jim

[Phildub]

Awesome thanks guys. That's some impressive work Jim! I really like the capped outwale! I haven't seen that before, but it makes a lot of sense.
I ended up screwing with #8 stainless screws. I didn't feel I had enough clamps to epoxy only :o)

[Jim Dodd]

Capping the gunnels made a lot of sense to me too.

It prevents moisture from getting between the Cedar hull. and fiberglass.

Plus I like the clean look, of no screws showing.

Jim