so what keeps it from leaking?

[Bob in Alabama]

Pardon my ignorance, this is all new to me. Buildiing a plywood 15 ft sailboat (featherwind/nutmeg). Other than making sure I have a good layer of epoxy between the chines and the bottom and the chaned and the sides, what keeps out the water?? I assume I need to caulk any gaps before I paint? But what caulk to use? Or I've read of thinkening epoxy and using that fill in any spaces.

Just using the boat for brief fun outings on the river and teaching the kids to sail, and it won't be living in the water, but in the garage.

Bob

[floatingkiwi]

Mate. I am surprised you are undertaking the building of a boat without knowing what keeps the water on the outside of it. Apart from posting more information and possibly pics or drawings, if I were you I would stop building anything and read some books for a start, before you waste a bunch of money and time on something that, if by the grace of God, manages to float, has a good chance of drowning someone.
No offence intended, just being as honest as I can with what you have posted. Good luck.

[James McMullen]

There shouldn't be any gaps between the chines and the bottom and the chines and the sides. If you have any gaps there, you haven't cut the bevels on your chine logs correctly--start over, or fill any gaps with thickened epoxy and add FG tape on either side of the seam to fix.

[2MeterTroll]

you wish BHOFM if she heard ya say that those oars would be in splinters before she was done :)

[Larks]

you wish BHOFM if she heard ya say that those oars would be in splinters before she was done :)

They'd certainly be in something!!!:D

[Greno]

The tight glued joint should not leak.

[Uncle Duke]

Buildiing a plywood 15 ft sailboat
Like others here I'm not sure where you would have cracks or gaps. How did you join the lengths of plywood to get to 15 feet? If scarfed, you should not have any problems. If butt-joined (with a backer) you also should not have any issues.
Where are the gaps?

[Ian McColgin]

Like others, I'm left with more questions. Much depends on how far you've gotten - whether we're offering good advice from the start or ideas of how to fix a mess.

In plywood construction, you don't use conventional caulking that accounts for the swelling of the wood. The wood is stabile. Think of it like aluminum and you're welding the plates.

So you don't want a "good layer" of epoxy in the sense of a thick layer. A good layer is a nice thin layer that keeps the well fitted bits together. As it happens, epoxy is the glue that can fill gaps rather well. Don't let that go to your head.

Make good fits to start for three reasons:

Epoxy is very different from wood. Wood can be bonded with thin layers of epoxy into nearly infinately lived "springs" but a thick pile of most epoxies (some exceptions) is not just more rigid than wood, it may even be brittle. Instead of a composit structure, thick layers of glue may give you two non-harmoneous structures competed for which will break the other.

Epoxy is really expensive. Anything you can fill with well fitted wood is cheaper than pouring the gloop.

Nice joints and good workmanship are your pride and joy.

So - let us know where you're at and what boat building books and other advice you already have at hand. And carry on. It can be made to float and those of us who learned later in life, secure that we were smarter (due no doubt to epoxy intoxication) than the old guys also have made things with some wavey plank lines and strange fills.

G'luck

[donald branscom]

Good fit up and good workmanship.
Then cover the outside of the hull with fiberglass cloth and resin.

Then when you are sailing it will be good seamanship.

[Bob in Alabama]

Thanks to all. Learning as I go here. I'm hoping to attach the bottom this week and just trying to understand all this ahead of time. No leaks so far!!

Bob

[donald branscom]

Thanks to all. Learning as I go here. I'm hoping to attach the bottom this week and just trying to understand all this ahead of time. No leaks so far!!

Bob
Yes I learned about PL PRemium plus on this forum. Good stuff and you can use it during the winter unlike epoxy. PL expands into the joint.

[Cuyahoga Chuck]

Most of us only have a limited number of boat plans in our heads at any given time so devulging the style of construction would help.
Glue and screw on a stick frame?
Stitch and glue?
Something new dreamt up by a guy on the "Duckworks" site?
The boat in my avatar is an 8' S&G pram. It leaks not a drop and shouldn't ever unless it falls of my roofrack while on the Turnpike.