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Permalink Reply by Roger Fletcher on December 14, 2009 at 1:25pm

Brian - You can accomplish the same going either way; however, you'll save yourself some money and time by building free-form. A floating chine merely means you don't anchor the chine to a frame, which is something you can do if you choose, regardless. The chnie is what I consider to be the keystone to the boat and serves as the anchor for the side panels and the perimeter of the bottom panel. The claim is that a floating chine gives the boat a little flex and may save from fracturing a frame if there is sudden and traumatic impact. Most guys will seat the chine with a polyurethane compound at the time they slip it into place. It's also no more diffciult to back the frames with a compound although I personally choose not to seal them above the water line. Just lazy, I guess, and the fasteners will do their work. Re screws -- I'm assuming you are using flat heads, perhaps SB or SS. To get them flush you will have to countersink them a dight-- which presents another challenge to the uninitiated: countersinkling too deep and lessening the ability of the fastemner to hold a thin 1/4" or 6mm panel secure. That's one reason I prefer to use ringnails on the panels. They anchor flush to panel and contrary to the opinions of some, they do not make repair work anymore diffciult should a frame fracture or side panel needs repair. I hope some others chime in.

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Permalink Reply by Brian Viergutz on December 14, 2009 at 7:56pm

Thanks for the reply Roger that helps a lot. So you use ring shank nails rather than screws in the side panel. Are they just galvanized or can you buy stainless or sealed brass? and what size do you like? It sounds like if I get the screws or nails flush with surface of the side panel the epoxy will cover the heads fine.

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Permalink Reply by Roger Fletcher on December 14, 2009 at 9:07pm

For that boat I'd suggest #14 1-1/4-inch silicone bronze ring nails. They're comparatively less expensive that other fasteners and they won't degrade over time.

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Permalink Reply by Brian Viergutz on December 15, 2009 at 3:43am

I think I am ready to go now. One more thing. Is there a reason not to use a mortise and tenon on the frames rather than a lap joint. I just like the looks of the mortise and tenon.

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Permalink Reply by Roger Fletcher on December 15, 2009 at 6:53am

If you want a flush union of the botton and side frames I'd suggest a rabbet joint. The joint was used by a popular builder in the Salem, Oregon area (John Ostrem). I've uploaded (I hope) a pix of his joint.

Attachments:

• Ken'sFrame.jpg, 68 KB

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Permalink Reply by Jeff Wilson on December 23, 2009 at 8:06pm

thanks for the pic Roger, it's a good example of a strong joint. Still looking over the plans of the 13 footer you sent me this past spring, and I still haven't started the model. All the best, Jeff

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Permalink Reply by Steve Sobba on December 15, 2009 at 1:28pm

Just finished my first boat ever..Don Hill 18' Fly fisherman... If I had it to do over I would have studied more or wished to have found this site... would give myself better center line points between bow and transom and secured those to maintain that centerline than just hanging by Rib number 5. Some kind of a modified strong back next time. I have a slight twist on port side at transom that I will have to live with. I like that rib lap joint also. Thanks for allowing me to throw my novice 2 cents in the pool. Steve

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Permalink Reply by Dave Z on December 23, 2009 at 8:11am

I would like to believe the lapped joint would be stronger than a mortised joint. With a mortised joint, you'd have to remove half the material from each peice to make a nice flush union. The traditional lapped method gets your more chine contact and more wood thickness.

I think building the frames might be a little tougher too. If you have ever built a set of frames, you will understand this. You have a flare angle where the bottom member joins the side member, and also the side bevel and bottoms bevels. If you did a mortise it appears you might have to do these bevels after joining the pieces.

Maybe it matters, maybe not. The mortise does look pretty nice, however. Just when you think you've seen it all, Ole' roger puts another pic out there.


Don't forget to pre-drill when using Si bronze nails and use a light hammer. Another trick is to nip the points off the nails when driving them in the pre-drilled hole. Especially into dooug fir frames. Doug fir has a varying hard/soft grain and will take a nail right through the soft grain if given the chance. By "blunting" the nail and driving it into a pre-drilled hole, it tendds to stay truer into the hole. In other woods, this may not be an issue.

I too, liek roger do not use sealant up the side members. The ring nails do plenty to hold that boat into shape against the frames. After several weeks on the frames the plywood will "relax" into its hull shape. If you knocked the frames out of an old boat, the side panels will likely retain their shape.

The main reason I use no sealant up the side frames is I hate the cleanup involved with polysulfide caulks. (and I'm lazy too) Your finishing job will look much nicer without stray caulk everywhere.

Good luck with your build. You are building a wonderful multi-purpose boat. Check my blog link, off site here, I document my total build last year and answer some of your questions above. You'll have to dig through the archives.

Dave

www.ththchronicles.blogspot.com

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