Glue for solid wood transom

Welcome to the new Bear Mountain Builders Forum - an interactive internet service we provide to encourage communication between canoe and kayak builders
Post Reply
cff
Posts: 33
Joined: Thu Oct 07, 2010 5:45 am

Glue for solid wood transom

Post by cff »

Hello all. I've just subscribed after years of lurking. I'm currently buildng the rice lake skiff for use as a car topper. I have a concern regarding using yellow glue on the lamination joints on the solid cedar transom. Will yellow glue be up to the task? My blank is glued up with the carpenters glue but is not shaped yet. Should I use epoxy with spline or tongue and groove joint? I still have time before it too late. I'm thinking the yellow glue will be strong enough after it's encased in epoxy and glass. Any advice will be appreciated. cf
User avatar
Glen Smith
Posts: 3719
Joined: Sat May 08, 2004 9:08 am
Location: Baie-St-Paul, Quebec, Canada

Post by Glen Smith »

Yellow glue will provide a joint that is stronger than the wood fibers. Adding fiberglass and epoxy will increase the strength and protect the wood and joint.

However, if you intend to use a motor on this boat, even an electric trolling motor, I would suggest using a hardwood for the transom. You also need "knees" to reinforce the transom to hull connection.

One fellow came to see me with his Rice Lake Skiff on which he used a 50 pound thrust trolling motor and he had hit a rock with the prop while in reverse. The result was the transom broke away from the hull at the top because of a lack of reinforcement.

I hope this is helpful to you.
cff
Posts: 33
Joined: Thu Oct 07, 2010 5:45 am

Post by cff »

Thanks for the info Glen. To answer your question if I'll be using an outboard.. Yes. I have a 3hp that I'll be running and it'll likely be rocky where I intend to go. Maybe I'll laminate with plywood and veneer over with cedar. I'm trying to keep the weight down to a minimum as I'll be cartopping. The cedar blank is planed down to 1 1/4" as per the plans instuction. If I'm going to stick with what I have already then I read your post as saying the glue joint is fine. I had planned on adding knees to the transom to help strengthen it. But adding a motor raises issues with rock strikes, etc. Perhaps I can add an additional layer of hardwood at the top where the motor will be clamped on to act as a pad that stretches from gunnel to gunnel? would oak work? (I have a stock of air dried)
User avatar
Glen Smith
Posts: 3719
Joined: Sat May 08, 2004 9:08 am
Location: Baie-St-Paul, Quebec, Canada

Post by Glen Smith »

White oak works fine.

You have to imagine the "worst case scenario" and build to withstand that.
You should also wrap the transom to hull joint with a few layers of bias-cut fiberglass both inside and out.
cff
Posts: 33
Joined: Thu Oct 07, 2010 5:45 am

Post by cff »

So if I decide to use the transom as it sits now I could rout out a slot to epoxy in a piece of oak that I could orient the grain verticaly to take the strain of the out board. If it was 4-5" wide and 3/8ths thick it wouldn't add too much weight and still add a significant amount of strength to the transom. My motor only has one screw clamp so it doesn't require a huge area to clamp to. I could even add a peice of oak in a T shape maybe with a half lap joint at the top. That might do the trick. I want to keep the weight down so I can handle it by myself when loading/ unloading ....
User avatar
Juneaudave
Posts: 522
Joined: Sat May 08, 2004 12:42 pm
Location: Juneau, Alaska
Contact:

Post by Juneaudave »

Hey cff...Welcome in from the lurker world!!!

In the for what it's worth, I have had a Rice Lake for a few years now that I run with a 3 hp and haven't had problems. I made my transom out of mahogany, glued up with carpenters glue, and glassed on both sides,

The area I have the most concern with is fitting and glueing in the transom. There isn't much there holding that transom in and you need to do a good job.

Image

So...like Glen recommends, take some time...get the knees to fit well, glass around the outside joint, and as a minimum, put a nice fillet inside.

Image

Once finished it will be fine. If I were to do something different, I would mount a small 1/4 inch thcik or so aluminum transom plate where the motor mounts. Over time, I have had some abrasion from the vibration of the motor, and from taking it on and off.

Image

Enjoy your project and new skiff...Juneaudave
cff
Posts: 33
Joined: Thu Oct 07, 2010 5:45 am

Post by cff »

Thanks for the input guys. I will reinforce the transom with the oak and then laminate some mahogany over the back of the transom. Does anyone have any input on width of strips? I bought wrc at a great price (2X6) and milled them into 1.5" strips. The plans call for 1 1/8- 1 1/2" strips. I think I coud get away with using the 1 1/2 from the gunnel up to the bend. Approx 4-5 strips. Any advice on that?
Juneaudave. Nice boat! You used solid gunnels. Would you build them like that again?
Cheers guys. cf
User avatar
Juneaudave
Posts: 522
Joined: Sat May 08, 2004 12:42 pm
Location: Juneau, Alaska
Contact:

Post by Juneaudave »

Thanks cff...I think you will find the Rice Lake pretty easy to strip. The shape doesn't really torture the strips like some canoes do. I was looking over my pics, and it looks like I went with 1.5 inch strips for the whole thing. except for some accent strips. That size strip looks appropriate for the size of the skiff. Looking at the pics, I might have used 3/4 to close part of the football, but that is painted and I can't tell. I did use a scuppered gunnel, but it is solid where it tapers to the transom and bow. The pictures kind of fool you. Have fun!!!
Post Reply