Strongback Design

jpowers123 · Post by **jpowers123** » Tue Jul 28, 2009 9:56 pm

I just build my strongback and noticed that while it seems sturdy enough, it sure seems as though a center leg on the 16 foot span would make it a bettter design. Has anyone noticed the same or is there some particular reason a center leg would not be a favorable addition. Other than that it sure sems like a cut and dry way to put together an easy to make strongback. I originally had the older version of Canoecraft and I was very worried about trying to find a two 16 foot long board that was straight and true and then trying to hand plane out any imperfections. This is definetly the way to go.

mtpocket · Post by **mtpocket** » Tue Jul 28, 2009 11:54 pm

Currently, I don't have a strongback. I thought I was done building and so I made firewood out of it. I did however save the legs. I'm getting ready to reconstruct it for another boat and it will again have three legs. I've seen every imaginable strongback design known to man on the internet. Two legs, three legs, doesn't matter. What matters is that it is stable and strong enough not to sag over the life of the project. A 1/4" of sag in the middle would make the greatest looking canoe paddle like a barge.

jpowers123 · Post by **jpowers123** » Wed Jul 29, 2009 12:02 am

That was what I was thinking. I think I will add a third leg in the middle to try to prevent this. Also, is there any point in leaving string lines up to periodically double check the flatness of the top? Or is that paranoia? I would hate to get half way through the build and find out I had a progresssive sag developing.

mtpocket · Post by **mtpocket** » Wed Jul 29, 2009 12:10 am

Nope, no need. You could always look down the side of the forms and sight the sheer lines. Any deviation will show up. With the third leg, I would seriously doubt sag will occur. Another thing to consider is to mark the leg position on the floor. This will give you a reference point to look at periodically to be sure it hasn't moved from where it was originally. I did this so I would know where ground zero was in case I bumped it or had to move it for some reason. Masking tape or pencil marks will do fine.

Jim Dodd · Post by **Jim Dodd** » Wed Jul 29, 2009 6:44 am

I use the (T) top instead of the box beam. I won't say its better, it's just what I started with. Built it with 2x lumber.

I have'nt had any trouble with sagging, but I put wheels on one end, so I could roll it outside for sanding.

As far as the strings go, if it does'nt bother, I'd leave them on. Once your half way, changing the stations would be pretty tough.

Good luck
Jim

Post by **Patricks Dad** » Wed Jul 29, 2009 7:05 am

I built the canoecraft design but added a 3rd leg for stability. It worked great. I glued the whole thing to the floor to avoid it moving around. It's still there years later...

Woodchuck · Post by **Woodchuck** » Wed Jul 29, 2009 8:18 am

Yep, I added a third leg right in the middle... marked the floor then added hot glue and locked her down... No problems...
:smile :smile :smile

Big Woody · Post by **Big Woody** » Wed Jul 29, 2009 5:47 pm

I used three sets of legs.

So far so good. I'm also using that weight set, just like I promised.

vann evans · Post by **vann evans** » Wed Jul 29, 2009 8:35 pm

I actually made the strongback bottom/base in 2 sections -each is 7 feet long. they are made so that the 3/4 plywood top is screwed to the base in 3 pieces so the middle piece of plywood bridges the gap between the two sections. This way, I can easily disassemble it for future use. I mounted it on 3 sawhorses that I built specifically for the strongback-just wide enough and just tall enough. the sawhorses are built 1" difference in width so that they stack when not being used. It is incredibly stable . I used shims as necessary to level the strongback and screwed the strongback to the 3 sawhorses. The entire system worked great.

I'm sure there are lots of ways to construct the strongback-as long as it works and is stable . I wanted one that could be stored, stable and reusable.
Vann Evans