Thursday, April 13, 2017

Don't call it a comeback!

Actually I wanted to call this one "don't call it a strongback", but it is called a strongback! A strongback is a stabilizing component for boatbuilding. It looks like a ladder but serves as a platform for the plywood or a form to attach the stations to.

First, I had to get supplies. After some careful planning, I decided to rent the truck at Lowe's and get all of the supplies that I could for the known projects. At $21 to rent the truck, I can get that as often as I want to without exceeding the cost of buying a truck, but I still wanted to be efficient with my rental dollars. Here's the haul:

in my shop, plywood and lumber
I ended up being short by two 2x4's. I got the following list of supplies:

  • 1 3/4" plywood for the strongback
  • 1 5/8" plywood for the strongback
  • 2 5/8" plywood for the canoe forms
  • 2 1/4" plywood for the pirogue
  • 5 (should have been 7) 2x4's for the strongback
  • 1 1x8 pine
  • 1 1x3 pine
  • 2 1x4 pine all for the pirogue
Building a strongback

To put together a strongback, start by cutting the 2x4's into 18" sections. The most solid designs start out with laminating plywood strips. Pick the overall length of your strongback, and cut the plywood 5 1/2" wide. I wanted 2 layers, a 5/8" thick and 3/4" thick setup screwed together to get to 20' long. This meant I needed 5 strips of each thickness (with one cut in half) and 14 of the 18" 2x4 pieces. Making the strips 5 1/2" long leaves enough height to add stabilizers on top. Place the 2x4's spaced exactly 18" apart, then flip the whole thing over and put more 2x4's spaced 20" apart. 18" and 20" are the most common spacings for the canoe stations.

Cutup plywood and 2x4's

First side of the strongback, 18" apart

I nailed through the thinner piece of plywood with framing nails, then used 1 1/4" exterior screws to attach the outside plywood strips. I cut one strip of each thickness in half, so each side had two 8' sections and one 4' section. By the time everything overlapped it became extremely stable, even with only one side of the 2x4's in place. Now flip it upside down.

added the stabilizers

added more 2x4's spaced 20" apart on the top side

I wear a bunch of red shirts. these pics are about a week apart.
This thing is a real workhorse. A good solid strongback provides a platform for all of the other boat building activities. Most people are not going to build a canoe longer than 20', so I figured that would be long enough for me. I can layout a couple of sheets of plywood on there for the pirogue, and it will hold the stations for the canoe. It's a reusable component that will serve me well for many boats to come.

Up next, it's time to start making the Piragua!

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