Just received my Petrel kit and already stuck on building the strongback. I have diagrams with no measurements except one and I can't find a specific example in the book. I believe it's supposed to be a total of 12' long per the one-sheet diagram provided.

Here is what I have (wood parts) for building an internal box beam (advanced apologies for dumb questions):

4 x 8' side sections

2 x 4' side sections

3 x 8' butt joints

2 x 6' butt joints

2 x 2' butt joints

So this looks like a total of 40' in length each for sides and butt joints. Divided by 4 (sides to a box), that means a total of 10' length for the box beam. This disagrees with the only length measurement I have for the box beam. I've checked the kit contents and it doesn't look like anything is missing. So I am confused. Plus ....

Questions:

1. I know I am supposed to stagger the pieces for strength. Am I supposed to cut the sections and if so which ones to what length?

2. What the &*^%! are butt joints and where do they go? From the book, it looks like butt joints are for external strongbacks and not internal.

I either have too many pieces or not enough. Any and all help would be much appreciated.

Thanks,

Jen