To have zero toe in/toe out and a square setup of the hulls/crossbeams do this...

1. Make a mark on the top aft of one hull then make a mark in the exact same place on the other hull.
2. Make a mark on the top bow of one hull then make a mark in the exact same place on the other hull.

3. Check your work. You now have four marks on your hull, the distance between both marks on the left hull should (and needs to be) the same as the distance between the two marks on the right hull, if not repeat steps 1 and 2 until you get it correct.

4. Setup up your hulls with the cross bars attached but without tightening the bolts snuggly, you will need to have a little slop for the next steps.

5. Measure the distance between the art mark on the left hull to the bow mark on the right hull.

6. Make the distance between the aft mark on the right hull and the bow mark on the left hull the same as the distance measured in step 5.

7. tighten the bolts

8. Check your work. Remeasure as in steps 5 and 6. If the measurements are the same from hull to hull/ aft to bow then you have paralell hulls and a square setup. If not repeat steps 5,6 7 and 8 until things measure out.

This is basic geometry and it works for anything that needs to be square or rectangular. The more accurate your measurements and the marking of the hulls the more accurate the results.

BLS