: I'm just getting started building the Great Auk. I have my forms ready to
: attach to the strongback, but I need (I think) to cut the forms which will
: breakaway in the cockpit area. I don't know where to make the cut. Help
: please!

Sounds like you want to remove the forms through the cockpit after you have attached the deck to the hull, and you are worried that the big forms won't pass thru the small cockpit opening.

So, for this you need two-part forms. Simple enough.

Draw a horizontal line through the widest part of the form --probably this will from left sheer line to right sheer line. You don't need to be exact with this . You have a wide margin of error here--probably 4 to 5 inches. Copy that line to the reverse side of the form

Get a few pieces of scrap plywood about 4 inches wide and 5 to 7 inches long, or find some short pieces of 1x3 or 1x4.

Screw two of these scraps to each large form so that they overlap the lines you've drawn. Put both blocks on the face of the form which is closest to the cockpit opening. One block goes on the left side, and the other goes on the right. Keep the screws an inch away from the line.
Now flip the form so the blocks are on the bottom, and set the cutting depth of your circular saw to the thickness of your form material, or a little bit more. Now cut along the line you drew.

You should cut the forms into two smaller pieces which are still attached to each other by those scraps you scewed on.

Assuming you made your forms correctly, they will retain the right shape.

After you cut open the cockpit hole you can unscrew the blocks and the wide forms will separate into two smaller pieces. Slice a chunk out of the internal strongback and the forms can slide off, and be removed through the cockpit.

Most of the time the forms can slide off the strongback and fit through the cockpit in one piece.

Hope this helps.

PGJ
Hope this helps