Hi Garry, my guess would be to at least nail, but I would glue and nail, making sure I tapped the nail heads into the wood. Good Luck!

Hi bicyclejohn, ok, I'll take your advise, thats no biggy to do, just seems everything would be stronger and straighter. Have you built a Great Auk? Boy, that sure would be a help if you did or if someone came on that has. Thanks again, Garry

The best option would be to use screws rather than nails.  They are more secure and it will be easier to take the strongback apart when you are done.  

I just started a petrel.  This is my first strip kayak.  I glued the plywood sides together with titebond and used a pneumatic stapler to hold the parts in place for clamping.  It worked great and is straight and quite strong.  One caution, be careful about cleaning up the edges of the plywood and make sure the joints are tight since the strongback holes in the building forms are exactly the right size so if your strongback is oversize you will ahve difficulty in sliding the hull forms over the strongback.