tigerguy, please review the rules and guidelines and try not to post into inactive topics, esp not to ask questions about your own boat in their topics. After 90 days w/ no new posts, topics are considered inactive.
It's been well over a year since there were any new posts to those topics you posted this into, and over a year since either member even logged on to iboats.
I moved one of your posts to a topic of your own about your LS, and closed the inactive topics
The tin boat fellas will be along to help and harass you.
Good luck and please post some more pix of your Nassau. It looks to me like it's got some corrosion (all that salty looking stuff) on the transom
And no, there's really no other way to install the transom plywood other then dismantling some portion of the transom, the fins or cutting them. The boat seems to have been built around the transom wood originally. Pix will certainly help..