I concur with Et. However it sounds like you built it with staples into packing tape covered station forms. Now when you pull the staples the station forms are loose and move around. So far I am assuming all of this.

I would pull (disc sand) all the packing tape off the station form edges, and tack glue (with hot glue) them back in to the hull. Just enough spots of glue to hold the sheer in the proper place. Glass the hull exterior. Flip it over again and start building your deck. After applying 6 to 8 strips, hit every other form with a dead blow hammer (or any heavy, blunt instrument you got) to pop the glue. Put on a few more strips, and pop the glue on the other forms. Now when the deck is done you have very little holding the deck on, but enough to keep it in shape while you glass it and breaking it free is relatively easy.

As you proceed with adding strips to your deck it can be difficult to get a hammer into the tight spaces. I have a piece of galvanized steel about 15"x 1"x 1/16" you can slide an end into tight spaces wrap a heavy cloth around the free, hold on tight and give the middle a rap with hammer.

I have one these, that I ground all the teeth off. https://www.amazon.com/Vaughan-Bushnell-BS250D-Double-Handsaw/dp/B00004Z2X8/ref=pd_bxgy_469_img_2?_encoding=UTF8&pd_rd_i=B00004Z2X8&pd_rd_r=0JPQTCJR1QVJFG0QC8P4&pd_rd_w=x4AEn&pd_rd_wg=QAAr1&psc=1&refRID=0JPQTCJR1QVJFG0QC8P4

I slide it into tight areas to break the glue bond.