Yes, the cap needs to come off. the floor material is actually attached to the bottom of the cap. The wood floor rotted because the manufacturers are cheap and only sealing the top of it, if at all. So it rots out from the bottom. Also any where a screw penetrates the fiberglass allows water in if not sealed. The boat itself looks fantastic, in my opinion. rojoguio will be a wealth of info, and if I'm not mistaken, has offered help already in your introduction of this boat. If you keep posting on the build, I for one will be following the build till it's done.
Proud to have served with and supported the Units I was in: 1st IDF, 9th INF, 558th USAAG (Greece), 7th Transportation Brigade, 6th MEDSOM (Korea), III Corp, 8th IDF, 3rd Armor Div.
1980 Ebbtide Dyna-Trak 160 Evinrude 65 Triumph