Dead air space or foam?

[nordicstallion]

Hi kids! While installing my new transducer & replacing the lazerat hatches I came across yet another concern, but first, I found a small crack in the transducer stem while replacing the old one. Now my sounder shows things Ive never seen before. New laz hatches are wonderful! I had to move my down rigger bases back a bit due to the larger overall size of new hatches & found that there is a closed space behind each battery compartment that I assumed were foam filled.The port side is a little smaller than stb so not accessible to install nuts on one rear DR base bolt so I had to use a large screw. The concern arose when I removed a small screw in the splashwell that held transducer & speed sensor wires. That little screw went into the aforementioned closed space.Water drained out for 5 min! On the 19 there's floatation in the wider gunnels & I drilled a small hole last year near the base & drained a lot of accumulated water in the floatation compartments. It's looking like ill have to remove both fuel tanks to access a point low enough to provide a drain for those aft closed spaces. I really don't need any water ballast tanks on the transome! Any thoughts or comments? Vern