Rotten core on forward deck, how would you fix it?

[wattaway2]

Just a thought you don’t mention the thickness f the deck but you can buy empty caulking tubes and get clear hose to slide into the void, nd onto the tube.iwould try getting some PCs ofstarboard or ? Tall enough to bridge the open gap(1/2) and 3/4-1” wide to except the screws for the new hatch temp put in place then install the hatch and drill mounting holes .remove hatch mark sides of starboard pull then cut a few slots etween the mounting holes big enough for the plastic tube to be pushed in then set up your filler in the tubes and go at it