You have had sensible suggestions from lots of people
Like building the hull as 2 separate boxes that bolt together - theres pics on the thread links about different methods of doing it.
I pointed you towards a source of clips, fittings and hardware for accurately locating & locking the 2 parts together.
It's not actally very difficult as long as you can make strong, well braced, well sealed pair of bulkheads at the join that can but up to each other and locate accurately.
If the front part doesn't have any electricals, there's no reason why it can't be a free-flooding, neutrally boyant long 'visor' clipped to the front of the main rear floatation 'box' that has the batteries, motors & radio inside.