OK .. its a bitch to find out where the water gets in... the last three RIBS I've had all suffered from it
So you know its fresh water by tasting it ? then its some surface mounted article like a console or a deck hole where some cabling goes through the deck.. not only that .. it could be some console component that you leave uncovered.. though you said the boat is partially covered,..... whats left exposed ?
Its a process of elimination.. can you see into your underdeck? what area gets wet first? Can you silcone off any of your deck structure ? additinally to what you can see
The most DIFFICULT one I've ever had was the U bolt in the bow... whilst at anchor the boat filled with sea water
very slowly, .. before I discovered the damn bolt was leaking water into the boat as the supplier had not fitted it right
just work your way through the options