You almost certainly have water stuck in that hull that boat is sitting way too low right over the whole hulls length
Maybe when u had the transom done and they cut your floor and stringers forward they have glassed over your drainage.. simply put they ...... up!
I have had 2 boats take on water 9ne of those had a 100÷ underfloor cavity filled with water and i can say your hull is well over 50% full of water