the positions of that mast and crane might be bad for helicopter operations. the only real landing spot you have right now is between the crane and the structure, but with the elevator aft I would like to have it opposite, with the crane near the structure and the landing spot all aft of it.
also, why is the crane sponsoned?
the hull would benefit from an bilge keel and I think one bigger thruster is better then 2 small ones.
other then that, interesting design and great drawing