 Flooding of the rudder room should not have sunk the ship since there was a watertight bulkhead.The NTSB can only speculate that the door was left open, the seals or latching dogs failed, or that the holes cut in the bulkhead for refrigeration lines needed for fish processing were not watertight.If the conversion had installed a watertight bulkhead between sections of the fish processing area the ship would not have sunk.