In order to stop myself becoming the victim of floating sharks jumping  onto the helm of my ship, i built a cage/enclosure around the  helm of my ship. However the sharks seem to become stuck in the flooring, ..or passing part way through the walls. or  leaping onto the deck and  getting stuck on the mast. If you kill the shark , it then rolls onto its back and becomes a weight that  de-stabilizes  your ship. The shark attacks seem to  occur after you release the helm controls to  either view the map or  eat. several times i have  moved the camera view back to see a shark tale sticking out of the  stern  of  my ship ...and then see the sharks head  emerging through the floorboards. This  seems to  be a materials porosity issue  as  the  building i  constructed will also "leak during" a rain storm,  even though the roof has decorated stone panels/marble  panels lining  it .