a watertight partition built across a ship from one side to the other. A ship canhave more than one bulkhead. For example, a collision bulkhead is one built in the front of a ship, designed to prevent flooding and the consequent sinking of a ship which has had a hole smashed into the front of it. Where there are bulkheads running across other parts of a ship, then there are watertight doors fitted where access through the bulkhead is required. —Welcome to the SO Glossary Final approval 2-Mar-90