Britain's largest ever warship squeezed out of its tight dockyard yesterday (Mon) to take part in sea trials. HMS Queen Elizabeth, which weighs 65,000 ton, slipped out of the Rosyth dockyard and was pulled through just 14 inches of clearance by 11 tug boats. After undergoing hours of checks in open water, the aircraft carrier edged along the Forth and under the three bridges. The process of removing the Queen Elizabeth from dock was complicated.