VIDEO: Giant six-legged marine building vessel sails into Belfast Harbour in Northern Ireland

The MPI Adventure sailed in last night – a striking sight as the 20,700 tonne (deadweight), 138m (452 feet) vessel slowly headed for port.

For contrast, the Stenaline Belfast ferries have a deadweight tonnage of only about 6,000.

It is controlled by Middlesborough firm MPI Offshore, can accommodate 112 workers, and its six legs (which look a little like chimneys) can be lowered to the seabed so the vessel can stand on them like stilts while it pieces together offshore wind farms.

MPI Adventure at work

It is not totally clear why the vessel is in Belfast – it has not come to Harland and Wolff for repairs or refitting, as many other big rigs have.

It is thought, based on its berthing position, that it could be in port to collect wind turbine blades.