hull

Catamarans consist of two parallel hulls connected by a single deck, and range from lightweight boats used in Olympic sailing, to huge passenger ferries.

The species has colonized new regions when transported on ships’ hulls or in ballast water that is drained in ports.

In each country where the mussels have taken over, the initial introduction also appeared to be from ships — on the hulls or from ballast water release.

They had pounded on the side of the hull trying in vain to get attention of the world outside.

The hull’s material attracted the most attention - it was made from layers of carbon fibre mixed with resin.