Anyone can get lost on a boat. But to get lost in one, you need to be on a superyacht.

On a blustery midsummer day in Falmouth, Cornwall, the epicentre of the UK superyachting industry, I am casting around an interminable carpeted corridor looking for an unlocked door. If it leads to a guest room I’m pretty sure I’m on the second floor (of five). If I enter a massage room (there are two), any of the lounges (three), a kitchen (four), one of the TV rooms (three, including the cinema), a dining room (two), the spa or the gym, then I’ll have to rethink. 

Everywhere, clues torment me. I can’t be in the crew quarters — too much brass, the carpet is too thick and there is no call, surely, for a hand-painted ceiling mural of a medieval navigator’s map for those below stairs. There is no sound of the engineers clanging around in the engine room (which takes up two floors and is bigger than most London houses). The lift would help me orientate — I entered it through a lobby with a massive chandelier — but there is no sign of it now.