Decided to try this unusual option. Positives: good comms from the owner - email with instructions and codes to get through the gate then enter the “boat/room”. The keypad on the door of the boat is not great as the buttons stick. It took 4 tries to get in.
The boat is small and compact but well maintained.
Alas for me I stayed on a windy night - the outside hammocks on all of the boats are a nice idea but they clattered against the boats all night making such a noise it was hard to sleep. The bed scores 4/10 comfort. Overall, sadly, for me, not worth the price. Would I stay again? Truth is had it been a lovely day, nice weather/then probably yes - being on the water and feeling the boat rock was very pleasant. The views of the Rock are great. But comfort level is pretty low. I’d be tempted to stay in summer but not in winter - that noise from outside banging of the hammocks was terrible.