This is a yacht. At least it is a wind powered boat.
Strictly speaking, this is a rotor or Flettner boat. Power is provided by the wind catching the central tube which spins powered by a motor in the hull. You can read more about the concept on Wikipedia. To be honest, the physics is a bit of a mystery but I'm fascinated.
The boat appeared in our clubhouse along with the modelling bits and bobs from it's builder, Graham Bran, who has sadly died recently. I remember seeing him experiment with this in the water as well as his 2-tube follow up model. At the time we chatted about it which pointed me towards doing some research.
For the moment I've tucked this boat away in store but one day I want to carry on his work. For the moment it's safe. Let's face it, I'm probably the only one in the club daft enough to want to give it a go!