Clark Lindsey reports on another reference spaceship design, the Space Coach, which was first described in a paper published in the Journal of the British Interplanetary Society. In a real sense, this would be a water rocket. Water plays a central role in its propulsion (the rocket part) as well as crew safety and life support. The authors liken the spaceship is stagecoaches that helped develop the Western US.
Poke around their website. It is quite interesting and is unconventional when compared to the metal capsules that come to mind when most of us think of spaceships.