User:Melllvar
Outer flat ring can be used as a dock for small boats, or can be absent if it makes the structure cheaper or stronger. Doors at water level with ramps allow structures to be deployed and recovered easily.
Spherical Seastead with 1 water-level door & top hatch
Saucer Seastead with 4 water-level doors
Floatable platform to act as bridge, dock, or land