The simplest Federation spaceship is a planet-hopper – a module with a 4D drive.  Larger ships are made by fixing a planet-hopper onto something else.  A cargo ship isn’t much more than a huge box, with a planet-hopper stuck on top.  The planet-hopper’s 4D drive controls the whole ship.

In our mission on E-Dry 1, Tony was in a posh ship belonging to the Emperor of Nasti Nurvi 4.  It had four floors like a luxury house, with a planet-hopper on top.  See Report 17.

On Abble 3, we saw a luxury cruise ship, the Poseidon Explorer.  It had ten floors, with posh cabins, swimming pool, theatre, library, and lots more – with a planet-hopper on top. See Report 38.