A smaller ship for short range or small-scale missions, the Uutaruu runabout is a modular design that can be extended for additional crew or cargo. Many of the components have cognates with the voyager-class ships (see that post for additional information not repeated here). In fact, the runabout can be seen as the core of a voyager-class ship on its side. I did a rough sketch of the initial concept a few months ago. While the voyager-class ship is based on an air bubble rising in water, the runabout is inspired by a falling water drop or the rising central jet rising out of a one splashing down.
The bridge and primary passenger area is a simple sphere that is separable from the rest of the craft for emergencies or simply changing to a new mission. It has a spare hyperquantum computer but requires an additional power source if it is to operate independently of the singularity drive/power core. It’s a bit more cramped in the engineering compartment with pass-throughs among the equipment that the soft bodies of the Uutaruu can squeeze between.
The other distinctive feature of the runabout are the thermal control rods protruding out the back end of the vehicle. Since the ship is essentially the same as the core of a voyager, it lacks both the extended thermal surface area and the additional volume of water that serves to smooth out the fluctuations in a toroidal singularity drive. The singularities scatter past each other which creates different amounts of heat that needs to be dissipated depending on how many (and how big) singularities are in drive with maximum capacity requiring all rods fully extended.
Similar to the voyager-class ships, the runabout has a mirror-like surface for heat dissipation. It is similar in size to a galactic mission ionopter. It balances on its thin landing legs using an entropy gradient that creates balancing forces. This requires less computational power than hovering, so in turn uses far less energy. However, it uses sufficient energy to dissipate enough of the continuous power generated by the singularity drive to not require additional thermal control systems1. It’s quite an elegant solution.
An additional scale comparison is shown above — a voyager-class starship and the runabout. The landing / docking hatch of the two vehicles are capable of coupling to each other to allow beings to pass between them. An Uutaruu voyager can even carry multiple runabouts inside its passenger / cargo compartment. Often contained inside a large vacuum canister in order to account for water displacement, these runabouts teleport outside the voyager before continuing on their mission.
Update
Added a picture of the vacuum canister containing a runabout inside the voyager-class starship:
