Remove shields from repair ships.

[Nerva]

Or.

4000 Nanobots.
0 Shield Batteries.

Possibly nerf their hull to "vulnerable to double razor" levels or so.

Problem solved.

This is a simple solution to the problem that seems to work, at least locally. It's a bit quirky*, though. Don't know if it works in Multiplayer.

*Shield Batteries still show up as purchasable item but actually buying them is not possible.