Ramships can't move from a dark nebula into an adjacent light one and vice versa. Nebulas also tend to be full of rift zones, which ramships appear to be totally incapable of pathing through. Altogether, ramship fleets are extremely hard to move around in spite of the speed advantage that capital ramships enjoy over starships.

george moromisato 23 Mar 2015:

If a dark nebula and a light one are adjacent, there might be a tiny gap, which the ramship interprets as a normal space (and thus a blockage). We should deal with this by having some minimum distance that ramships can pass through.

george moromisato 16 Jun 2018:

Fixed with new nebula implementation.