Why is my ship turning on its own?

[Suribachi]

No damage, no low fuel, no AI driving, no avoid torp, no avoid ship.  If I left it alone, the ships would start sailing in permanent locked circles.

[PhoenixLP44]

Thats a bug that tends to happen if you let ships sail in a straight line for too long. you should be able to resolve this issue by updating its course (just tell it to go forward again).

Why this happens however is a good question

[Suribachi]

Well that sucks.  Had this happen when I was chasing down some transports that were only marginally slower than my damaged ship.  I got up to go do something while I x10 towards them.  When I came back, my ship was reenacting the Bismarck's last stand.  Transport got away.