Occasionally, when a ship crashes and is salvaged, the helm/hatch don't
respond properly. This is basically due to the ship not unloading properly,
and old/new data getting mixed up (this, incidentally, is why the salvage
office doesn't allow you to attempt to salvage a ship before the crashing
process is complete).
I've now added in a bunch of extra checks, to make sure things clean up
properly. If something starts going haywire, let me know