Magnetic deviation and currents?
 

Can anybody tell me whether magnetic deviation is modelled in SH3?

Also, are currents and other oceanographic effects simulated?

Thanks very much.

None of the two. Your heading can wobble due to wave action, but that's it. And that wobble get's added up over time when you use timecompression.

[EDIT]Any drift you experience seems to be the result of the helmsman taking a nap after it thinks it reached the commanded course. It won't stick to it unless you set a waypoint.

That's what I suspected, thanks for the confirmation Pisces - much appreciated.

Might have to look into modding this if it's not already been done :) (and assuming its not hard coded).