The drive unit should be no problem. I have seen a lot of installations where different makes of drive units are used without any problems.
The course computer simply provides 12v (usually) the polarity is reversed to drive the unit the other way. The drive unit will usually happily spin when connected directly to battery
. It just does not know when to stop, or drive the oppisite way.
Check the course computer can supply enough current
and that the voltage is the same.
reference units are normally specific to the computer, so generally these cannot be mixed.
What specifically is the model drive unit you have and what Simrad
unit would you get?