Working with some voyage data recorders and a couple of extra paths I think could be added that would be useful.

/vessels/<RegExp>/propulsion/<RegExp>/shaft/revolutions
Units: Hz (Hertz)
Description: Shaft revolutions (x60 for RPM)

It would be useful to have a positive and negative value for shaft direction (CW or CCW)

/vessels/<RegExp>/propulsion/<RegExp>/remoteControl/throttlePosition
Units: Ratio -1 to 1
Description: Throttle Position, -1<=ratio<=1, 1 is 100%

Shaft rpm is helpful for determining whether or not the gear box has engaged. An example is a master is coming into a wharf and goes to select astern, the throttlePosition shows that the lever has been moved to the astern position but shaft rpm is still showing a positive (or 0) value and astern gear has not been engaged.

What are everyone's thoughts