I have not yet had a chance to remove the heat shrink but I think it looks like a metal plate heat sink that wont let me see the circuits.
I have extensively used in the past the proboat blue ESC and like them for one large Alfa since the drive is geared down so much that a faster starting ESC can be used,but ill probably will change it over any way.
But these blue ones do work very well as pump controllers in my hydraulic systems,as in the dive planes retracting system on the XXI .
Adjusted to pump just enogh water to operate the planes slowly and scale like ,without the need for adjusting valves or presure regulators.
If you havent tryed it ,get two syringes of medium size and fuel tubbing,a gear pump like the ones I posted or whatever and fill one with water and run the pump.
Instant mini hydraulic system made for a few bucks that can operate in the water! at least the rams can,adapt the rams to your doors,scopes diveplanes ectra and you have a very scale like operating sub without spending a fortune and easy to repair.
Great looking Oscar II by the way,I havent started on my Scale Ships one yet but the Typhoon is almost ready for sea trials.
Dave Amur Ship Yard