Report:
SO it turns out... (no pun intended) that a craft like the one pictured above DOES NOT constitute a good starting platform for scaling power. Steering is unmanageable as the vehicle just wants to vector to whatever position you aim the prop instead of arching like you would expect with rear steering. Obviously... its due to the flat bottom.. which is required for the 6" deep passages that we were exploring.
The steering issue does not pop up at all with any of my vessels which have a Vbottom or Vbow... yep... makes sense. Its a keel or rudder of sorts.
So - to make a super low draft vehicle work with high power attention will have to be paid to keeping a straight edge in the water. I am sure every boating enthusiast in the world knows this... but I am a land and air animal with limited experience in experimental water craft.
We finally blew up the motor above.
Failure mode was fishing line wrapped up in the prop causing an over-current.
Had to push the vehicle 1 mile back to port.
Was running 4S 90Ah Thundersag cells on a motor that was designed for 12V lead acid and had seen 24V lead acid in the field.
24V on the stock switch blew out the mid-power channels due to over-current.
Oddly enough... moments before the entire system failed... the granularity of the speed controller returned!
Disassembling today - expect to find reflowed solder, burnt resistors and coils, etc.
Do not anticipate burnt coils in the motor as I believe it is the same spec motor as found in the 24V option and prop sizing controls speed and thrust.
Until next time... Eat your Broccoli and dont take antacids from strangers.
-methods