ORIGINAL: bigwaveohs

I am planning to run the same X-Power 100A ESC with the Aquacraft UL-1 motor and 5000mAh, 30C, 4S1P Lipos on a tunnel hull w/42x55 2-blade prop. Is this OK for this ESC?
[/quote]
Hi bigwaveohs,

For all ESC's in this price segment goes the same: check if the fets are in one plane and physically touch the heatsink (usually it's only 30% that do touch the heatsink, anything over half the load will make it burn up due to lack of cooling).
While you're at it, use the cooling medium that's available in a boat and add a watercooler!

Prepared that way it will power your set-up without overheating.

Regards, Jan.