Hi,

Can you tell if the ESC is hot after it shuts down (hard to do if the boat is out on the water, I know...)?

If it's not overheating, it's possibly an manufacturers error, contact your supplier.

If it does get hot, it's possibly the long runtime from the 3000mAh that causes it.
Do you run full throttle when it happens, or do you run a lot half throttle (which will also heat up the ESC)?

Making the ESC the first watercooled object in your watercooling circuit is the next thing to do.

Regards, Jan.