They need lots of water to Cool them down.Longer your cooling lines are the harder it is for the water to the esc and motors.I use Xtra large lines and I use prop thrust pickups. 6s temps dont exceed 110 degrees f. I dont trust the rudder and under the hull pickups learned that years ago.
The ESC is crap. My 4S Lipo smoked out, but the ESC normally can take 6 S. Cheap ESC´s cannot be so good as the expensive One´s. Marine ESC´s i used only from Dynamite or Hobbywing, thats the best Choice
bulshit,his set up was not good,look at the calculation of tec and games.this is its failure,not the brand.hobbywing,to expencif,if you lost your boat you screwed,in this case,4 or 500 dollars if you used hobbywing set up,and it smoke also
your motor give max 3500W your battery it is 4s 14,8v so 3500W/14.8v=236A!!! You ESC it is 150A !!! The failure it is your my friend. It does not seem that you have correctly fitted the cooling pipes to ESC.
