I'm presuming a single self priming pump will suffice, can I ask have you seen any lately worthy ones and what are they running off of a separate power source ?
And I agree 100% with andy, the water flow is cold coming in and at the end it exits the boat so should never get really warm, I know loads about computers I build them as a hobby and my fully water cooled PC worth over £5000 is as cool as a cucumber well until all this ruddy heat and humidity of late.
Andy not only is your boat very clean but the inside is huge lol what is it If I may ask and also can I ask how are they heat levels in the boat with them motors and ESC's and one last question in 2 parts...
1. What type of battery setup are you running size wise
2. What sort of run times are you getting, sorry to ask these questions but its been a little daunting moving from brushed old school no offence to anyone to the newer brushless and lipo setup