Question about hacker brushless
 

is there more than one version of the 7xl is a 7xl hacker the same as a B50 7xl......and are they much better than feigao 7xl?

yes, very high quality two pole motor... will rev like a mofo and stay cool compared to the feigao

From experience the B50 series of Hacker motors are better than the equivalent Feigao. However they are not as good as the C50 series of Hacker motors. The c50 have a segmented magnet, and run much cooler. They also appear to produce more torque/power than the B50. Depending on price the B50 is a great motor.

so this should be a good motor in a boat with a water jacket?

Yes.