I am using two sets of 14 2500 NMH cells to power two Astro Flight Marine 25s in my Dumas 48 inch PT boats. The heaviest boat weighs 23 pounds. I get 12 minute runs going at ¾ throttle. You should be able to get much longer runs with higher capacity battery cells and lower throttle settings. Check my build thread for some ideas. Dan.
http://www.rcuniverse.com/forum/rc-s...l#post11009591