Yes and no. Helpful aren't I.
For the most part, I see "brushed" motors and Ni-MH used in boats unless
you are talking about speed
the builders/modelers go to the "brushless" motors and to the Li-Po batteries (lighter, more power).
You can go to ebay and search for Traxxas motors and get 1000+ returns including brushed and brushless. I prefer brushed motors with 21 turns or more and 5 poles or more HOWEVER there are always exceptions. For instance, the motors used in the example Rich gave you are 12 turn motors (12T) and if you go to http://cgi.ebay.com/TRAXXAS-ESC-AND-...item3cb92f4694
you will find one plus the esc, an XL-5 waterproof esc, just like the two used in the larger boat. In the larger boat he used large props, 2" if I remember correctly, which is probably way too big.
The reason I look for higher motor turns is "current"; the lower motor turns (and also the size of the wire used on those turns), the higher the current draw and the shorter the runs for a given battery mAh (along with current comes heat, another possible problem). Low turns, higher RPM's, more power consumed; higher turns, lower RPM's, less power consumed. Plus, for the type of boat you're building, the prop can only spin so fast before you get into problems with "cavitation", and the only thing I know there is you're basically turning 'air' instead of water. Rich can probably tell you more than I can. Any way, higher RPM's also means more heat for the motor and the ESC, each of which can be water cooled, but why do that if everything is properly matched to begin with? As for prop size, I think the rule of thumb is 125% x diameter of the motor can is the MAX prop size, Rich or someone else can correct me if I'm wrong.
And yes, you should fuse the esc and the motor. for some information about motor, battery, esc hook-ups go to http://www.rcgroups.com/forums/showthread.php?t=783582
Got to get for now. Hope I havenn't messed you up.