More info for you. Thank you
Unfortunately, it is not allowing me to upload pics yet, but here is a little more info.
The boat is a Syma Century
my transmitter is an Austar AX5S 3 channel
the motors are racestar 2435 4800kv brushless
the props are 3 blade rounded and just about 30mm diameter.
I believe it is surface drive. The shafts come out at the back of the boat on both sides of the rudder.