I built one of these over the winter. The plans call for a Dumas 6 volt motor (model 2004) set up in a direct drive configuration. It is my understanding that this motor is a bit pricey. I used a Graupner Speed 400 coupled to a 3:1 gearbox, which aligned nicely with the prop shaft. This motor happened to be one I had collecting dust in my shop, but I have seen them (or their generic equivelants) dirt cheap at model shows. I'm turning a Raboesch 40mm 6 bladed prop, and the performance is excellent. The 2 blade prop from the kit worked similarly.
The battery compartment measures approximately 6.5 x 2 x 1.5 inches. I was able to just barely able to squeeze in a 6 pack of sub C's arranged in two parallel sticks of 3 cells each. I recommend NiMH over regular NiCad's as they are lighter and have a higher capacity. I'm using 4000 mAh cells in mine. I had over 2 hours running time when I ran this boat at the SubRegatta last month. You could also do what Dave Welch did, leaving the battery box out entirely and installing a sealed gell cell in the wet area. Good luck with your kit.
Edited By Crazy Ivan on 1061820451
George "Crazy Ivan" Protchenko
“There are the assassins, the dealers in death; I am the Avenger!”-Nemo
"I'm disinclined to acquiesce to your request; means No!"-Capt.Barbossa