I finally made my way to the end of this thread. I bought a Shockwave on ebay from a hobby shop that listed it for "parts" because the shaft was locked up and they didn't know if it was the motor or shaft. I wanted something to get used to racing boats, as all my previous efforts have been scale/semi-scale, and the boat seemed to have most of the equipment I would eventually need in a sport scale hydro. (That's what I thought at the time; now I have a completely different hardware package for the sport hydro.)

Turned out the motor was the culprit, but in trying to figure that out, the hobby shop had stripped out the lock screw on the shaft end of the connector (it is a 1/16" socket, not a 1.5 mm like the one on the universal). (This seems to be a common experience, based on this forum.) Once I got the connector removed, I took out the motor and there are loose parts inside and it locks up -- probably a broken brush. The motor does not come apart easily, like the "rebuildable" car motors, so I decided to replace it.

I had bought a 13 turn Venom Fireball modified motor on ebay, so I installed that with the stock water cooling and a 3000 mah NIMH 6 cell battery. First time I ran it, it went into thermal cut-off after a short time. I messed with motor alignment and it ran a little better but the esc was still very hot, the motor not so bad. I figured perhaps the stock prop is too big for the higher rpm motor and it is drawing too much current instead of operating at top efficiency.

Then I was reading up on the Venom on the car threads, and the comments were "not so nice," and I found a Trinity Chameleon 2 19 turn Pro with a sticker on it that shows a top speed of 31,086 rpm for a good price. THe comments on the Chameleon were all very good and the rpm rating of the Chameleon is only slightly below that of the Venom, even thopugh it is a 19 turn versus 13 turn motor. I was also told the higher turn motor would have more torque than the 13 turn, so I figured maybe it could handle the stock prop. I had also bought a 50 amp esc which looks nearly identical to the stock Pro Boat ESC, which I figured I could use for scale.

The Chameleon did seem to run the boat faster, but I never got top speed because the esc would cut out momentarily at full throttle -- not to a complete stop, but like a car motor "missing." As it turns out, the Chameleon didn't have suppression capacitors installed, so that explains the "glitching." And the ESC, though never thermaling, was too hot for the finger test, but not hot enough to cause a drop of water to "sizzle." The motor body was good but brush tabs hot.

So here comes my question. It is my understanding that the stock prop is probably still too large, but I read on this forum it is only 35mm, which seems pretty small, and on here everyone is talking about using a LARGER prop to increase performance. Adding cells would only increase the current flow and the heating, wouldn't it?

I do plan to add cooling tubes to the brush tabs to hook into the water cooling loop, and perhaps even some tubing on the esc heat sink. But it still seems to me if the motor is "over propped" just like in R/C planes, it will decrease run time and not get the best performance from the motor/prop combination.

So what IS the best size prop for this boat?

My other alternative is to put in the sport hydro set up -- a MambaMax 5700 brushless with a Castle Creations Barracuda 80 esc.

PeeJay