Hi Barney

Normally the ESCgets the cold water first, which then goes to the motor - the ESCelectronics are more sensitive to heat. Looking at your other post I see you also have a water-cooled motor mount - the orange plate the motor is fitted to.Therefore the pipes should be:

- water pickup to ESC (cool the electronics 1st)
- ESCto motor jacket (take most of the heat out of the motor next)
- motor jacket to motor mount (take bit more heat away from the motor)
- motor mount to water outlet (get rid of the warm water)

In terms of measuring props there are two key dimensions: diameter and pitch.

- diameter can be measured easily with a ruler (or at least estimated within a mm) across the blades - at the back of the prop is usually easiest.
- pitch is a theoretical measure of how steep the blades are angled - how far forward the propellor (boat) will move in one revolution if there were no slippage against the water. Pitch is like gears in a transmission - lower pitch =lower gear, good for acceleration but lower top speed; higher pitch = higher gear, better for top speed but worse for acceleration. Typical boat ranges are 1.4 to 1.6 for the type of prop you have.
- pitch can't practically be measured at home, but you can get an estimate by comparing the length of the propellor hub (the tube the blades are attached to) with other props of known pitch. The shorter this tube, the shallower the blades and the lower the pitch; the longer the tube the higher the pitch. Therefore if you took your random prop to a store and compared it with other props of the same diameter, the prop with the hub closest in length should be closest in pitch.

-yellow-bird