Hi Slash,
If the outlet is ornamental, put it where you see it on most 1:1 boats either in the side, or the stern.
If you have a working watercooling for motor and ESC, I'd keep the tubes as short as possible to reduce drag. So inlet (presumably behind the prop), ESC, motor and the shortest way overboard.
If you want to have a cooling system that will work even when crawling along, or going in reverse, use a pressureless system: the inlet in the bottom, slanted forward (behind the prop, if there's room for it) sanded flush with the hull and the outlet in the bottom slanted towards the stern.This creates sucktion, which helps maintaining flow, even at very low speed, once the system has been filled with water, with a small burst of throttle.
The pictures are from my 110 cm M.A.S., which is a stepped hull, so the in- and outlet are in the trailing edge of the first step, to assure waterflow at all times. In a non stepped hull like the Diva they should be located towards the rear.
The inlet needs a bend in the aluminum tube, hence my remark on the need for space to house it behind the prop. If there is no room, next to the rudder will work just as well.
Don't be tempted to route the tubing up, keep it as low as possible to avoid the 'uphill struggle' of the water filling the system, once it is filled, the height is of no consequence anymore.
Regards, Jan.
