Hi all I have a HDML at 1/24 scale. Its a nice size for the lake, but make sure that the stanchions, and fittings are robust enough for regular use. She does not need much power for a good turn of speed, I run each motor at 12v 0.75 amps, more than enough to stop quickly.
Twin ESC's allow the boat to rotate on her own axis. I used to have quite a heavy set of batteries, 4 A.hr nicads and these would give a whole afternoons running. They just wore out and I have not yet settled on the replacements(this is the 4th. set of batteries!) .
My one is diagonal planking 1/16th ply, in construction and pre-dates the Model Boats free plan issue, so must be about 20 years old now. Colour scheme is for the Mediterranean in blue and light grey, I have to say that I did not build her but bought her from a friends' estate, but I saw the building of her and spent a month restoring and getting her to work properly.
Good regatta boat and very handsome on the water.
good luck, Roy