Hi,
The Wavemaster was designed by L J Rowell (Les Rowell) and marketed by HMM - Hammersmith Model Makers of Holland Park Ave. London. It was 34" by 11" with a 4" freeboard. I have a (brief) trade review dated July 1952, so it was available about that time. Retail price, in 1958, including purchase tax was 71/7 or £3.58. Ripmax advertised (in 1958) a suitable electric motor, the Kako 5 (34/11) or an E.D. Hunter 3.46cc diesel at 80/11. Not much difference in power there, then!