In the 1960's Victory industries made 2 different boats as I remember, the "Vosper RAF crash tender", which I had, and the "turbo yacht" which featured three(!) propellers.
The crash tender was beautifully made, with real brass fittings, propellers and rudders initially, before they started making them out of plastic. The on off switch was a rotating lifebouy! They drove the two (or three) props off 1 motor connected via an elastic belt which was the Achilles heel of the design as I remember, because when it broke you could really struggle to find a substitute elastic band that would work without breaking or falling off (usually in the middle of the pond..)