A Photo & Discussion Forum for Wharram Design Enthusiasts
It's all possible , I guess but if you want to go that way yo might as well consider a ready made catamaran drive like Sonic Sillette. They come with or without a gear box ,such as you prefer.
Re the small 1 liter car engine : you still need to marinize it ( water cooled exhaust , impeller pump, heat exchanger etc .Problem with car engines is that they often have an enormous oil sump which is difficult to tuck in the confined space of an engine box and which usually also very susceptible to corrosion .
Also I'm not so sure about a "one liter "diesel engine" being adequate. On a T30 or smaller any diesel installation is way too heavy .With a T 38 or bigger a diesel is a consideration worth making .Our T 38's are driven by a single Kubota VE 1200 ( 1235 cc) which gives about 24-26 HP . In our case they drive a twin propeller hydraulic system. In flat water we get 6- 61/2 kts out of them at cruising (2400 ) rpm. So adequate but certainly not overpowered .
Siam Sailing, Phuket