There are many questions asked about the “best engine” for a particular boat. This page will provide some links to possible answers:

Electric propulsion

Electric propulsion is becoming more popular, and the affordability of our catamarans seems to encourage experimentation. See this twin electric 9m

Outboards

Twin outboards: Many people have added twin outboards in various configurations: From attempts to make an 8m plane:…to smaller (9hp) mounted just in the hulls and retractable

Summary of consumption data for Yamaha T9.9 with a 11 3/4“ x 7” prop on a 3000lb 20ft monohull (from the external link.(click image to enlarge))