The Z-4 cat below build by Mikael Frodé around 1976 was first designed for a 2 liter SAAB 4 cylinder inboard..
Well..on the back of the transom Mikeal installed a paddle wheel…!!!!!
The paddle wheel was very good but SAAB in Sweden could not deliver the 240 horses as promised..only around 110 hp..!!

A very disappointed Mikael took the SAAB engine out and replaced the very advanced/effective paddle wheel with a brand new 1977 Evinrude..2.4 liter V-6.. 200 hp outboard.

With the right power the cat was flying and Mikael scored his first overall win in the famous Roslagsloppet the same year..

Here is a picture and some reading in Swedish..

More about Micke Frodé here:..https://svera.se/blogg/offshore/micke-frodes-forsta-totalseger-i-roslagsloppet-var-1977/

Picture above by Marcus Weman.