Love to see this in a marine application for repower option

[Carpediem44DB]

Opposed piston engine
Here’s Why We Don’t Have Opposed-Piston Engines—at Least Not Yet (msn.com)
Carpe Diem

 

[Todd320]

Here is a similar article about a new rotary. Lighter, fewer moving parts, so less maintenance, more fuel efficient, and way smaller at same horsepower. https://www.liquidpiston.com/invest, supposedly can scale from 1hp to 1000.

 

[hughespat57]

How about three bank delta config, all opposed diesel...
https://en.wikipedia.org/wiki/United_States_Nasty-class_patrol_boat
https://everythingaboutboats.org/napier-deltic/