Ironically, these solutions would be perfect for boating use, if only they used a diesel engine instead. Regular ICE will not go away anytime soon in marine world and I don't think they see the sales potential here if they developed their powertrains with that usage in mind as well.
Aren't boats typically highly geared direct drive? Hybrid only really benefits when you have lots of changes in speed or are using it for torque conversion as in diesel-electric trains.