I would really like diesel-electric hybrid systems to work for sailboats, but simple diesel inboard motors currently will be more efficient and reliable for propulsion.
If your desired use involves on board equipment that has a large electric demand, then production of electric for that demand has priority and propulsion is secondary. An electric propulsion system may then be the smart choice.
Search for Nigel Calder articles in Sail magazine for research on hybrid systems.
1970 Havsfidra 20 by Fisksatra
On the Delaware River at Fox Grove Marina Essington PA