A lot of discussions about shaft generators on the forum lately, especially if shaft generators could be fitted on ships with low speed diesels and fixed pitch propellers.
Yes they can and are:
https://trid.trb.org/View/74521
MAN Energy Solutions have their solution:
Ships with low speed 2-strok engines and fixed pitch propellers fitted with shaft generators can even be used to boost propulsion power, or while idling/slow steaming (common on older OSVs):
If the shaft generator is of the Permanent Magnet (PM) type it can even be used while manoeuvring in port:
Kongsberg’s hybrid shaft generator system: