Please provide a link to an example of such a system installed on a functioning marine diesel engine outside some inventor’s prototype shop. “Mostly” implies that such systems are routinely fitted to marine diesel generators. Please provide a citation to support that statement.
See above … If these mystical devices are fitted to generators, they are already operating at their “service speed” long before being connected to the bus, any generator that requires 30 to 60 seconds to respond to a load increase will no longer be online.
What you read on Google Patents is not necessarily what a marine engineer might find on a ship.
I think there is a great deal of smoke blowing around.