They were quite popular in tugboats. I believe the RMAS dog class had Blackstone engines, as does Garnock at the Scottish Maritime Museum in Irvine. A dredger I once worked on had two (non-turbo versions) of these as generators.
@@SteamboatWilley GPS Marine, located in the river medway still operate a tugboat with a Blackstone mirlees engine as its main propulsion unit. absolutely beautiful example of what antiqauted tech can do.