C or Sea?

I refer to your article “New Ship Explores Seas Under Flag of Ecology” by Shirley Slater and Harry Basch (Nov. 18). It states: “The ship uses only marine-diesel or gas-oil, cleaner fuels than the heavy-duty bunker or sea oil that most ships use.”

I’ve been involved with oceangoing ships most of my life and in oil for 15 years of my life, but I’ve never heard of “sea oil.” How about Bunker C oil, which many ships use? PETER HUME El Toro