My FIL distributes oil in the USVI. Texaco Ursa 40wt and 15w-40 are the most popular down there. I was on the crew team in college and we practiced near a lot of barges and tugs. Their docks always had LOTS of texaco products on them, so it is not just a local choice, apparently. Now I work at the Philadelphia Navy Yard (what is left of it), and the tugs in service here use texaco products as well. FWIW.
JMH