As a Chief Engineer (four stripes like the captains) it depends on company policy and contracts. Most of the European companies will fly the four stripes at least in business and some do it for the Chief Mate and First Assistant Engineer (Second Engineer for English ranks) Business outbound to the ship. Most of the junior officers will get PE if available. My former UK/NL company had a policy for every kind of travel, including trains where all officers traveled in First where available, but bus was whatever there was. The Oil and Gas Majors go out of their way to keep their Senior Officers happy since there aren't that many of us and the assorted requirements to get all of the licenses and certificates is a long and expensive process to make the top tiers.

That's out in the commercial Oil and Gas part of the Merchant Marin (Navy). Once you get into the Container and Ro/Ro worlds things get a little bit less generous and when you get into the Bulk cargo and especially the Government worlds it's all going to be cattle class