Each of the two oil rigs that are being outfitted on the Portland waterfront will have a crew of 115.

A 4,400-horsepower diesel engine allows the rigs to propel themselves around the world while exploring for oil. Six smaller diesel engines make electricity. Together, they could power a city of 18,000 people.

Each rig’s twin pontoons are 250 feet long and contain compartments to hold 518,000 gallons of diesel fuel and 105,000 gallons of drinking water. The pontoon columns hold desalinization and sewage treatment plants.

Most of the workers will live and work on C deck. Typically two crew members are assigned to a small interior room, each with its own bathroom and shower unit. Crew members spend 30 days at a time on the rigs.

Above them, D deck contains quarters for officers, who get a single room with a view, plus their own bathroom. A small hospital is there, as well. But most of this deck is exposed and open, and it is outfitted with lifeboat stations.

On the top, the drill deck holds more senior officer quarters and a 66-by-66-foot helipad, the rig’s lifeline to the outside world. The drill bit hangs above a giant hole in the middle of the drill deck.

Far below, on B deck, steel racks line the walls and ceilings and carry cables through the rig. Three “mud pumps,” each the size of a dump truck, move clay slurry to lubricate the drill bit.