By Theresa Williams
Slackjaw Sally here with more life-aboard-ship news! I interviewed the Chief Engineer Steve to find out what it takes to keep the ship going and comfortable for the people aboard. Steve thinks of engineering on the ship in three parts: the hotel, the propulsion and the science.
Hotel: Water is the most important consideration for making the ship livable for humans. Fresh water is made in two ways on the ship. One way is by evaporation and condensation. Waste heat from the engines is used to boil clean salt water in a vacuum, collecting the steam and condensing it to form pure salt-free water. Another way is to push salt water through a membrane using a high-pressure pump. The salt stays on one side of the membrane and fresh water comes through the other. This is called reverse osmosis. The evaporator and reverse osmosis units need to have their strainers and heat exchangers cleaned regularly to keep them running efficiently.
The “Wahta Maka” (New England accent) makes between 3,000 and 5,000 gallons of water per day. A large group like us uses about 3,000 gallons per day. The ship has 2 tanks that can hold 12,000 gallons of fresh water as a reserve. (As an ocean fish, I personally prefer saltwater.)
Waste water is handled by the Crapper Zapper, aka MSD. It is drained to a tank where it is sterilized using chlorine that was produced by passing an electrical current through sea water. The sterilized waste water is pumped over the side. Solid waste is carefully sorted. Food waste is dumped over the side when the ship is more than 25 miles from shore and the fish like me really appreciate the extra snacks. All oil waste, bottles, cans and cardboard are recycled. Paper and plastic waste is burned in the ship’s incinerator.
After water, the next big issue for human comfort is air quality. The heating, ventilation and air conditioning (HVAC) system is a series of fans which move air into, around and out of the ship. Outside air is pulled into the ship, heated if necessary for temperature and humidity control and then cooled by blowing it through a chiller. The chiller is a heat exchanger that moves the water over chill water that was cooled by the 110-ton air conditioning units. Cooled air is circulated throughout the ship. Exhaust fans discharge air from the ship, mostly from the “Heads” or bathrooms. Living in the ocean is much simpler, the temperature is always just right for me!
People on the ship also need electricity to make life comfortable and to do their work. Electricity is produced by moving a conductive wire across a magnetic field. The electric power aboard is produced using 6 electric generators turned at 1800 rpm by Caterpillar diesel engines.
Propulsion: Electricity from the generators also powers Atlantis’s propellers and thrusters. The ship can carry 250,000 gallons of diesel fuel to get it through long journeys. The Atlantis is very maneuverable. It can maintain a dynamic position (DP) of 10 feet or less in fairly rough seas. The ship can turn around within its own length and go from full ahead to full astern in seconds (Not something we do a lot, btw). Propulsion equipment requires regular maintenance including changing and cleaning filters and changing out the oil. The picture below shows the top gear box of a stern thruster. Its DC Motor is in front and the propeller is below. It’s like an outboard motor that can turn 360 degrees continuously in either direction.
Science: Steve and his engineering crew keep the engine room running as efficiently as possible so the science team can collect samples and data without any distractions.
Steve enjoys the work he does and the opportunity to help make the world’s environment better understood.
Wow! The Chief Engineer has a lot to manage to keep the ship running and its inhabitants comfortable. I hope you learned as much as I did!
I’m off to a relaxing float break,