NOAA Teacher at Sea
Aboard NOAA Ship Okeanos Explorer
May 30 – June 13, 2019
Geographic Area of Cruise: U.S. Southeastern Continental Margin, Blake Plateau
Date: June 1, 2019
Latitude: 28°19.3’ N
Wave Height: 1-2 feet
Wind Speed: 11 knots
Wind Direction: 195
Visibility: 10 nautical miles
Air Temperature: 28°C
Barometric Pressure: 1012.5
Making the Engines Run
Engines on this ship are run with marine grade diesel. Before the diesel can be put through the engine it must be cleaned of any impurities. A centrifuge system is used to spin the diesel at a very fast pace in a circle. As the diesel spins any impurities are flung out leaving behind the purified fuel. If the fuel is not purified before it is put through the engines, they will gunk up and not function properly. NOAA Okeanos Explorer has 4 engines. Currently we are running 3 of them and the fourth one is the backup. There is also a fifth generator that can serve as a backup if needed. There are roughly 180,000 gallons of diesel on the ship and roughly 2,200 gallons of fuel are used per day. In order to make the engine work, air in the engine is compressed causing the air to heat up. Then you spray fuel into the compressed air and the heat of their air causes an explosion leading to the process of combustion. In order to determine if complete combustion is occurring and the engine fuel is clean of impurities you look at the exhaust. If the exhaust is clear it means you are seeing full combustion and the fuel is clean. If the exhaust is not clean, black for example, it means that combustion is not complete or the fuel is dirty.
Cooling the Engines
The engines must run at a temperature below 200°F. When these engines run they create heat so to keep them at a temperature under 200°F you need to cool them off using a heat exchanger. A heat exchanger is a series of pipes that run hot substances past cooler substances. These substances do not come into contact with one another, but are piped past one another. The heat transfers to the cooler substance through the series of pipes thus cooling the previously hot substance. On this ship, oil is used to lubricate the pistons on the engine, but it also serves a coolant. The oil is then cooled via freshwater called jacket water and the freshwater is cooled via seawater taken from the ocean. The ocean surface water is 74°F when it enters the ship and leaves the ship at roughly 84°F.
However where does this heat go? The first law of thermodynamics, The Law of Conservation of Energy, tells us that energy cannot be created or destroyed, only transferred or converted. So why not convert this heat energy into some of use? Well guess what. The engineers on Okeanos Explorer do just that. Some of the heat goes into the seawater used to cool the jacket water and some of the heat is used in the desalination system.
Remember we left off with desalination in the previous blog. They use the heat coming off the engines to heat the saltwater, evaporate it, and retrieve the freshwater. However, if you remember these engines must run below 200°F and in order to boil water you must be at a temperature of 212°F. I know many of you are probably thinking salt in water actually lowers the boiling point, but really the opposite is true. Salt actually increases the temperature needed to boil water. However, it is minimal so it won’t affect your pasta too much. Feel free to add that pinch of salt like a true chef.
In order to boil water with 200°F of temperature or less we need to change the pressure of the system. This is done through a vacuum that decreases the pressure in the system allowing water to boil at a lower temperature. It is similar to when you go hiking in the mountains (less pressure than when you are at sea level) and go to boil water. It boils quicker because less heat is needed since the pressure is lower. So by changing the pressure in the system to one that would be seen at a higher altitude, engineers are able to use the heat from the engines to boil the salt water on the ship, allowing us to have access to freshwater for drinking, bathing, and cooking purposes. Pretty ingenious right?
Now hopefully you were paying attention in the first paragraph when I talked about how much fuel is on board and how much is used each day. As fuel is used, the weight on the ship will change affecting stability. A ship with weight is more stable in the water than a ship will little to no weight. Therefore as fuel weight is lost it must be replaced. One gallon of diesel weighs approximately 7 pounds. So if we are using 2200 gallons a day we are losing 15,400 pounds of weight. How do the engineers accomplish the task of adding more weight? What is all around us weighing 8.6 pounds per gallon??? Seawater! Yes! So ballast tanks are filled with seawater to add weight to the ship that is removed when fuel is used.
Ballast water is taken in through a filtration system before it even reaches its holding tanks (separate than the fuel tanks). The water first passes through a filter to remove large particles (such as larger pieces of plant material or debris) and then passes through a UV system that will kill any organisms. When the ballast water is released from their holding tanks in order to allow more fuel to come on board, the water must pass through the UV system once more to make sure nothing alive (plants, animals, bacteria, etc.) is getting into the water.
This purification of ballast water occurs to prevent invasive species from entering new areas. An invasive species is a plant or animal that is from somewhere else and is introduced through human actions. When these species establish in a new area and begin to outcompete native species, affect human health, and become costly to remove, they are classified as invasive.
Where I live on Lake Erie several species such as zebra and quagga mussels, round goby, and spiny water flea have all been introduced from ballast water from ships coming from the inland lakes of Eurasia. These ships would need to dump their water when they entered the shallower river ports of the Great Lakes, spurring a silent invasion. All four species are negatively affecting native populations of important species and are costly to manage. Then same is happening along the East Coast with species such as European green crab.
I would like each of you reading this blog to learn more about a species introduced to U.S. waters, whether they be fresh or salt, through ballast water. Feel free to let me know which organism you chose to learn more about in the comments section of the blog.
Today was a really special day at sea. It was my 30th birthday. I could not have imagined a more amazing place to turn 30. I spent the day learning all about the engine systems on board, out on the bow enjoying the breeze and sunshine while looking for ocean critters, and was treated to the sweetest cake ever. It was so kind of the chefs on board to make me a cake for my birthday. It was a red velvet cake (my favorite) with chocolate frosting and decorated with chocolate pieces and white icing. We had it with some chocolate raspberry swirl ice cream. Truly a wonderful celebration with my new friends.
I spent the hour before sunset enjoying a nice yoga and meditation session before the most amazing sunset we have seen at sea yet. The clouds and sun put on the most spectacular display of color. Afterwards I learned more about the happenings of the mission control room (basically the mapping hub for the ship). I learned how we launch equipment to collect water column data and how we clean the data removing noise. I will be writing a blog on the mapping mission soon.
After our shift ended, my roommate and I ventured to the bridge to learn about piloting a vessel at night. We learned what equipment they rely on and how they manage their night vision. And then the most spectacular part of the whole night! The stars! Wow! It looks like someone through glitter (plastic free glitter preferably) into the sky. I have never seen so many stars in my life. We saw the Milky Way, Big Dipper, Little Dipper, North Star, Jupiter and so many other constellations. It was a wonderful end to a great birthday day.
Did You Know?
Even numbered locations (such as muster stations or staterooms) on ships are located on the port (left) side of the ship and odd numbered locations are located on the (starboard) right side of the ship.
Different ways to measure are used at sea. You can see some measurement conversions below.
1 nautical mile = 1.151 statute mile
1 knot = 1 nautical mile per hour = 1.151 statute mile per hour
1° Celsius = 33.8 °F
Animals Seen Today