We spent a lot of time this week servicing all the air conditioners and fixing some of our refrigeration systems. We also had the ship’s black water pumped out. The ship has around 14 Air conditioners. For most of them we just need to check them out and clean the filters. Unfortunately we had 8 that were getting cover in mold. The mold grows in the inside of the air conditioner unit and it can get pretty thick. This can actually put extra wear on the AC and cause it to run less efficiently. This mold can also have a negative impact on the air quality of the ship. Cleaning them can be a little tricky. We have to partially disassemble the AC to get to all the parts that need cleaning this process can take up to 2 hours per unit. So it took up alot of our time this week, but we got them all cleaned and checked out. 
Category: MATE Blog Archive Page 37 of 89
Posts that were imported from the historical MATE blog at marinetech.org
Great news, I finally went back to work! After 36 days of staying at home and reading I was itching to be working with my hands again. We’ve started dismantling Alvin. This week, the ET’s pulled off implodable volumes, which is anything that has air inside of it and has the potential to collapse with depth. These items are important; they are tracked by serial number and each one has a thick stack of paperwork to certify the depth they can go to. If one were to implode, there would be a pressure wave radiating outward that could damage the sub. Before we take anything off the sub, we have to find its location. Everything needs to be verified to check the weight balance of the sub. In the middle of the sphere is an x, y, z origin point; we measure from an item’s center of gravity to find its location. Once we have a location, I would take the item and measure the air and water weight. With those two measurements, the item’s volume can be calculated. After that everything gets cleaned up and put away. Throughout all of this, I’m recording all of the measurements and reporting them. It was busy work but it felt so good to be doing.
This week we worked on the ships two deck cranes. The ship has a port and starboard crane. We used them for loading and unloading equipment. We also used them to deploy different scientific equipment. The cranes are integrated to the ships hydraulic system. The system has two large pumps that continuously pump fluid through the system. When you would like to use one of the machines once the pumps are turned on you just need to open the valve for it. The cranes and pumps have been running really rough. We found the problem was air in the system. Because the system is constantly circulating we were able to just run the cranes for a while. Working them in all different directions till the air was all cleared out. We then cleaned and greased all the fittings, joints,and roles on both cranes. While we were doing our work, Don showed me how to operate the crane. It was really good to learn how they worked and I also got a lot of good practice running them.
This week I’ve been learning about how the Navy created standards for their equipment and kept calibration records. In 1973, the Electronic Test Equipment Classification Board was created in order to control what instruments were used and to eliminate unnecessary electronics. Equipment fits into two categories: general use, meaning the instrument can be used for multiple systems, and special use, which are used on only one system. With all the equipment being used, there needed to be a system to track what instruments are where and when they need to be calibrated. To do this, the Ship Configuration and Logistic Support Information System was created. In addition to tracking instruments, it also helps in listing documentation related to each instrument, training required to operate, and calibration schedules. Calibration is important so that the operator knows that the instrument is functioning correctly. When an instrument is calibrated, it is compared to a known standard. If what the instrument measures is outside of the allowed tolerance, it needs to be adjusted. Once an instrument is calibrated, it is important to ensure that it stays within limits. If a piece of equipment is exposed to heat, moisture, or dropped it may need to be recalibrated.
Some parts of Florida are beginning to re-opened even though there is still a threat from Covid-19, but Everything is still locked down on the University of Miami campus for now. Which has been good. I’m able to stay pretty isolated the way things are. My only contacts are Don the chief engineer and occasionally Denis the marine tech.
Don and I finished a few projects together this week. We replaced a coupling for our fire pump to its motor called a love joy. It turned into a tricky project because everything was seized up which made it very difficult to take apart. Then it was tricky to get back together because we had to line up the motor’s shaft perfectly with the pump’s shaft. It was pretty difficult to get it perfect but we managed to in the end. We had another tricky task we took on. We replaced the main aft door gasket which was difficult because it has to be glued in place perfectly, then needs to seal totally with no gaps around any of the edges. Once we finished that we went around and tested all the bilge alarms. We only had a problem with one getting stuck on but we were able to free it up. As I was looking closer at the alarm panel I noticed one of the voltage regulators had burt. It hadn’t affected our bilge alarm so we will test the smoke alarm system next and order a new regulator unit to replace the old one.
In continuing my reading of the NEETS modules, this week I learned more about alternating current. While direct current only flows in one direction, alternating current regularly switches directions. An AC circuit can be made by spinning a conductor, such as a loop of wire, in a magnetic field. This forms a generator. One way to determine the direction of current flow is to use the left hand rule: when holding your hand as shown in the example (taken from the NEETS module), your thumb will point in the direction of rotational motion, the index finger shows the direction of magnetic flux (movement from north to south), and the middle finger points in the direction of current flow. An easy way to remember the left hand rule is My Fine Clothes- Movement (thumb), Flux (index finger), Current (middle finger).
This week we worked more on testing and maintaining the emergency systems. The Captain is back home in North Carolina but he called and went over the whole alarm system with me over the phone. He showed me which each alarm was for so when i have time i’ll be able to go around and test them all. Then Don and I took out the gas power high pressure pump so we could inspect it. The other 3 emergence pumps are all electric. So the gas powered pump is very important. If we had a fire or the ship was taking on water and it knocked out the power on board, we would still have a pump to either fight the fire or pump out the incoming water. The pump ran well but it was due for its yearly maintenance. We changed the oil, gaped the spark plugs, replaced some cracked hoses, fixed the pull cord, and cleaned up any rust.
I love looking into the water from where we have been docked. On days when the water is really clear there is so much to see. I’ve seen Stingrays, Eaglerays, Parrotfish, Pufferfish, Atlantic Spadefish, Needlefish, Tarpon, Creole Wrasses, Snook and two Nurse Sharks. I’ve also gotten to see several Manatees. This week I had one swim right under the dock. I have been trying to learn more about the animals that live around Southern Florida.
This week I finished the NEETS module on direct current. One thing that I learned is that there are multiple formulas that can be used to calculate resistance in a parallel circuit. The first formula being Ohm’s Law (resistance is equal to voltage divided by current, R=V/I). This works to find the resistance, but if there is more than resistor one then you’ll need to find equivalent resistance instead. The reciprocal of equivalent resistance is equal to the addition of the resistor reciprocals (1/REQ = 1/R1 + 1/R2 + 1/R3 +…+ 1/Rn ). Another option if the circuit contains resistors that have the same value, you can calculate resistance by dividing the ohmic value of one of the resistors by the number of resistors (REQ = R/N). This is simple but only works when the resistors are equal.
Another thing I finally understand despite years and multiple explanations from previous professors (sorry Dr Moore), is voltage dividers. A voltage divider is used to provide different voltage levels to a circuit while only using one power source. A voltage divider consists of multiple resistors connected in series that step down the voltage. The way to calculate the value of the resistors needed is to use the 10% rule: the current used in the divider resistor should be approximately 10% of the load current. This is called the bleeder current and is not used in the circuit. Once the divider resistor is calculated, finding the total current and dividing by the voltage will give the ohmic value of the second resistor.
The crew is still on leave so it has been just Don the chief engineer and I working on the ship. It has been really quiet around here but we have been able to get a lot done. Our starboard generator was due for an oil change. I Have done multiple oil changes to marine engines in the past but each ship has different procedures to how they like to do each engine. So it was good to do it with Don to learn the best way to change the oil on this engine. We replaced both oil filters as well as changed the fuel filters. Once we finished we pumped 55 gallons of new oil to our ships oil holding tanks. Now that we have the time we might start going through and changing the oil on the other equipment as well. We have been doing alot of engineering work on this ship because our other operations have been suspended for now, but this has been good practice. Don has been taking his time to show me all the different systems on board. The last thing we did was go though the whole fier pump and bilge pump systems which have been very helpful. Don also lent me his two QMED study guide books and a stack of flashcards so I can start studying for the QMED. The QMED is the Coastguard engineering licence it stands for Qualified Member of the Engine Department. Studying these will help me a lot in having a better understanding of all the working on the ship, and it could also prepare me for the examination. I would like to take the test in the future.
This week I have been continuing to read from the Navy Electricity and Electronics Training Series (NEETS). This week I finished the chapter on batteries in which I learned about the parts of a cell, the different types of cells, and cells can be combined to form different types of batteries. I also started the chapter on direct current. So far I have read about Ohm’s Law, ways to calculate power and efficiency. Hopefully I’ll finish reading the module this week and move onto the next one.