Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
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66 Proceedings Fall 2014 www.uscg.mil/proceedings A nswers Engineering 1. Note: Fuses and circuit breakers are devices used for circuit protection. When a fuse is placed in series with a circuit breaker, each device offers a different type of protection that complements the other. The thermal trip-type circuit breaker, acts like a time delay fuse, and will protect a circuit against a small overload that continues for a long time. A magnetic circuit breaker acts like a single element fuse, and will trip instantly when the preset current is reached. A. time delay protection Incorrect answer. A time delay fuse would be appropriate to use with a magnetic trip-type circuit breaker. B. short-circuit protection Correct answer. A single element fuse provides short-circuit protection and would be appropriate to use with a thermal trip-type circuit breaker. C. short duration surge protection Incorrect answer. A time delay fuse provides short duration surge protection and would be appropriate to use with a magnetic trip-type circuit breaker. D. sustained overload protection Incorrect answer. A time delay fuse provides sustained overload protection and would be appropriate to use with a magnetic trip-type circuit breaker. 2. A. Type I Incorrect answer. A type I MSD is one that through treatment of the sewage produces an effuent (pumped overboard) having a fecal coliform bacteria count not greater than 1,000 per 100 milliliters and visible foating solids. B. Type II Incorrect answer. A type II MSD is one that through treatment of the sewage produces an effuent (pumped overboard) having a fecal coliform bacteria count not greater than 200 per 100 milliliters and suspended solids not greater than 150 milligrams per liter. C. Type III Correct answer. A type III MSD is one that is designed to prevent the overboard discharge of treated or untreated sewage or waste derived from sewage. This type of device requires the storage of all sewage and waste onboard. D. Type IV Incorrect answer. A type IV MSD does not exist. 3. Note: On a four-stroke engine all the combustion cycle events for all cylinders takes place in two complete crankshaft revolutions or 720 °. On an eight cylinder engine, the interval between fring events is 90 °. A. the exhaust stroke Incorrect answer. #4 piston is on the exhaust stroke. B. bottom dead center Incorrect answer. #2 and #7 pistons are at bottom dead center. C. the intake stroke Correct answer. #6 piston is on the intake stroke. D. the compression stroke Incorrect answer. #5 piston is on the compression stroke. 4. Note: When determining the highest temperature to which a fuel oil may be heated, the pressure on the fuel and exposure to oxygen must be taken into account. A. for atomizing Incorrect answer. The fuel oil is under pressure and not exposed to oxygen in the fuel supply header prior to reaching the atomizers. The fuel oil is routinely heated above the fash point to attain proper viscosity for atomization. B. for centrifuging Incorrect answer. The fuel oil is under pressure and not exposed to oxygen in the fuel line to the centrifuge and within the centrifuge itself. The fuel is routinely heated above the fash point for centrifuging. C. in a storage tank Correct answer. The storage tank is vented to the atmosphere and the fuel oil is exposed to oxy- gen. For safety reasons, the fuel oil must be maintained under the fash point. D. in the recircula- tion line Incorrect answer. The fuel oil is under pressure and not exposed to oxygen in the recirculation line. The temperature of the fuel oil in the recirculation line is a function of the fuel supply temperature.