Marine Engineering, Propulsion and Vessel Systems
Marine engineering and vessel systems checks that you understand your propulsion plant well enough to run it, spot faults early and keep the vessel moving safely.
Propulsion and systems
- The main engine is usually a medium-speed diesel; heat goes to a closed freshwater circuit cooled by a heat exchanger or keel cooler. A blocked raw-water intake or worn impeller shows first as rising temperature.
- Fuel runs from storage tanks through a separator and filters to a day tank. Water and dirt are the commonest cause of sudden stoppage; drain and check daily.
- Transmission: reduction gear, shaft, stern-tube seal, propeller and rudder. Watch gland drip, vibration and abnormal noise.
- Bilge system: independent pumps, high-level alarms, oily-water separator. Never pump bilge water overboard.
- Wheelhouse control: remote engine control and alarms for oil pressure, coolant temperature and bilge level; a second independent means of steering and emergency controls.
Worked example
Engine 180 kW, specific consumption 210 g/kWh, fuel density 0.84 kg/L, usable tank volume 2,700 L, service speed 12 km/h. Consumption = 180 × 210 = 37.8 kg/h ÷ 0.84 = 45 L/h. Endurance = 2,700 ÷ 45 = 60 h = 720 km; with a 20 % reserve about 576 km. That reserve is what saves you when the next bunker station is closed.
Pre-departure checks
Engine oil and coolant, belt tension, bilges dry, day tank full, batteries charging, alarms tested, steering tested both sides, bow thruster tested, exhaust clear.
Traps
Running the day tank empty; ignoring a slowly rising temperature; assuming the second steering pump works without testing it; a dirty separator filter that only shows up at full load.