Describe an engine suitable for a lifeboat. Describe the cycle of operation. How is it
reversed and what fuel does it use?
1. it should be a compression ignition engine
2. should be provided with enough fuel to run for 24 hrs
3. be capable of starting readily and reliably in cold weather and bad weather conditions
4. run properly under conditions of 10 degree trim and 10 degree list
5. it shall have self-priming circulating water pumps if engine is water cooled
6. If air cooled it should have the proper amount of air supplied to the position where it is
7. Adequate protection of engine and fuel tanks and accessories from bad weather
8. the engine casing should be of fire proof material
9. The engine should be able to be started remotely?
10. The engine should be using light weight materials
11. efficient ventilation of the engine
12. Fuel tank must be capable of withstanding 15 foot head water. It should have intake fitting
and relief arrangement and if steel constructed it should be galvanized externally.
Before starting the engine the oil level in the base should be checked. Fuel oil level should be
check. Then, levels should be maintained at all times. Turn-on the fuel and prime the fuel filter
with the fuel left on and lift the decompression lever to facilitate the turning of the engine. Turn
the engine with the starting handle and move the decompression lever back to the run position
and as the engine picks up speed, as the engine fires remove the turning handle. When the
engine starts. Slowly turns the control level back to run position and the engine is running. Some
lifeboat engines may be started by means of a 12 volt battery and starting motor system or a
hydraulic cranking system.
The engine is reversed with a gearbox which incorporates a cone type ahead clutch and a
reverse gear. It is not necessary to fit a thrust block. The gear box is capable of absorbing the
end thrust. The engine should always at idle when changing gears.
1) engine shaft running in one direction only
2) bevel wheel solid on engine shaft
3) propeller shaft
4) loose bevel wheel on propeller shaft
5) feather on propeller shaft (keyway)
7) free bevel wheel fixed to floor
In the ahead position the clutch dog (6) locks into the solid wheel (2) of the engine drive shaft
(1) and by means of the feather (5) both shafts (1) and (3) turns in the same direction while
wheels (4) and (7) running idle. in the astern position the clutch (6) is moved by means of the
lever of the reversing gear by a yoke the clutch dog (6) now locks in the loose bevel wheel (4)
and the drive is moved from the freewheel with ( ) propeller shaft (3) and revolves in the reverse
position direction of the engine shaft, the feather (5) again acts as the drive.
Another method of reversing is the reversible propeller blades of which can be rotated to any
angle by movement of suitable gear contained in the hollow boss and actuated by a lever and
rod, the rod passing through the hallow tail shaft.