Examples of the use of the Load Diagram
In the following are some examples illustrating the
flexibility of the layout and load diagrams.
• Example 1 shows how to place the load diagram
for an engine without shaft generator coupled to
a fixed pitch propeller.
• Example 2 shows the same layout for an engine
with fixed pitch propeller (example 1), but with a
shaft generator.
• Example 3 is a special case of example 2, where
the specified MCR is placed near the top of the
layout diagram.
In this case the shaft generator is cut off,
and the GenSets used when the engine runs
at specified MCR. This makes it possible to
choose a smaller engine with a lower power out-
put, and with changed specified MCR.
• Example 4 shows diagrams for an engine
coupled to a controllable pitch propeller, with
or without a shaft generator, constant speed or
combinator curve operation.
For a specific project, the layout diagram for actu-
al project shown later in this chapter may be used
for construction of the actual load diagram.
Line 1: Propeller curve through SMCR point (M)
layout curve for engine
Line 2: Heavy propeller curve
fouled hull and heavy seas
Line 3: Speed limit
Line 3’: Extended speed limit, provided torsional vibration
conditions permit
Line 4: Torque/speed limit
Line 5: Mean effective pressure limit
Line 6: Increased light running propeller curve
clean hull and calm weather
layout curve for propeller
Line 7: Power limit for continuous running
178 60 79-9.1
Fig. 2.04.03: Extended load diagram for speed derated
engine with increased light running
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