Marine Installation Manual
2021-08
2-15
2 Engine Power and Speed
2.7 Prohibited operation area
X72DF
Prohibited operation area for different speed rated engines
As the prohibited operation area of the engine is between 70 % and 100% of the
R1
—
R2 speed, the prohibited area is smaller when the speed rating of the engine
is lowered.
Figure 2
-
8 Calculating the prohibited operation area for the CMCR speed
shows an engine with a CMCR speed which is rated at 85 % of the
R1
—
R2 speed and therefore is only affected by a portion of the prohibited area
of the R1
—
R2 speed range. The final graph for a CMCR at this speed is shown
SM-0523
11
12
E
F
40
50
60
70
80
90
100
40
30
20
10
0
5
7
8
Field A
Prohibited
operation area
Engine speed
Engine power [% Rx]
[% R1 - R2]
[% CMCR]
50
60
70
80
90
100