47.30
Figure 8-6.—Typical steam ,turbine and reduction gear.
the direction of shaft rotation. It is frequently
necessary to operate an engine without having
power transmitted to the propeller. For this
reason, the drive mechanism of a ship or boat
must include a means of disconnecting the engine
from the propeller shaft. The devices used for this
purpose are called clutches.
The arrangement of the components depends
on the type and size of the installation. In some
small installations, the clutch, the reverse gear
and the reduction gear may be combined in a
single unit. In other installations, the clutch and
the reverse gear may be in one housing and the
reduction gear in a separate housing attached to
the reverse-gear housing.
In large engine installations, the clutch and the
reverse gear are sometimes combined and are
sometimes separate units. They are located
between the engine and a separate reduction gear,
8-5
