Volvo D11 series, Installation Manual

Page: 36 / 212

General arrangement and planning
34
Single and twin installations
The most effective method of propulsion is generally
achieved with a single installation. If more power is
required than is possible with a single installation,
two engines, each with a separate propeller shaft can
be fitted.
Improved manoeuvring is gained in two engine instal-
lations and separate propellers as the power output
can be controlled separately and independently for
each engine. One engine can be run reverse and the
other ahead when for example manoeuvring at low
speed.
Two or more engines coupled to a common transmis-
sion and one propeller is a third possibility.
∅
E
B
A
D
F
A
B
C
D
E
Ensure that there is sufficient space between the
propeller, hull, keel, skeg and the rudder. It should
be possible to move the propeller shaft at least 200
mm (8") aft to allow the removal of the reverse gear
or coupling. Also make sure that any transverse bulk-
head does not impede its removal. Sufficient clear-
ance, approx. x the shaft diameter, must be pro-
vided between the propeller and the stern bearing to
prevent the propeller from pressing against the stern
bearing. Allowance should also be made for rope cut-
ters if they are to be fitted. See figures on this page,
position (
E).
The minimum distances to the hull, keel, skeg
and rudder.
∅
= Propeller diameter
A = 0.0 x
∅
B = 0.5 x
∅
C = 0.0 x
∅
D = 0.08 x
∅
E = Approx. x shaft diameter
F = Shaft angle. Shaft angles exceeding 2° should
be avoided.
Example: The measurement (A) for a boat with a
propeller diameter 30" (762 mm) is 0.0 x 762 = 76
mm (0.0 x 30" = 3") minimum.
The measurement (
A) must never be less than 50
mm (2"). For classification, the requirements of the
respective classification body must be followed.