Simrad AP14 Manual page 7

4 Installation - AP14H
Section 4 covers the installation of the AP14H
Hydraulic version. Please refer to section 5
for AP14R Rotary version installation instruc-
tions.
4.1 Pump Installation
The AP14H links a reversing pump into the exist-
ing hydraulic steering system on the boat using T-
fittings. The pump reproduces the effect caused
by turning the helm, so the pilot can steer the boat
without attaching any device directly to the helm.
Confirm that the volume of the cylinder of the
hydraulic ram is within the capacity of the
SRP12 pump. For the pilot to operate efficiently,
the cubic capacity of the boat's ram must be less
than 250cc (15 in 3 ). With hydraulic systems the
ram size is related to the steering load.
• If the volume of the ram cylinder is not known
then an approximate calculation can be made for
a balanced cylinder (these have the rod emerg-
ing from both ends of the cylinder - unbalanced
rams have the rod emerging from one end only
- Fig 4.1).
Volume = 3.142 x S(R 2 - r 2 )
S = Stroke length
R = Cylinder bore radius
r = Push rod radius
If S, R and r are in inches, the volume will be in
cubic inches (in 3 ). If they are in centimetres, then
the volume will be in cubic centimetres (cc).
An ideal location for the pump is in a
gas/inflammable vapour free area, where it will
not be immersed in water.
The pump accepts hoses with 1 ⁄ in NPT fittings.
4
NPT to BSP adaptors are supplied with European
versions to convert BSP hoses to NPT type if nec-
essary (Fig 4.2).
• Try to keep hydraulic fluid loss during connec-
tion to the pump as low as possible - this will
help to reduce the time and effort required later
to bleed the system of trapped air.
• Absolute cleanliness is essential - even the
smallest particle of dirt could clog the check
valves in the pump.
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Balanced
Unbalanced
Fig 4.1 - Hydraulic ram types
NPT System
BSP System
Fig 4.2 - SRP12 pump hose connections
Components supplied -
M5 x 25mm st stl hex set screw x 4
M5 st stl plain washer x 8
M5 st stl full nut x 4
in(NPT) - in BSP adaptor x 3
1 1
/ / (European version only)
4 4
Fig 4.3 - Hydraulic pump & mounting dimensions
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