Specifications

192
Engine & Steering Controls
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Manual Steering Systems
Fluid is added to the System at the Reservoir.
For the 2-Line compact Helm, the 60, the
Reservoir is part of the Helm Unit. For other
pressurized systems, the Reservoir is a sepa-
rate component which may be located any-
where in the system to conveniently monitor
fluid level and system pressure.
The Relief Valve provides overpressure pro-
tection for both the mechanical steering link-
ages and the hydraulic lines and fittings. Re-
lief pressure is factory set at either 500 psi or
950 psi. The new compact 60 Series Helm
Unit used in the 2-Line compact systems has
an internal relief valve. For pressurized com-
pact systems, the relief valve is attached un-
derneath the Reservoir in a single component
called the Reservalve.
The Cylinders are double acting and may be
balanced or unbalanced - the rod end extends
through only one end of the Cylinder. Incom-
ing fluid from the Helm Unit pushes a piston
which is pinned to the external rod. As the
piston is moved the rod is either extended or
retracted.
Under normal operating conditions, a clock-
wise turn of the steering wheel will send
fluid from the Helm Unit into a starboard
hydraulic line. This fluid will be pumped
into the Cylinder and either extend or re-
tract the cylinder rod. Outgoing fluid from
the other end of the Cylinder is returned to
the Helm Unit via the port side line. A
smaller, central line, evident on all pressur-
ized systems links the remote Reservoir
with the helm.
There are four basic parts to any Hynautic
Manual steering system. These are the Helm
Unit, the Reservoir, the Relief Valve and
the Cylinder. Each may be a separate com-
ponent or, as in the case of the new 2-Line
Compact System, the Reservoir and relief
Valve are located within the Helm Unit.
The components are connected by copper
tubing or synthetic tubing or hose.
The patented Helm Unit consists of a hy-
draulic pump section and a valve section.
The pump section contains one or two bidi-
rectional piston pumps which are activated
when the ship's wheel is rotated. Hydraulic
fluid is efficiently pumped from this sec-
tion through valves into the lines. The valve
assembly located at the back end of the
Helm Unit prevents outgoing fluid from
returning, eliminates pump cavitation, iso-
lates non-operating steering stations, locks
the rudder and eliminates rudder "kick-
back" to the Helm wheel.
System Number
Application
Prefix
No.
Cylinders
System Numbering Code
There are many variables which are
taken into consideration when order-
ing a compact steering system. The
following numbering code illustrates
how compact system numbers are
derived:
OB 260-11
No. Steering
Stations
How The Systems Work
HYNAUTIC MANUAL
STEERING SYSTEMS
ARE UNIQUE. The
design of the patented helm
pump features both a pump
section which increases
volumetric and mechani-
cal efficiency, and a valve
section which incorporates
all the lockout capabilities.
Most Hynautic Systems
are pressurized which pre-
vents air from entering the
system, helps to monitor
system status and assists
in purging.
All components are made
exclusively for the marine
environment, using mate-
rials and workmanship
which offer longevity and
safety for the most extreme
conditions.