HYDRAULIC CYLINDER FOR SIDE MOUNT APPLICATIONS
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page 7
of 23
Installation and Maintenance Manual
The UC 68-OBS, UC 132-OBS and UC 133-IOB side mount cylinders must not be installed on race boats.
Dual engine applications require two steering cylinders and tie bar, when the combined engine horsepower
exceeds 450hp, and/or when the boat speed exceeds 55 m.p.h.
All
ULTRAFLEX
steering systems must not be installed on boats equipped with engines whose maximum
horsepower is higher than the horsepower rating approved by boat manufacturer.
1.2 Warnings for the product correct use
Before beginning the installation, check the mounting compatibility of the UC 68-OBS, UC 132-OBS and UC
133-IOB cylinders to the engine by consulting the attached document "Application Guide" contained in the
packaging.
WARNING
WARNING
WARNING
WARNING
DANGER
1 PRODUCT DESCRIPTION
1.1 Hydraulic steering system operation
l
engine
l
h y d r a u l i c
hose
l
cylinder
l
pump
All
UFLEX
hydraulic steering systems are designed in conformity with UNI-EN-ISO 10592 and A.B.Y.C. P21
regulations. All
UFLEX
steering systems can operate at temperatures between -18°C (0°F) and +77°C (+170°F).
All the components are made for the marine environment, using materials and working processes which
offer long life and safety under the most extreme conditions. A hydraulic steering system consists of a
steering pump, a cylinder tied to the rudder or to the outboard or
sterndrive engine and the connecting hoses (see picture). Under
normal operating conditions, a turn of the steering wheel will pump
the oil, which flows in through the hoses to the cylinder, according
to the turn direction. With the consequent cylinder movement the
oil will flow to the pump through the hoses and at the same time
moves the engine or the helm which are connected to the cylinder.
The pumps are equipped with a valve, which prevents outgoing
fluid from returning along the same hose. It also allows the operation
of the steering systems with two or more steering stations. The
cylinders are double acting and may be balanced or unbalanced.
In the unbalanced cylinders the two chambers have different
volumes and so they need a different number of turns of the steering
wheel and a different rotation effort. The balanced cylinders have
same number of steering wheel turns in order to move the helm from the center to the end stroke in the two
opposite directions. A well balanced steering system needs a correct choice of the pump for the cylinder.
UFLEX
produces different pump models, which have different capacity (cm
3
of oil moved each steering wheel
turn) and for each type of installation. While choosing the pump it is important to consider the cylinder
volume. The number of starboard and port turns is determined by the ratio between the cylinder volume
and the pump capacity.
Example
: if the pump has a capacity of 28 cm
3
[1,7cu.in.] and the cylinder has a volume of 132cm
3
[7,3cu.in.], the
formula looks like this: 132/28=4,7. Accordingly, the steering wheel will turn 4 times and an half before the
cylinder will completely turn from one side to the other. In case of installations with double cylinders
connected in parallel the cylinder volume must be added. Applications with less than 4 turns are not
recommended, as they need a higher effort, also applications with more than 8 turns are also not
recommended, as the response of the boat to steer is slowly. The maximum operating pressure is 7,0MPa
(70 bar) (1000 PSI).
Do not modify the steering cylinder in any way to fit it to your engine application, otherwise the cylinder will
no longer operate in safety and it will endanger the boat and the occupants.
