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ULTRAFLEX
Installation and Maintenance Manual
1 PRODUCT DESCRIPTION
1.1 Hydraulic steering system operation
All ULTRAFLEX hydraulic steering systems are designed in conformity with
pump
UNI-EN-ISO 10592 and A.B.Y.C. P21 regulations.
engine
All ULTRAFLEX 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 mate-
rials and working processes which offer long life and safety under the
most extreme conditions.
cylinder
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
hydraulic hose
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. ULTRAFLEX produces different pump models, which have different capacity (cm
of oil moved
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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
[1,7cu.in.] and the cylinder has a volume of 120 cm
[7,3cu.in.], the
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3
formula looks like this: 120/28=4,2. Accordingly, the steering wheel will turn 4,2 times 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).
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HYDRAULIC CYLINDER FOR OUTBOARD ENGINE
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