Ultraflex Group

Selection of steering system

Selection of steering system Outboard steering systems HYDRAULIC STEERING SYSTEMS

Selection of steering system

All the components of Ultraflex hydraulic steering systems are made specifically for the marine environment, using materials and working process which offer long life and safety for the most extreme conditions.

 

HOW THE SYSTEM WORKS

A manual hydraulic steering system consists of a helm, which pumps hydraulic fluid through two hoses to a hydraulic cylinder which is mounted to an engine or rudder.
While steering, hydraulic oil is pushed through hoses into two chambers within the hydraulic cylinder. Depending upon which direction you steer, one of the two chambers is filled or relieved of oil, thereby changing the course of the boat.
While not actively steering, the torque (hydraulic pressure in the hoses) is held by a one way valve in the helm, which eliminates the transmission of the torque "feedback" to the steering wheel.
The number of turns from full lock-to-lock has a relationship to ease of steering. Generally speaking, the more number of turns lock-to-lock the easier the boat will be to steer and vice versa.
Because of the variety of applications and handling characteristics of boats, the number of turns lock to lock is often a matter of personal preference. As a general rule, the first priority should be ease of steering, then number of turns lock to lock. However, it is not recommended to have fewer than 4 turns lock to lock on high performance boats.
To calculate number of turns lock to lock simply divide the cubic inch displacement of the cylinder by the cubic inch displacement of the helm.

 

Other factors that can significantly affect the amount of effort to steer the system can be:
• Fittings introduced between the helm and cylinder that restrict fluid efficiency
• Oil viscosity
• Type of hose and inside hose diameter.
• Vessel speed
• Trim angle
• Rudder dimension, or engine power
• Propeller selection
• Hull type (displacement, planing, etc.)
• Sea conditions

 

SUGGESTION AND WARNINGS WHEN SELECTING A HYDRAULIC OUTBOARD STEERING SYSTEM

OUTBOARD CYLINDERS Maximum power rating applicable

Cylinder

model

 

Single engine

single cylinder

 

Double engine single cylinder

Double engine double cylinder

 

NON counter

rotating propellers

 

 

Counter

rotating propellers

 

 

NON counter

rotating propellers

 

 

Counter

rotating propellers

 

Max hp power Max hp power Max hp power Max hp power Max hp power
UC81-OBF 115 not applicable not applicable not applicable not applicable
UC94-OBF 150 not applicable not applicable not applicable not applicable
UC68-OBS 150 not applicable not applicable not applicable not applicable
UC128-OBF 300 300 500 500 600
UC128-SVS 350 350 600 600 700
UC132-OBS 300 300 450 500 600

 

WARNING: These recommendations should be used as a general reference only. Final selection should be made with the assistance of a qualified installation technician. For any further information please contact our Technical Service.

 

STEERING WHEEL TURNS single cylinder
 

UP18

18cc

UP20

20cc

UP25

25cc

UP28

28cc

UP33

33cc

UP39

39cc

UP45

45cc

UP25-SVS

25cc

UP33-SVS

33cc

UP39-SVS

39cc

UC81-OBF 4,5 - - - - - - - - -
UC94-OBF - 4,7 - - - - - - - -
UC128-OBF - - 4,8 4,3 3,6 3,1 - - - -
UC128-SVS - - - - - - - 4,8 3,6 3,1
UC68-OBS - 3,4/5,0 - - - - - - - -
UC132-OBS - - 5,3/6,5 4,7/5,8 4,0/4,9 3,4/4,2 2,9/3,6 - - -
UC133-IOB - - 5,6 4,7 4,0 3,4 2,9 - - -

 

STEERING WHEEL TURNS dual cylinder
 

UP28

28cc

UP33

33cc

UP39

39cc

UP45

45cc

UP33-SVS

33cc

UP39-SVS

39cc

UC128-OBF - 7,3 6,2 5,3 - -
UC128-SVS - - - - 7,3 6,2
UC132-OBS - 8,0/9,8 6,8/8,4 5,8/7,2 - -
UC133-IOB - 8,0 6,8 5,8 - -