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

OUTBOARD CYLINDERS

PACKAGED SYSTEMS