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Steering Overview

3
®
STEERING - Overview
Mechanical cable steering is durable and reliable
and comes in two main forms, each of which has
advantages in specific applications.
They are:
• Rotary (cable wraps around a gear).
• Rack & Pinion (cable attached to rack gear
moved by a pinion).
All mechanical steering systems except Big-T are
for single station use only. Hydraulic steering is the
perferred system for dual station boats.
ROTARY STEERING (2 TYPES):
Various Rotary helms are available, each resulting
in a different number of lock-to-lock steering wheel
turns. All SeaStar Solutions helms feature a unique
mounting plate that allows installation at several
angles to accommodate the many space constraints
which occur behind all dashboards. Most versions
are available with No FeedBack (NFB) technology.
NFB is recommended for all outboards and stern
drives without power-assisted steering. HPS and
Safe-T QC are offered for most boats with power-
assisted steering. Big-T is a good choice for small
inboards, especially those with twin stations.
There are two main rotary helm designs:
Reduction Gear Type: (one or more gears mesh
externally with the drum to move the helical core of the
steering cable). This is the best rotary design in terms
of strength and efficiency as there are usually only
two gears. The one drawback is that the helm shaft
must be placed outside the cable drum, resulting
in a fairly large round helm behind the dash. These
helms often cannot be used in small dashboards.
The original, time-proven SeaStar Solutions helms
such as Big-T® and Safe-T® were designed with
reduction gears, resulting in simple, efficient
gearboxes. With smaller, more crowded dashboards
came the need for a more compact helm, thus one
with planetary gears to save space.
Planetary Gear Type: (three or more gears mesh
internally with the cable drum to move the helical
core of the steering cable). This is an alternative
rotary design whose purpose is to take up the least
possible space behind the dash, useful in boats with
small dashboards and/or instruments clustered right
around the wheel.
RACK AND PINION (1 TYPE):
There is only one kind of Rack and Pinion. A pinion
gear hobbed directly into the helm shaft engages
a rack gear in a tubular housing. Rack and pinion
steering is the most efficient mechanical approach to
moving the cable. The drawback is that it requires
a long tubular rack housing and cannot fit behind
many dashboards. SeaStar Solutions rack mounting
allows installation of the rack tube at several different
angles, but because it is very long, there is not as
much mounting flexibility as with rotary helms. The
Rack (without the NFB feature) is offered for most
boats with power-assisted steering.
DUAL (TWIN) CABLE SYSTEMS:
All mechanical steering systems rely on a push-
pull cable to do the work of moving the engine or
rudder. The efficiency of the system depends on the
efficiency of the cable. By virtue of their design, all
cables have some backlash or lost motion. While this
is acceptable for most boats, some high performance
boat/engine combinations develop instability at high
speed. Instability becomes more prevalent in boats
faster than 50 MPH. Dual cable (or SeaStar PRO)
steering is recommended by SeaStar Solutions and
engine makers for these boats. Dual cable steering
allows adjustment at the engine of one steering cable
versus the other to remove most of the backlash (free
play) inherent in even the best mechanical systems.
This reduction of backlash helps minimize engine
flutter and the resulting handling instability.
Mechanical and Hydraulic Steering Overview
Generally, it is a good practice to replace a steering
system with one of the same type: rotary with rotary
(i.e. Safe-T
®
), rack with rack (i.e. The Rack™), hydraulic
with hydraulic (i.e. SeaStar®), etc. Use a steering
system with the same number of steering wheel turns
lock-to-lock as the original system.
This insures the boat continues to perform in
maneuvers as designed and makes installation of the
replacement system as simple as possible.
Changing the type of steering on a boat requires
some careful consideration. Your steering system was
selected by the boat builder based on the following
criteria:
• Fit: steering components accommodate dash
design and splashwell dimensions.
Performance: meets manufacturer’s performance
specifications.
Value: quality products supplied by a reliable,
experienced company that stands behind them.
Any change from the original steering system
may affect the handling and feel of the boat. In
addition, installation may be further complicated
by modifications needed to accommodate
components for which the boat was not originally
designed.
About Our Mechanical Steering Designs