Technical Reference Manual
All Teleflex Marine steering systems exceed A.B.Y.C. safety standards as well as ISO/ I.M.C.I./N.M.M.A. certification requirements,
and feature corrosion-resistant materials.
Because steering forces vary considerably
in the variety of boat and motor
combinations available, selection of the
most appropriate system is critical.
Teleflex will provide assistance in this when
requested. When making a steering system
selection, the following critical areas must
The combination of boat speed and engine
horse pow er exert varying loads on steering
systems. Engine horse power must not
exceed maximum horsepower rating of
Some high performance boats/engine
combinations develop instability at high
speed. Instability becomes more prevalent in boats faster than 50 MPH. Dual-cable mechanical steering or SEASTAR PRO®
systems are recommended by Teleflex and
engine makers for these boats.
Corrosion and build up of dirt or salt
deposits at the point of the cable
connection to the engine will lead to stiff
operation and possibly complete seizure.
It is necessary to periodically remove cable
from the engine, clean both cable output
end and tilt tube thoroughly, lubricate
with water proof grease, and reassemble
correctly. Together with regular cleaning
and lubrication, Teleflex Cable Gard
helps prolong cable life by keeping
lubrication in and dirt out. We recommend
it for all engines with tilt tubes.
The routing of a steering system should
be chosen to minimize bends and kinks.
Obstructions, sharp edges, and/or chaffing
must be completely avoided.
All boats should be water tested to ensure
safe, dependable operation. The trim tab
setting and engine tilt position are critical
for safe steering of outboard motors. The
engine makers manual gives instructions
for the correct settings. These must be
followed and all boats should be water
tested to confirm these settings for safe
and dependable steering.
Correct adjustment of the trim tab on the motor
and engine tilt is essential. Follow motor
The mounting position of the outboard can affect
steering loads and boat handling. Follow motor
When Replacing Steering, Try to Retain the Type Originally Installed on the Boat:
Generally, it is a good practice to replace
a steering system with one of the same
type: rotary with rotary (i.e. SAFE-T
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
This insures the boat continues to perform in
maneuvers as designed and makes installation
of the replacement system as simple as
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
- Value: quality products supplied by a
reliable, experienced company that stands
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.
Steering Technology Has Improved!
With systems such as Teleflex mechanical
No-FeedBack (NFB Steering (HPS® and SeaStar Pro®,
marine steering technology has advanced significantly
compared to the available options of just a few years ago.
Upgrading the system to NFB or SeaStar
is recommended for all non-power-assisted
outboards. SeaStar Pro is recommended for
all high speed single outboards (55-75 MPH).
Upgrading to HPS or SeaStar is recommended
for small boats with power-assisted steering.
The same general rule applies: replace rotary
with rotary, rack with rack, hydraulic with
For that reason, Teleflex offers many different
NFB and SeaStar systems: there is one to
match the type and number of turns for nearly
every marine steering system ever made
(except rope and pulley, of course).
What if The Driver Wants Easier (or More Responsive) Steering?
A driver may want faster response or lower
steering effort. NFB, SeaStar and HPS offer
upgrade paths to either increase steering
response or reduce steering effort.
When changing steering, water test the boat
after installation to ensure safe, dependable
operation. Using caution, the driver should
gradually become familiar with the new steering
system as some handling characteristics of the
boat may change.
Response vs. Effort
Steering wheel effort is directly proportional
to the number of wheel turns lock-to-lock.
The number of wheel turns lock-to-lock is
dependent on these factors:
- The gear ratio of the helm. Numerically
higher gear ratio = more wheel turns with
less effort. Lower gear ratio = less wheel
turns with higher effort.
- The displacement of the helm pump.
Higher helm displacement = less wheel
turns/faster response with more effort. Less
displacement = more wheel turns.
- The volume of the cylinder. More cylinder
volume = more wheel turns with less effort.
Less volume = less wheel turns with
Other factors that can influence steering effort are:
- Allowable movement of engine, rudder or
- Vessel speed.
- Type of engine (outboard, stern drive,
- Unusual propeller selections.
- Hull type (i.e., displacement, planing, etc.).
All boats should be water tested to ensure
safe, dependable operation!
|A Balancing Act:
|- More wheel turns lock-to-lock =
less steering effort, slower response
|- Less wheel turns lock-to-lock =
more steering effort, faster response
Why So Many Different Types of Steering
The great variety of boats dictate this: the
steering system which is right for a 14-foot
runabout with a 50 H.P. engine, would not be
right for a 25-foot offshore fishing boat equipped
with two 200 H.P. engines. Marine steering can
be divided into three major types:
- Mechanical (cable) steering
- Hydraulic steering
- Power-Assisted steering
Mechanical Steering Designs:
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 and Pinion (cable attached to rack gear moved by a pinion)
All mechanical steering systems except for Big-T are for single station use only.
Rotary Steering (2 types):
Various Rotary helms are available, each resulting
in a different number of lock-to-lock steering wheel
turns. All Teleflex 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 Teleflex helms such as
Big-T, Easy-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.
The drawbacks to the planetary gear
design are the many wear points and more
accumulated backlash (free play or "slop") from four
or more gears meshing versus two (typically) in a
reduction gear helm. Teleflex does not offer a planetary
gear helm for outboard engines larger than V-4.
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 major drawback is
that it requires a long tubular
rack housing and cannot fit
behind many dashboards. Teleflex
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
Dual (Twin) Cable Systems:
All mechanical steering systems rely on a pushpull
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 Teleflex 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.
Hydraulic Steering Designs:
A SeaStar hydraulic system is the most comfortable
and efficient approach to steering a boat. It is
durable and reliable, with a smooth, positive
response at the wheel. Several helm displacements
and cylinder options are available (except for
SeaStar PRO), allowing a choice in the number
of steering wheel turns to suit boat handling
characteristics and individual driving preferences.
All hydraulic systems exceed A.B.Y.C. safety
standards and ISO/I.M.C.I./N.M.M.A. certification
requirements and are constructed with high quality
corrosion-resistant materials. Hydraulic steering is
offered in two main forms:
Manual (helm pump moves cylinder directly).
These are available in two line systems (SeaStar)
and three-line systems (Hynautic). The advantage of
a three-line system is remote fill; the drawback is a
more complicated installation and maintenance. The
advantage of a SeaStar 2-line system is incredible
reliability and simplicity; the drawback is that you
have to be really careful not to spill when you add oil
because you fill at the helm.
Some high performance boats develop instability at
high speed, becoming more prevalent in boats faster
than 50 MPH. SeaStar PRO (or dual-cable mechanical
steering systems) are recommended by Teleflex and
engine makers for single-engine boats with these
handling characteristics. SeaStar PRO features special
helm valving to maintain equivalent line pressures,
which reduces the free-play (or deadband) at the
wheel, reducing steering instability at high speeds.
Power Assist (mechanical cable or hydraulic
helm moves servo, which directs pressurized
fluid from a pump to the steering cylinder).
Power assisted steering is the easiest to operate.
It is essential in many larger boats. The hydraulic
helm type is preferred as it offers unmatched
reliability, an easy autopilot interface and superior
manual back-up steering. SeaStar Power Steering
is a hydraulic helm type of system which is designed
for larger vessels.