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MECHANICAL STEERING SYSTEMS 6
MECHANICAL STEERING SYSTEMS
SUGGESTIONS
AND
WARNINGS
WHEN
SELECTING A
MECHANICAL
STEERING
SYSTEM
ADVANTAGES OF
A PLANETARY
GEAR DESIGN
Selection of the appropriate mechanical steering system is an important factor for the
safety and functionality of your boat.
The combination of engine power, hull type and boat speed influence the correct
selection of the steering system.
The load on the steering system increases with the boat speed and engine power; the
torque generated by the propeller rotation in high power outboard applications can
make it hard to steer.
Big boats with displacement hulls and inboard or non power assisted stern drive
engines, can generate high rudder loads: in these cases a mechanical steering system
will be inadequate and we suggest the use of an Ultraflex hydraulic steering system.
We always recommend consulting qualified personnel when selecting, installing and
maintaining a steering system for your boat.
EFFICIENCY
COMPARISON
TESTS
Test configuration:
3 bends at 90°; 1000N
load
NOTE: indicated
figures have been
obtained after 500
cycles of running
from samples bought
from after-market
sources
Ultraflex mechanical steering helms T71 FC, T73 NRFC as well as dual cable versions
and tilt wheel versions use a Planetary Gear Design. A Planetary Gear Design has
three satellite gears that rotate on their axis and at the same time rotate around
the central helm axis. This allows for equal distribution of engine torque over
three points of the central gear, dividing and balancing the system loads. The
benefits of this special design are increased system longevity, increased efficiency
and less engine feedback compared to single pinion gear helms.
2
1
3
Ef
ficiency
Tension
T71 FC Planetary gear design steering with M66 (Ultraflex)
Compression
Average
T85 Direct transmission steering with M66 (Ultraflex)
Direct transmission steering of well known competitor brand (T)
Direct transmission steering of well known competitor brand (M) 7
MECHANICAL STEERING SYSTEMS
USE AND
MAINTENANCE
The steering cable must be installed avoiding excessive and/or tight bends. This will
provide the driver with easy handling at all speeds, helping to reduce system
inefficiency, and excess play in the system.
Marine corrosion may cause the materials to deteriorate affecting maneuvering
efficiency and in the worst case, system failure. By following the engine manufacturer
specifications, the steering cable end fittings and the engine cable support must be
cleaned and greased periodically; these simple operations minimize wear and
corrosion in the system.
The steering cable must be regularly inspected. If steering becomes hard,
inconsistent, cuts on the conduit surface are noticed, or any other component found
damaged, the cable must be replaced immediately.
When storing your boat for an extended period of time we recommend removing the
steering cable end fitting from its engine side support and cleaning it adequately.
THE
IMPORTANCE
OF A NON-
REVERSIBLE
STEERING
SYSTEM
FOR
INCREASED
SAFETY
The steering system of a boat is the mechanism that determines the boat direction
when the steering wheel is turned.
If, for any circumstance, the driver does not hold the steering wheel, a dangerous
situation may occur caused by a sudden change of direction of the boat due to
external forces (waves, currents, etc.) or internal forces such as rudder torque
originated by the way of rotation of the propeller.
Engine torque usually generates a load on the steering system that must be
continually compensated for by the driver even when the boat is going straight. The
additional effort by the driver to maintain a true course can often cause fatigue.
With Ultraflex Non-Reversible steering helms T73NRFC, T74NRFC, T83NRFC,
T84NRFC the loads applied to the steering system are no longer a problem.
A special patented device allows the helm shaft to lock until turned by the driver,
maintaining the boat direction and neutralizing the feedback loads on the steering
cable.
This mechanism is engaged when the driver is not turning the wheel and is
automatically disengaged as soon as the driver applies pressure on the wheel to
change direction of the boat.
The Ultraflex Non-Reversible mechanism makes driving a boat safer and easier. 8
MECHANICAL STEERING SYSTEMS
SELECTION
OF
STEERING
SYSTEM
AND CABLE
LENGTH
MEASUREMENT
HOW TO
MEASURE
FOR NEW
STEERING
CABLE
INSTALLATION
TRANSOM SUPPORT OR SPLASHWELL MOUNTING - Fig. 2-3
Example:
A (2.5) + B (10.5) + C (3) = 16
16 - 8 (two 90° bends) = 154
Round up to 16
TILT TUBE MOUNTING - Fig. 1
Example:
A (2.5) + B (10.5) + C (3) = 16
16 - 8 (two 90° bends) = 154
154 + 12 (tilt tube) = 164
Round up to 17
Add the lengths of A + B + C together
and subtract 4 (10 cm) for each 90°
bend.
Add 12 (30,5 cm) for the engine tilt
tube.
To order in foot length, round up to
the nearest whole foot.
Fig. 1
Fig. 2
Fig. 3
APPLICATION
BOAT LENGTH
STEERING
SYSTEM
Twin cable systems
are recommended
for boats that
exceed 50 mph.
Always follow
engine
manufacturers
instructions.
OUTBOARD
up to 35 (10.5m)
T71FC - T81FC - T73NRFC
- T83NRFC - T86 - T88NR
T96 - T98NR
twin cable rotary
steering systems
INBOARD
NOTE: sterndrive engines not equipped with power steering can create very high steering loads. Our
hydraulic steering systems are recommended for these type of boats. For any further information
please contact our Technical Service Department.
T71FC - T81FC - T73NRFC
- T83NRFC - T86 - T88NR
T96 - T98NR
twin cable rotary
steering systems
STERNDRIVE
POWER ASSISTED Speed, hull, horsepower, engine type,
displacement and size are major factors in
boat performance and handling cha-
racteristics. The above selection guide
should be used as a general reference only. One of the major factors in selecting a
steering system is proper cable length.
Due to specific routing in each boat, these
approximate lengths will vary. Final selection
should be made with the assistance of a
qualified technician. Ultraflex mechanical steering systems
should not be used on boats equipped with
engines that exceed the maximum
horsepower rating of the boat.
up to 30 (9m)
T71FC - T81FC
T73NRFC- T83NRFC -
T86 - T88NR T96 -
T98NR
twin cable rotary
steering systems
HOW TO
MEASURE
FOR
REPLACEMENT
STEERING
CABLES
ORDER LENGTH: D dimension + 22and round up to the next whole foot
Example: D= 120 + 22 = 142 (118). Round up to 12 ft
D = Conduit length 9
MECHANICAL STEERING SYSTEMS
STEERING HELM
ULTRAFLEX
REPLACEMENT CABLE
ADAPTOR
REQUIRED
Ultraflex P15 - P22
M55
Ultraflex T71FC -
T72FC - T73NR FC -
T74NRFC - T81FC -
T82FC - T83NR FC -
T84NR FC
Teleflex
®
Safe -
TQC
®
/NFB
®
-
Morse
®
D290
Ultraflex year 2001
and prior:
T71 - T72 - T73NR
T74NR - T81 - T82
T83NR - T84NR
M66
none
K66 - 38432Q
Ultraflex year 2001
and prior:
T71 - T72 - T73NR
T74NR - T81 - T82
T83NR - T84NR
Ultraflex T71FC -
T72FC - T73NR FC -
T74NR FC - T81FC -
T82FC - T83NR FC -
T84NR FC
Morse
®
D290
Teleflex
®
Safe - T
®
-
Big-T
®
M47 - DISCONTINUED
USE M66 + K66
none
K46-35679L
none
REPLACEMENT
STEERING
CABLES
Teleflex
®
ATB RACK -
SSC122
none
M55 AD
M86
NOTE: Will not work with dual cable helms
Ultraflex G86 - G88NR
G96 - G98NR
Morse
®
Command 200
Teleflex
®
THE RACK
SSC-124
none
M68 + M67D
Dual station steering
systems:
Ultraflex T71FC
none
Part numbers for ordering:
M55 XLL
LL = Length of cable
M66 XLL
LL = Length of cable
M47 XLL
LL = Length of cable
M86 XLL
LL = Length of cable
M68 XLL
LL = Length of cable
M67D XLL LL = Length of cable 10
P
ACKAGED STEERING SYSTEMS
ULTRAFLEX STEERING SYSTEM
PACKAGED IN A BOX
A convenient kit form, especially suitable as
replacement steering, that includes helm,
bezel and cable.
The cable is available in 1-ft increments from 8
to 20 feet (specify cable length when ordering)
The wheel is not included
ROTECH
TM
ROTARY STEERING SYSTEM
ROTECH - I XLL - LL= Length
T 71FC
- helm
X 34
- 90° bezel
M 66
- steering cable
ROTECH - II XLL - LL= Length
T72FC
- helm-dual
X 34
- 90° bezel
M 66
- 2 steering cables
ACCURA
TM
ROTARY STEERING SYSTEM
ACCURA - I XLL - LL= Length
T73NR FC
- helm
X34
- 90° bezel
M66
- steering cable
ACCURA - II XLL - LL= Length
T74NR FC
- helm - dual
X34
- 90° bezel
M66
- steering cable
RACKTECH
TM
RACK AND PINION S. SYSTEM
RACKTECH XLL - LL= Length
M86
- preassembled helm with
steering cable
G86
- shaft assembly
X 34
- 90° bezel
ACCUTECH
TM
RACK AND PINION S. SYSTEM
ACCUTECH XLL - LL= Length
M86
- preassembled helm with
steering cable
G88NR
®
- non-reversible shaft
assembly
X34
- 90° bezel
PACKAGED STEERING
SYSTEMS 11
MECHANICAL STEERING SYSTEMS
T71FC AND T72FC ROTARY
STEERING SYSTEMS
A COMPLETE STEERING SYSTEM
CONSISTS OF: Steering helm:
T71FC - 38867 H - single cable steering helm
T72FC - 38868 K - dual cable steering helm Black mounting bezel:
X34 - 36654 B - 90° mounting
X35 - 36655 C - 20° mounting Steering cable: M66 (Note: two M