The advantage of 4.2 turns lock-to-lock over the 3.0 turns is that you will exert less effort when steering, although the turning response time will be slower. This helm offers more fine tuning and control when steering.
This SeaStar Solutions 4.2 Rotary NFB Steering kit offers the advantage of 4.2 turns lock-to-lock plus Teleflex's patented No FeedBack Steering Control for about the cost of an old-fashioned steering replacement.
While single cable steering kits are suitable for well-behaved, single station, non-power-assisted outboard and sterndrive engines up to V-6, this rugged dual cable system is made for any of the preceding installations that exhibit engine flutter or steering instability.
All mechanical steering systems rely on a push-pull cable to do the work of moving the drive unit. The steering efficiency (percentage of your steering effort that actually gets transferred to the drive housing) depends to a large extent on the backlash inherent in the cable.
By virtue of their design, all cables (even the best) have some degree of backlash or lost motion. Lost motion is the difference between the amount of movement at the input end of the steering cable compared to the movement at the output end. This motion is lost in "take-up" between the inner core of the cable and the cable's outer conduit. Backlash is experienced by the operator as free play (slop) in the steering wheel.
While some degree of backlash is acceptable on most boats, certain high performance boat/engine combinations exhibit engine flutter and steering instability when there is a high degree of backlash. The instability becomes magnified at higher speeds - especially above 50 mph.
Dual cable mechanical steering systems are recommended by SeaStar Solutions as well as engine manufacturers for these boats.
With dual cable steering systems, one cable can be adjusted at the engine to counteract the backlash in the other cable, and vice versa. This negates most of the backlash effect — reducing engine flutter and the resulting handling instability.
• Patented No FeedBack™ steering mechanism
• Comfortable 4.2 turns lock-to-lock provides precise steering
• Twin cable system available for maximum control
• Standard 3/4" tapered shaft
• Stainless steel cable output ends resist corrosion
• Fast, easy installation using Quick connect (QC) steering cable(s)
• Meets ABYC standards and NMMA certification requirements
• Note: tilt helm available - single cable helm TFX #SH91526P and dual cable helm TFX #SH91527P
Kits include: QC Cable (SSC62xx) (2 cables for dual systems), helm (SH4910P single, SH4920P dual), 90° bezel (SB27150P), and hardware.
* What is NFB?
NFB stands for No FeedBack, and is an exclusive feature built into SeaStar Solutions helms to fight propeller torque feedback.
In standard mechanical steering systems, the turning of the propeller creates a torque force which can be felt in the steering wheel as a tendancy for the boat to constantly want to turn in one direction. To keep the boat going straight, this veering must be constantly "fought" by the person steering the boat.
A corollary effect is that the boat can be turned in one direction with just one finger, but requires two hands to turn in the other direction. This is especially apparent with larger engines (over 40 - 50 horsepower), as well as at higher speeds.
For about a hundred bucks more than a standard helm mechanism, SeaStar Solutions NFB helms incorporate an internal clutch mechanism that significantly decreases the tiresome effect of prop torque — without having to spend an extra thousand dollars for an hydraulic system to completely eliminate it.
Whereas, when you take your hands off the wheel with a standard mechanical steering system the boat will quickly start to turn of its own accord, with an NFB system that turning tendency will be much slower to start and can be controlled with less effort.
A hydraulic system, on the other hand, will completely eliminate propeller torque feedback, so you can take your hands off the wheel, and the boat will continue to track straight (all other things being equal). Hydraulic steering is a real advantage with larger engines, and is highly recommended for those applications.
In case you were wondering, boats with inboard engines do not experience prop torque since you steer them with a rudder, not by having to turn the entire drive unit and propeller - as with an outboard or I/O.
NFB steering helms should never be used with autopilots or power assisted steering systems.