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Smooth Moves

Dec 8, 2017 Boat Maintenance ,Technology

Mechanical cable steering is used on the vast majority of outboard-powered trailer boats, and one of the most common problems greeting owners bringing vessels from winter hibernation, says Gary Appleby, product manager at BLA New Zealand, is a semi-seized helm

“Unfortunately, the instinctive reaction is wrestling the helm back and forth in a bid to ease the action, but that often damages the helm unit behind the dash. That mistake is not only inconvenient at the start of the season, it potentially leads to a costly repair bill. Don’t do it.”

BLA is the local agent for SeaStar outboard steering and engine control systems, and Appleby says identifying the cause of a sticky helm – and fixing it – is usually an easy DIY job.

“In most cases the problem can be traced to the cable being seized in the tilt tube, a component on the engine through which the steering cable runs.

“Although the steering cable output is stainless steel, the engine’s tilt tube is usually steel. This area’s exposed to plenty of sea water and can be subject to a lot of salt build-up and, if left unattended, it may rust. If you haven’t prepared the mechanism for the winter lay-up by dismantling it and greasing it, chances are it will seize up after a few months of disuse.”

Assuming you haven’t done the prep work, it’s a relatively simple task to dismantle the linkage, though if the cable is badly seized in the tilt tube it may not be able to be removed without destroying it. Once it is removed, clean the inside of the tilt tube (scrubbing with a brass wire brush works well) as well as the stainless cable end, apply some marine grease and reassemble.

While a corroded tilt-tube/cable interface is a common cause of a sticky helm, there are others and the best way to identify the source of friction is by a process of elimination.

“Other common problems,” says Grant Matthew, product manager at Lusty & Blundell, “are poorly-routed, corroded or worn cables. Consider that conventional steering cables are designed for a maximum radius-bend of around 150mm.” Lusty & Blundell distributes Ultraflex steering and control cable systems.

“Forcing a cable around tighter corners inevitably results in binding between the inner core and outer lining. More friction means harder steering. Often a poorly-installed cable will develop a kink which adds to binding.”

Poorly-installed cables wear prematurely and will need to be replaced. Cables should be routed with as few bends as possible to eliminate backlash and steering inefficiency.

While the inner core of a steering cable is protected from seawater ingress by seals (one at the end of the tilt tube and another at the end of the cable itself), the seals do wear and might even sustain damage. Once seawater’s entered the core, it’s difficult to prevent salt build-up and corrosion.

Be aware that a reluctant helm might have nothing to do with the steering cable – sticky engine pivots points (pintles) which haven’t been greased regularly are another possible cause. To identify the source of the problem, says Appleby, “disconnect the steering cable from the tilt tube and test the helm. If it moves freely the problem’s likely to be the tilt-tube or engine-related. If it still feels sticky, chances are the cable is worn, damaged or corroded and will need to be replaced.”

Wouldn’t removing the steering cable and giving it a good clean and lubrication fix a corrosion/salt build-up issue?

Appleby says this is a myth: “We’re all familiar with stories of boat owners hanging a cable from a high ceiling and fashioning a funnel at the top to force diesel and oil down in a bid to clean and lubricate the cable.

“The truth is, steering cables are pre-lubricated at the factory and the lubricant’s designed to last the duration of the cable’s life. A DIY diesel clean and oiling might work for a few months, but the reality is the cable’s days are numbered. A replacement is a far more prudent, and probably an easier process.”

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Two kinds of helm units (located behind the wheel/dash) dominate the trailer boat market: the rotary and rack & pinion models. Rotary models are cheaper and require much less space under the dash, and are therefore more popular.
Neither give much trouble (if you don’t force them!), but if you do need to replace the entire steering system, it’s worth considering installing a non-feedback helm (if you don’t already have one).

Non-feedback helms force the engine to maintain its orientation if you let go of the wheel, a significant safety feature when the boat has an inexperienced skipper  and especially if it’s powered by a high-torque outboard.

Boats without non-feedback helms respond to high-torque outboards in a very predictable way: you have to fight against them hiving off to the right or left (depending on the direction of prop rotation). The cost of a non-feedback steering system is about 40 percent more than a conventional cable steering system, says Appleby.

Note that helm units are equipped with various reduction ratios. These determine how many turns are required (hard-over to hard-over). Perhaps more importantly, they also determine the ‘ease’ of the helm’s action. A unit that requires three turns (full port to full starboard) will be harder to turn than a slower helm that requires four or five turns. Ask the retailer for advice.

Note also that size of the wheel relates directly to effort. Small ‘racing’ wheels might look cool but basic physics tells you they’ll feel a lot heavier and be more difficult to turn, especially on larger outboards.

Sticky cables aren’t unique to steering systems – throttles and gear shift cables suffer from identical problems of poor routing, wear, corrosion and damage.

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If the action is stiff, says Appleby, check the adjustment at the control end and the engine end.

“The alignment must be perfect so that there’s no load or tension on the mechanism when the engine’s in neutral and idling. Check the cable for kinks. A common fault is caused by a poor installation, where the outboard repeatedly creates a kink in the cable as it’s titled up.”

Another common problem results from an over-zealous cable installer – one who runs the control cable neatly around the vessel, keeping it place with nylon ties. If these ties are too tight, says Appleby, they can inhibit the movement of the cable, leading to binding. The cable must be able to flex.

As with steering cables, control cables are pre-lubricated and don’t require any post-installation lubrication. What does need regular lubrication is the ball joint or clevis connection between the cable end and the engine actuator.

If your control cable has reached the end of its life it’s worth considering switching to a low-friction model such as Seastar’s Extreme cable. Where standard control cables have a solid stainless steel (1.9mm) inner core, the low-friction models have a multi-strand core.

“They’re a lot more flexible,” says Appleby, “and as they accommodate tighter bends it’s a lot easier to route around a boat.” The low-friction cables, he adds, are also more precise and provide more accurate shifting. They are about 40 percent more expensive than standard cables.

The bottom line? Regular maintenance, and especially pre-winter preventative maintenance, will prolong the life of your steering and shift/throttle cables. Even so, they have a finite life and installing a new set offers a great opportunity to upgrade to newer, easier technology.

 

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