Boat Steering: Cable, Hydraulic and the Signs It's Wearing Out

Steering is the system boat owners think about least and depend on most. It wears slowly enough that you adjust to it without noticing, until the day it is genuinely stiff, or the wheel turns and the engine does not, and that day is a bad one to be discovering the difference between a cable and a hydraulic system.

Which steering does your boat have?

Three systems cover almost every boat on the water.

Mechanical cable steering is the standard on tinnies, runabouts and most outboard boats under about six metres. The wheel turns a helm unit which pushes and pulls a cable, and the cable end moves the engine. It is simple and cheap, and it is the one that seizes.

Hydraulic steering is a pump at the helm, a cylinder at the engine and two hoses between them. Turning the wheel pumps fluid into one side of the cylinder and the engine moves. It is the normal fit on bigger outboards and on most sterndrive and cabin boats, because it is light to turn regardless of engine size and it holds the engine where you put it.

Power-assisted and electric steering appear on large outboards and newer boats, and they are mostly dealer territory.

Cable steering: what wears and how it tells you

The cable's weak point is the far end, where the steel inner rod slides in a tube through the engine's tilt bracket. That tube is under the splash well, permanently damp, and it is where salt gets in and stays. The rod corrodes, the corrosion binds it in the tube, and the steering goes from smooth to notchy to stiff to seized, usually over a couple of seasons and usually without anyone noticing until it is stiff. A seized cable in a tilt tube is a genuinely difficult thing to get out, which is why the maintenance matters.

• Grease the tilt tube at the fitting most engines carry for the purpose, two or three times a season and always before winter. This alone prevents most cable failures.
• Stiffness that is worse at one end of the travel is corrosion in the tube. Stiffness that is even all the way across is the cable itself, or the helm.
• Play at the wheel before the engine responds is a worn helm unit or a loose cable connection at the engine.
• A cable is replaced, not repaired. The inner cannot be serviced, and a cable that has started to bind will finish the job.

Measure the old cable before you order, because they are sold by length. Helms, cables and the fittings are in marine steering systems, and the throttle and shift cables that usually want replacing at the same time are in marine control cables. On a single-cable system the engine's own steering torque pulls to one side; the trim tab anode under the anti-ventilation plate is there to cancel it, and it is worth adjusting before assuming the steering is at fault.

Hydraulic steering: what wears and how it tells you

Hydraulic steering does not seize. It leaks, and it takes in air.

• The wheel turns further than it used to before the engine moves, or the number of turns lock-to-lock has grown. That is air in the system, or a helm pump losing its internal seal.
• The engine will not hold position under load and creeps back. Cylinder seals, or a bypass in the helm.
• Fluid on the cylinder rod or at the helm. A seal has gone. A weep today is a failure next season.
• A soft, spongy wheel means air. The system has to be bled properly, from the cylinder end, which is a two-person job and one that is easy to do badly.

Use the fluid the maker specifies, keep the helm reservoir topped up, and rinse the cylinder rod with fresh water after salt trips so that dried salt is not dragged through the seal every time the wheel turns. Seal kits, hoses and complete cylinders and helms are in the SEAFirst hydraulic steering range and the general steering collection above.

Sterndrives: the steering seal

A sterndrive has one more steering component: the steering arm passes through the transom assembly, and the seal around it is in the water. When it fails, the symptom is water in the bilge with no obvious source, and on a MerCruiser it is common enough that it has become a job in its own right — the transom shield comes off, the seal and the arm are inspected, and the shield is machined or reconditioned as needed. That work is described under MerCruiser transom shield repairs. If a sterndrive boat is taking on water and the bellows have been ruled out, this is the next place to look.

Why it is not a job to leave

A car that loses its steering is at least on the ground. A boat that loses steering at planing speed has nothing to slow it down and no way to point it, and a seized cable at the wrong moment is exactly how boats end up on the rocks at the harbour entrance. Check it in the driveway: full lock to full lock, feel for stiffness, notchiness, play or noise, and look at the cylinder and the tilt tube for leaks and corrosion. If it is not smooth, it is not right.

We replace cable and hydraulic steering, bleed hydraulic systems, and do the sterndrive steering seal and transom work through the Kadina workshop as part of engine and drive unit rebuilds and general servicing. Ring 0412 532 984 if the wheel has started to feel different, because that is the cheapest point at which to fix it.