How a Steering Cable Works

Steering cable is often employed as a method of steering medium-sized boats with outboard motors. Small boats tare usually steered by a tiller, while large boats typically have hydraulically assisted power steering.

Helical Gear

Steering cable systems are usually rotary or rack-and-pinion. In either case, a helically wound coil, or spring, is wrapped around the inner core of the cable. The coil meshes with a gear on the steering head.

Rotary

In a rotary system, when the steering wheel is turned one way or the other, a gear pulls or pushes on the coil. This, in turn, effectively lengthens or shortens the length of the steering cable at the point where it attaches to the outboard motor, causing the boat to turn one way or the other.

Rack-and-Pinion

Rack-and-pinion steering cable systems similarly pull or push on a pinion gear on the steering shaft that drives a linear gear, or rack. The diameter of the pinion gear and its number of teeth determine the number of turns of the steering wheel required to complete one full stroke of the steering cable.

References

• "Outboard Engines: Maintenance, Troubleshooting, and Repair"; Edwin R. Sherman; 2008
• "How Boat Things Work"; Charlie Wing; 2003