Steering system roundupMar 3, 2015
In the 2015 Ocean Voyager issue, contributing editor Wayne Canning looks at steering systems and the things voyagers need to do to keep them in good working order. In the piece below, Canning outlines the types of steering systems typically used on boats.
Steering systems can range from the very simple such as a tiller mounted on the rudder head to more complex wheel systems with multiple helm stations. Of course, the more complex a system is the greater chance of something going wrong. Although there are many types of boats most steering systems fall into a few basic categories.
Tiller steering: Many smaller sailboats will have tiller steering with the tiller attached directly to the top of the rudder shaft.
Chain and wire system: Most ocean and coastal sailing boats however are fitted with wheel steering. The most common wheel steering is the chain and wire system. This is a fairly simple system consisting of a wheel with a chain sprocket on the helm shaft. This in turn drives a chain which is attached to a wire cable at each end. The cable is passed through the boat using pulleys until it reaches the quadrant which is mounted on the rudder shaft. As the wheel is turned it will pull one end of the cable and the other end follows. This then pulls the quadrant in the direction needed to turn the boat.
Cable conduit: Another common variation of this is a cable conduit system. This system uses the chain and cable but instead of the pulleys the cable is run in a flexible conduit. Conduit systems are often used when the cable runs from helm to quadrant are short as the friction of the conduit becomes greater with long runs. Sometimes a combination of the conduit and pulley system is used on longer runs such as installations on center cockpit boats. The conduit is used to get the cable through the cabin and they continued through the bilge on using pulleys.
Geared mechanical drive: An increasingly more common configuration on sailboats is the geared mechanical drive system. With a mechanical system the helm or helms are connected to the rudder through a series of chains, gears, levers, and rods that push or pull the rudder tiller arm. These are generally used when the helm is close to the rudder shaft and are often found on newer duel helm boats. The advantage of these systems is they tend to have fewer moving parts and do not have a cable to wear out and break. They do have many parts and links that can and do go wrong though and have bearings and gears that can wear.
Push/pull cable systems: More popular on vessels with smaller rudders such as small power boats and small catamarans is the push/pull cable system. This system uses a rack and pinion at the helm to push and pull on a single cable that is lead through a conduit to a tiller arm on the rudder. This type of system is better suited to lighter loads as the single cable must carry the loads in both directions of travel. Friction can also be an issue on longer runs.
Hydraulic steering systems: More common on power boats are hydraulic steering systems. These consist of a helm pump that is connected with tubing to one or more, linear rams or pistons. The ram then pushes or pulls a tiller arm depending on the direction the helm is turned. Hydraulic systems work well with multiple helm stations. These systems are fairly simple but do have some weak points that can result in steering loss. Most common failures occur when a fitting fails and the system loses fluid and pressure. Although not common, hydraulic systems are sometimes used on sailboats. The reason most sail boaters do not like these systems is the lack of rudder feedback or “feel” to the helm this is not a problem on powerboats. Hydraulic systems can also be power assist like found in cars. Power assist can be either engine driven or use an electric pump.