Recently, during a night passage between Hawaii and Guam, a boat’s steering failed. Moments later, the engine stopped. A quick check of the bilges proved there was no water coming in, so the crew shined spotlights off the stern. They saw the prop and rudder fouled in a polypropylene fishing net.

Fortunately, a variety of cutting tools were aboard, as well as diving equipment. Once the sun came up, the net was cleared, allowing the boat to resume its course safely.

There are three boating fundamentals: The seawater must be kept on the outside, the boat must have a method of propulsion, and the boat must have the ability to be steered.

Today, we’ll concentrate on the steerage equipment that lets us choose our path on the sea.

And a Star to Steer Her By

The simplest, permanently mounted way to steer a boat is with an outboard rudder and a tiller. The rudder is usually hung with substantial metal pintles and gudgeons that are secured to the transom. Push the tiller one way, and the boat goes the other.

In an effort to clear the cockpit, facilitate hydrodynamic efficiency and reduce an outboard rudder’s vulnerability to damage from strikes, designers moved the rudders below the boat, and added bearings and stuffing boxes to support the rudderpost and keep the seawater out. Keeled boats may also add skegs to help support the rudder at the bottom and to reduce the vulnerability to hitting objects in the water. Naval architects discovered that adding a small amount of rudder area forward of the rudderpost eased steering loads and improved steering. On quicker boats, there is a relationship between having the rudder small enough to reduce drag but still large enough to do its job when slowing down and maneuvering to a dock.

Rudders can be made of wood or metal, or they can have a metal armature shaped with foam and wrapped in fiberglass. Stocks can be bronze, stainless steel or composite and carbon fiber with different benefits for different applications. The rudder must be supported against twisting and side loads. Achieving this may be as simple as mounting the stock in a tube, or combining bearings, stuffing boxes or skeg support. Articulated rudders have flaps on their after edges that turn at a quicker rate than the main rudder. This can multiply the steering action and really help with slow-speed maneuvering.

If a rudder shaft penetrates the hull, and if the opening is below the waterline, then some sort of rudder shaft seal is required. This can be a simple bronze stuffing box with packing or a dripless style with a lip seal. Because the rudder shaft spins relatively slowly, it doesn’t suffer from heat-related problems like a prop shaft seal does. Stagnant, low-oxygen water can sit inside the rudder tube and cause crevice corrosion in stainless steels. Pitting in the shaft can cause sealing issues for either style of gland. The lesson is to use your boat regularly, and to keep the water fresh and replenished.

Inboard rudders require a stuffing box that can help with support. Conventional rudder stuffing boxes with waxed flax packing are often designed to contain only one or two wraps of packing. Dripless boxes are also available, although their maintenance schedule should not be neglected. All shaft glands require periodic inspection and occasional disassembly to confirm that no damage to the rudder shaft is occurring.

Liquid Actuation

How hydraulics work remains a mystery to many boat owners. In the simplest sense, hydraulic oil is incompressible. The hose and fittings of the system must be rated to handle more pressures than the oil can be compressed, and the oil must be perfectly clean. There is a pump (the helm) on one side and a ram on the other. The pump pushes the oil into one side of the ram piston, and this moves the shaft (and the tiller and rudder). Switch directions at the pump, and the fluid pushes on the other side of the piston. Interestingly, the helm pump can also be configured to multiply the force, making steering easier. Many pumps let you choose: You can have more turns, easier force and slower steering, or you can have fewer turns, more force and quicker steering.

The trick comes in understanding the loads involved on the rudder so the ram, hydraulic lines, fittings and steering pump will be able to handle them without failure. If a substantial leak occurs—through a cracked fitting, leaking hose or failed seal—all steering can be lost.

Fortunately, some stellar companies sell high-quality steering gear and can help recommend replacement items. From a structural sense, the ram is carrying most of the load from the rudder, so it should be properly sized and strongly attached to a substantial shelf that is robustly connected to the hull.

There are different ways to deal with keeping air out of the hydraulic system. One is the use of gravity. Typically, the helm pump is the highest point in the system, so it becomes the fill point. Hydraulic oil is added and then pushed through the system (via the helm pump or a special purging pump tool) until all the air is removed. If a second helm is added, at a flybridge, for instance, this becomes the fill point. Adding a remote reservoir for the highest helm can give you a reserve of fluid as well as a good oil-level visual.

Another type of system doesn’t rely solely on gravity and instead utilizes a pressurized pot as the fill point, which also keeps the system air-free.

The size of the steering wheel affects how much effort it takes to turn the rudder. A larger wheel has more leverage and is easier to turn. This is true of cable-controlled systems as well as hydraulic systems. While you might not expect it, hydraulic oil does suffer frictional loss, so keep hose bends gentle and keep the 90-degree elbows to a minimum. Too small of a hose can also add frictional loss. Hoses and fittings should be rated up to 1,000 psi. Brass or stainless steel fittings are recommended, not bronze. Never use Teflon tape to seal fittings, or you can contaminate the system with Teflon strings.

Hydraulic fluid can be carried in a metal tube or in pressure-rated, wire-
reinforced hose, typically with crimped or mechanical flare fittings. Smaller boats can use specialty plastic hose manufactured for that purpose. There is a lot of chatter about what fluid to use, but the best answer is whatever the manufacturer of the pump and ram recommends. Other fluids will get you home in a pinch, but the system should be flushed and replaced with the correct fluid as soon as practical. All fluid should be periodically checked to ensure that it is not burnt or discolored with debris.

Some engines can supply a power assist to the hydraulic steering, a setup that can greatly reduce the effort to turn the wheel. The concept is ubiquitous on cars and trucks. The power assist does rob a small amount of power from the engine, and it adds some complexity while requiring more frequent oil replacement. Electric assist is also available for some systems that use a DC-powered pump to help push the hydraulic fluid.

Steer-by-Wire

Electric steering wheels that control a ram at the stern are becoming more popular. Years of using reliable autopilots to perform the same function have lessened fears about lacking a direct connection with cables or hydraulics between the wheel and rudder. The American Boat and Yacht Council has standards regarding the systems and their installations. In regard to the system’s strength and speed, the ABYC standards note that the steering system shall be capable of completing its full range of travel at a minimum of 18 degrees per second against a minimum of 750 pounds linear force or 500 pound-feet of opposing torque. The steering system shall begin to respond to the input command within 0.2 seconds. This ensures that the system is strong, quick and reliable.

The benefits are many. Easy integration with autopilots, customizable lock-to-lock and adjustable effort-to-turn can greatly reduce steering fatigue. Some systems can have multiple modes for easier docking or less steering wheel movement while underway. Even with conventional steering, autopilot electronics have become increasingly sophisticated and reliable. More and more people use them for a majority of the steering. Autopilots can be fine-tuned for the sea state and can often steer a straighter and more accurate course than a human, although they should never take the place of a proper lookout.

Rarely does a year go by without a service call regarding a malfunctioning autopilot in which the solution is to remove the toolbox, spare anchor or other metal object located next to the electronic compass for the system. Such items can cause the autopilot to steer in an unpredictable manner. Be sure you know where your autopilot compass is located, and place a label on both sides of the bulkhead where it’s mounted. Otherwise, a well-intentioned guest can cause an issue.

Electric systems (and many autopilots) can also integrate follow-up levers and non-follow-up levers to facilitate docking or steering as alternatives to a wheel. A non-follow-up lever moves the rudder and is spring-loaded back to center when released. Follow-up levers are not spring-loaded, and the rudder stays in the position where it’s set until the lever is moved again. Most autopilot systems can be fitted with joysticks, wired or wireless remotes as well.

Dead Helms

All boats should have some alternative method of steering if the main system fails. An emergency tiller that can be fitted to the rudder head is one answer.

For the system to work properly, some questions need to be answered. How much force does it take to steer? Can you see a compass or chartplotter while the tiller is being used? Are you exposed to the elements? Can the tiller be set up with blocks added to pad eyes on the toerail, so lines can be reeved to reach the pilothouse? Perhaps a whipstaff arrangement or a drum temporarily rigged to the helm wheel to wind the line and give some mechanical advantage may be in order.

Note that most hydraulic systems require bypass valves installed in the hoses close to the ram so the person using the emergency tiller is not also trying to move all the fluid in the system. Alternatively, the ram could be disconnected from the normal tiller and tied out of the way.

Other considerations might include having spares of key parts of the steering system so you might not have to resort to the emergency tiller. At a minimum, spare fluid for hydraulic units should be aboard, and the captain should know how to fill the system. Perhaps some spare hose or pipe and extra fittings including plugs and caps would be helpful. Spare rams or separate steering and autopilot rams could also get you out of trouble. For boats with cable systems, you may want a length of cable and some extra cable clamps aboard.

The trick is to test any emergency system while underway by choosing a calm day close to home. That way, you will know what to expect, and you can make adjustments before trying to fix a problem on a dark, stormy night, far from help. A careful inspection for leaks, damage or wear will let you concentrate on where you’ll go instead of worrying about how you’ll get there.  

This article was originally published in the March 2024 issue.