What is a Sailboat Rudder?

What is a Sailboat Rudder? | Life of Sailing

Written by

Daniel Wade

A sailboat rudder steers the boat. A rudder is a hinged fin or blade mounted on the stern of the vessel that turns side to side, and it's controlled by a tiller or a helm.

A rudder is one of the primary controls of a sailboat. When the boat moves forward through the water, the rudder causes friction on one side and changes the direction of the boat. Rudders are controlled by moving a tiller side to side or by a helm and a complex linkage system. Rudders are delicate and sometimes flush with and protected by the keel.

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Identifying the Rudder

Rudders are connected to the sailboat using a hinge or a shaft. The rudder is always located in the water behind the boat, but some rudders have part of their structure exposed above the waterline. Rudders that aren't visible above the waterline are usually underneath the stern and controlled by a vertical shaft that descends through the bottom of the boat.

Rudder Design

Rudder design varies widely between boats. Some vessels have large, ornate rudders that are exposed above the waterline. Large rudders are common on catboats, canoe yawls, and other traditional designs.

Many modern boats use small, blade-like rudders that are hidden from view. The size of a rudder doesn't necessarily correlate with its effectiveness, but an improperly sized rudder can cause significant issues.

How Does a Sailboat Rudder Work?

Sailboat rudders are simple devices. Rudders are essentially deflectors, as they deflect water to port or starboard as the boat moves along. When the rudder is amidships or in the middle and aligned with the keel, the boat goes straight. Rudders also help keep the boat on a straight track as they increase the area of water moving down the length of the boat.

Rudders only work when the boat is moving. If there's no moving water to deflect, the rudder can do little to direct the vessel. Rudders also don't work when the boat is blown sideways. Maneuvering is only possible when the boat is moving forward.

Can a Sailboat Rudder Steer in Reverse?

But what about moving in reverse? Rudders can be used to steer the boat in reverse, but they're significantly less effective when pushed backward through the water. The distance required to make a turn in reverse is usually much higher than when moving forward, and steering input is less precise. In some cases, sailboat rudders can break off when moving too quickly in reverse.

Sailboat Steering Characteristics

Sailboats steer much differently than cars, and there aren't any brakes to slow down with. Sailboats tend to steer from the middle; picture a fan blade spinning slowly on a motor, and you'll get the picture. As a result, steering too aggressively in tight quarters can cause your bow or stern to hit something that's beside you.

Speed is generally helpful for steering, especially when you want to make precise movements quickly. However, speed is a double-edged sword, as slight rudder movement at speed can dramatically and rapidly alter the course of the boat. But remember, you can't steer without moving forward.

Tiller Steering

Sailboat rudders are often controlled by a tiller. Tillers are a long rod connected to the rudder. Sailors move the rod side to side from the cockpit to turn the rudder directly. Tillers are the simplest form or rudder control, and they're highly reliable. Tillers point in the opposite direction that the boat will travel.

Tiller steering is found most often on small boats. This is because the forces involved in steering boats of greater size can be too difficult to manage with a tiller. That said, there are some relatively large boats with cockpit configurations that allow for the use of a tiller. Sailboats with tillers range in size between 10 feet and 30 feet.

Benefits of a Tiller

Tillers have numerous benefits. Tillers offer precise control of the boat because they connect the rudder directly to the person steering the boat. Additionally, tillers are extremely simple and robust. Many blue water sailors prefer tiller steering, as it's difficult to break and easy to repair.

Over the years, sailors have developed many creative ways to make tillers more useful. Many boats feature tiller extensions that allow the sailor to steer from further away. Tillers also respond much faster than helms, which is great for racing and pushing the limits of the boat.

Tiller Self-Steering

Bluewater sailors developed an extremely useful way to multitask onboard a tiller-equipped sailboat. Self-steering is possible on vessels with a tiller, and no electronics or complex machines are necessary. Self-steering involves connecting the jib sheet to a series of pulleys and opposing bungee cord (or surgical tubing).

As the tension on the jib increases, it'll tighten the jib sheet and pull the tiller and change the course of the boat. The opposite is also true. This keeps the boat at the right angle to the wind and is useful for solo travel. GPS-guided self-steering equipment is also available for tiller-equipped sailboats, and it's relatively easy to install.

Helm Steering

A helm is essentially a large nautical steering wheel. Steering a boat with a helm is somewhat similar to driving a car, as the boat moves in the direction that you steer (unlike a tiller, which moves in the opposite direction). Sailboats equipped with tillers are usually larger. Some larger sailboats have two helms placed side-by-side in the cockpit.

The helm consists of a steering wheel and a pedestal which is mounted to the deck. Helm pedestals often feature a marine compass to make navigation possible from one location. Engine controls are often located nearby as well. Sailboat helms are often large in diameter, sometimes 30 inches or more. Large wheels make steering easy and precise.

Helm-equipped sailboats are generally 30-feet long and larger. Tillers are excellent for large boats, as they enable precise movement and require little effort to use. This is especially important at speed when the force of water rushing by a large rudder can be too difficult to overcome with a tiller.

The helm is connected to the rudder mechanically or hydraulically. Some high-end sailboats incorporate power steering, but this is unusual on most consumer vessels. Mechanical helm linkage typically utilizes a cable (or multiple cables and pulleys) that stretches from the helm to the rudder.

Hydraulic Rudder Control

Most sailboat helms are hydraulic. These helms use pressurized hydraulic fluid and small diameter lines to replicate the wheel movements at the rudder. Hydraulic systems often include a fluid reservoir and a pressure cylinder, along with mechanical parts to transfer the force at the wheel and the rudder.

Rudder Maintenance

Rudder maintenance is fairly simple and should be performed regularly. As with the hull, rudders are an ideal habitat for all kinds of unwelcome marine life. Within a year or less, your rudder can be completely encapsulated in barnacles, plants, and other organisms. Marine growth will negatively impact your speed and steering, so it must be scraped off regularly.

Maintaining the steering system is also essential. Tillers are relatively easy to maintain, as they use very few moving parts. Look for grease fittings, and make sure your tiller and rudder are fastened tightly. Helms are more complex, and the hydraulic system should be inspected, repaired, and topped off if necessary.

What to Do if the Rudder is Damaged

Rudder damage is a sailor's worst nightmare, and it's akin to a hole in the hull or losing a mast. So what should you do if your rudder gets damaged or breaks off? First, call for help! But if help isn't available, there are a few makeshift ways to steer the boat without the rudder.

If you have an outboard motor, use it to steer. If not, then a run-of-the-mill rowboat oar makes an excellent rudder substitute. Simply lash the oar to the back of the boat with the end in the water, and use it like a tiller. It's not ideal, but it worked for the Romans, and it should work for you. Some sailors have fashioned makeshift rudders from interior cabinet doors, hatches, scrap metal, and whatever else is on hand.

Losing a rudder is a worst-case-scenario, and it doesn't often happen when sailors keep up with maintenance and stay away from dangerous water. Preventative maintenance and proper navigation are the best ways to keep your rudder in good shape. 

What is a Sailboat Rudder?
Daniel Wade

Daniel Wade

I've personally had thousands of questions about sailing and sailboats over the years. As I learn and experience sailing, and the community, I share the answers that work and make sense to me, here on Life of Sailing.

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