Hydraulic Vs Mechanical Boat Steering & A Guide to Steering Systems (updated June 2022)

Most boats have either mechanical or hydraulic steering systems. Choosing the right steering system for your boat depends on the size of the boat and the type (and size) of the motor. You may be looking at upgrading your boat’s steering from a tiller steer outboard to mechanical steering, or from mechanical to hydraulic boat steering.

This post is intended to give you a good overview of boat steering systems to help you choose the right steering for your boat. It also includes some helpful tips on maintenance and repairs.  It is general information only however, and is not intended as a replacement for professional advice from a qualified marine mechanic.  Always seek advice from a qualified tradesperson in this field or hire them to carry out the work for you if you are unsure about anything.

What is Hydraulic Steering & How Does it Work?

On boats, hydraulic steering is usually used with mid to high horsepower outboard motors.

Hydraulic steering systems use a lightweight hydraulic hose to control the steering. This offers larger or high-powered vessels a smooth, lightweight feel when turning the steering wheel. With fewer metal parts than a mechanical system, hydraulic steering has the benefit of being more resistant to corrosion. Hydraulic systems can deal with all torque conditions and may only require fingertip effort.   

There are two main parts to hydraulic boat systems – the helm and the cylinder.

Helm – made of a hydraulic pump and valves. When the steering wheel is turned the pump is activated, and a swash plate presses on small piston pumps. The helm is responsible for converting the rotating motion of the steering wheel into a push-pull action on the cable. This cable directs the rudder to move left or right to steer the boat in the skipper’s desired direction. Most helms are rotary and use gears to move the rudder.

Cylinder – moves when fluid is pumped from the helm after the wheel is turned. The cylinder acts between two points on the outboard and doesn’t exert any force on the hull or deck. The cylinder is made up of a ram, bored cylinder and hardware.

Hose –  hydraulic hose carries fluid from the helm to the cylinder and back.

What is Mechanical Steering & How Does it Work?

Mechanical steering systems, also known as manual or non-power steering, are most commonly used in smaller boats.

Mechanical steering uses push-pull cables which connect the steering wheel and helm at the front of the boat with the outboard motor. This system provides good handling performance and safe operation for smaller boats up to 10 metres in length.

Some owners of small boats that use a tiller arm to steer the boat may want to upgrade to mechanical steering to allow them to use a steering wheel, sit closer to the front and steer with less physical force.

There are three main parts in a mechanical boat steering system – the helm (rotary or rack and pinion), steering cable, plus the connection kit (if required).

Rotary Helm – the rotary helm is housed behind the instrument panel and converts the steering wheel movements into the push-pull action on the cable. The helm has a round gear which holds the turning cable. Different helms cause a different number of lock-to-lock steering wheel turns (the number of times it takes a skipper to get a fully-turned wheel on one side fully turned to the other side). More wheel turns means less effort to turn the boat.  

The two types of rotary helms have the following gears:

• Reduction Gear Type – A large round assembly of dials and gauges behind the dash that provides the skipper with information on engine speed, performance, fuel usage and trim tab location. The system may be analogue or digital but due to their size, may not fit in the dash of small boats.    
• Planetary Gear Type – This system uses three or more gears that mesh with a drum to move a cable. While this system is much smaller than the reduction system, it has more wear points.  

Rack and Pinion Helm – Fitted on the steering shaft, the pinion gear engages a rack gear in a tubular housing. The rack and pinion helms offer less friction than a rotary helm and are an efficient system for moving the cable. However, they are wide and not suitable for many dashboards because of their larger size. They are ideal for boats with low dash panels that don’t have enough vertical clearance for a rotary helm. (Boat Accessories Australia does not stock this helm type)

Steering Cable – The push-pull cable that moves the rudder or engine in response to the steering wheel being turned. Single-cable steering is fine for boats with a motor of 130 hp or less. More powerful engines such as a V6 motor on a high-performance boat should use a dual-cable steering system. Two helms are stacked on the same steering wheel shaft to distribute the load across two cables. With one cable under tension and the other in compression, steering slop is minimised, offering better feel and control.  

Engine Connection Kit – Hardware that connects the engine or tiller with the steering cable

Differences Between Hydraulic & Mechanical Steering Systems

The decision on which steering system you choose will depend mainly on the requirements of your boat including its size, the engine trim and propeller.   

Boat Size

A hydraulic steering system is recommended for larger boats 10 metres and above in length and those moving at high speeds. The torque (or force) of a large outboard motor means it can be difficult to bring out of a turn or veer sharply from heading straight with mechanical steering.

A mechanical steering system is suitable for boats under 10 metres in length. Mechanical steering shouldn’t be used on boats that have engines fitted that exceed the boat’s recommended maximum horsepower.

Cost of Steering Systems

Mechanical systems are cheaper, but recently hydraulic systems suitable for smaller boats have become less expensive. This means more people are now keen to upgrade their boat with a hydraulic steering system. This trend is expected to continue, and it will be more common for boats with outboard motors of 50hp or less to use hydraulic steering in the future.

Maintenance

All steering systems need inspection and maintenance but there is less maintenance required for a hydraulic steering system over a mechanical one.  Even so, despite being more reliable your hydraulic system still needs regular maintenance. For further reading, check out these tips on how to install and maintain a hydraulic steering system.

Mounting of Boat Motor

Whichever steering you use, ensure your boat’s motor is mounted correctly as per the boat and engine manufacturers’ instructions. The position of the motor can affect steering load and boat handling.  

Maintenance of Your Boat’s Mechanical Steering System

Maintenance of your steering system should be completed at least twice per year to keep it in working order and ensure smooth, safe operation. Corrosion of the steering cable can cause stiff movements, seizure, even total loss of steering control. Consult your manufacturers’ instructions before beginning any maintenance.

Maintenance Steps:

1. Inspect the steering system: look at the helm and engine end checking for any loose or corroded parts. Check the cable’s plastic jacket for any cracks, cuts, or signs of corrosion. If you locate any damage, find the part number to replace the cable completely, don’t try to repair it.

2. Maintenance of the steering cable: remove the steering cable’s telescopic ram from the tilt tube by loosening the lock nut at the end of the jacket. You’ll also need to undo the locking nut from the steering cable and drag link. Pull the cable by its jacket to free the ram of the tilt support tube. Clean the inside diameter of the tilt support tube and remove any corrosion in the tilt tube using a wire brush. Using a water resistant marine grease, lubricate the tilt tube. Clean the steering cable’s telescoping ram using a wire brush and wipe. Use the grease to lubricate the sliding parts of the telescopic ram.

3. Reassemble parts making sure everything is tight, and there is no excessive free play in the moving parts.       

4. If a boat is not going to be used for a season, remove the cable output from the tube and store separately.

Replacing Cable Steering

It’s recommended that you completely replace the steering cable if it is damaged. The cable must be installed without any kinks, sharp bends or obstructions to ensure the skipper can manoeuvre the boat at any speed. Multiple bends in the cable can cause backlash and inefficient steering so use as few bends as possible when routing the cable.

Test for ease of steering through the full range, lock to lock, to ensure the new cable is working before taking the boat out on the water.

For more information or to view the parts available, see our mechanical steering range.

Upgrading Your Boat’s Steering System

Some manufacturers will tell you that steering should be replaced with the same type. So, if your boat has a mechanical steering system, they recommend you stay with a mechanical system to ensure the boat continues to handle as it was designed.

However, in most instances upgrading to a new system isn’t a problem. Just be aware that the boat will steer differently so you will need some time to get used to the new steering before you tackle any difficult sea conditions.    

Changing from Tiller to Mechanical Steering - Factors to Consider

If you're tired of having to sit at the rear of the boat using a tiller arm, a mechanical system might be the upgrade you need. However, it’s not a simple decision when you are considering changing your boat from tiller to mechanical steering. Below are some factors you should think about before making a decision.

The advantages of changing to mechanical steering include:

• No feedback – the effort required to keep steering in a straight line with a tiller can be considerable. The amount of feedback is determined by the steering system, the boat, propeller and boat’s speed.
• Less fatigue - rough conditions or steering your boat for a long time can result in a tired or sore arm.   
• Better line of sight – mechanical steering allows you to sit closer to the front of the boat and see better when steering.

The disadvantages of changing to mechanical steering include:

• Less space – a steering wheel and helm is going to take up valuable space in your boat so look at how much space you can afford to lose.
• Manoeuvrability – some boat owners report their boat is more difficult to handle after completing the upgrade to mechanical steering. Be prepared to spend time getting used to the new steering system before tackling any difficult conditions.
• Cost – buying the parts and paying for labour (if you don’t do it yourself) can be expensive.

Changing from Mechanical to Hydraulic Steering

An increasing number of boat owners are converting their mechanical to hydraulic steering every year. If you follow the manufacturer's instructions in your kit, you can install the new hydraulic steering system yourself.  But if you're not confident, it may be safer to hire a professional to do it for you.

A Note on Safety

Steering is one of the few parts on your boat that has a single point failure. Total loss of steering is possible if you don’t follow installation instructions or inspect and maintain your steering system regularly.   

Disassembly or repair will void some warranties and could cause dangerous problems with your boat’s steering so read your manual carefully before undertaking any work. Remember, some parts such as nylon nuts are single-use only. If you take them off for maintenance or service, don’t use them again as they could fail.

Whichever steering system you use, ensure your boat’s motor is mounted correctly as per the boat and engine manufacturer’s instructions. The position of the motor can impact on steering load and boat handling.

Boat Steering Kits

Buying complete mechanical steering kits makes the job easier and less risky than buying individual parts. Hydraulic steering kits for 115hp, 175hp and 300hp as well as parts are available in our online shop.  

If you need any help choosing the right steering system or part for your boat, don’t hesitate to call the team at Boat Accessories Australia on 1300 308 161 or contact us online.