Steering Cable Replacement: Measuring For A Perfect Fit

When it comes to replacing your boat's steering cable, it's important to get the correct measurement to ensure your craft handles as it should. There are two types of cables on the market: Rotary steering cables and Rack and Pinion steering cables. The easiest way to measure for a replacement is to use the hot-stamped numbers on the cable's jacketing, but this only works if you're using the same brand and type of cable. If you're switching to a different type of cable, you'll need to take three measurements: the distance from the centre line of the wheel to the gunwale or deck, the distance from the dash to the transom, and the distance from the gunwale to the centre line of the cable connection at the centred tiller. With these measurements, you can use a formula to calculate the correct cable length.

Rotary vs rack steering cables

When it comes to replacing your boat's steering cable, it is important to know the differences between the two main types of steering cables: the Rotary steering cable and the Rack and Pinion steering cable.

Rotary Steering Cable

The rotary steering system is a type of mechanical steering that uses a round gear for the cable to turn around as you turn the wheel. There are two types of rotary helms: the reduction gear type and the planetary gear type. The reduction gear type is the original rotary design and is considered more efficient due to having fewer gears. However, it requires more space behind the dashboard. The planetary gear type, on the other hand, takes up less space and is recommended for boats with small dashboards. It uses four or more gears, which results in more accumulated backlash or "slop".

Rack and Pinion Steering Cable

The rack and pinion steering system is also a type of mechanical steering, and it is known for its precision. It uses a pinion gear that engages with a rack gear in a tubular housing. While it is the most efficient mechanical system for moving the cable, its drawback is that it requires a long rack housing, which may not fit behind many dashboards. Rack helms also have less mounting flexibility compared to rotary helms.

Measuring for Replacement

When it comes to measuring for a replacement steering cable, it is recommended to remove and measure your old cable before ordering a new one. If that is not possible, you will need to take three measurements: the distance from the centerline of the wheel to the gunwale or deck (measurement A), the distance from the dash to the transom (measurement B), and the distance from the gunwale to the centerline of the cable connection at the centred tiller (measurement C).

For installations through the engine tilt tube, the formula for calculating the cable length is: A + B + C + 6" = cable length (rounded up to the nearest foot). For installations mounted to the transom or splashwell, the formula is: A + B + C - 6" = cable length (rounded up to the nearest foot).

Other Considerations

When replacing your boat's steering cable, it is generally recommended to replace it with the same type of cable that was originally installed. This ensures that your boat handles as it was designed to. Additionally, it is important to identify the type of cable by looking for markings on the jacket and lettering on the helm. It is also worth noting that repair parts for mechanical steering helms, cables, and engine connection kits are not available individually for safety reasons, so these components must be replaced as units.

How to identify your cable type

When it comes to identifying your boat's steering cable type, there are a few key approaches to consider. Firstly, it is important to determine whether your boat utilises a rotary steering cable or a rack and pinion steering cable. Identifying the correct type is essential to ensure proper functionality and handling.

One straightforward method to identify the cable type is to examine the hot-stamped numbers or markings on the cable's jacketing. These markings can provide valuable information about both the type and size of the cable. However, this approach only works if you intend to use the same brand and type of cable as the existing one.

If you are unable to identify the cable type through the jacketing markings, an alternative approach is to measure the cable length. This involves taking measurements along the intended cable routing. Standard measurements to consider include the distance from the gunwale to the centre line of the cable connection (A), the length along the gunwale (B), and the distance from the centre line of the wheel to the gunwale (C). By summing these measurements and adding an additional 6 inches, you can determine the total cable length.

It is worth noting that certain steering systems, such as the through-the-engine-tilt-tube system, are more common than others. Additionally, it is generally recommended to replace the steering cable with the same type that was originally installed. This ensures that your boat handles consistently and maintains its original performance characteristics.

In summary, identifying your boat's steering cable type involves examining markings on the cable jacketing, measuring cable lengths, and considering common steering system types. By following these steps, you can ensure that you select the appropriate replacement cable for your boat.

Measuring for a new cable

Firstly, it's important to note that there are two types of cables on the market: Rotary Steering Cable and Rack and Pinion Steering Cable. The easiest way to ensure you get the correct length is to check the hot-stamped numbers on the cable's jacketing. However, this only works if you are using the same brand and type of cable.

If you are using a different brand or type of cable, you will need to take measurements. The first step is to identify the type of cable from the markings on the plastic coating. This will give you an idea of the type and size of the cable. Some cables are measured in feet, while others are measured in meters.

The next step is to take the necessary measurements. For rack or rotary cables, you will need three measurements:

• Measure A: The distance from the center line of the wheel to the gunwale or deck (if a downward mount).
• Measure B: The distance from the dash to the transom.
• Measure C: The distance from the gunwale to the center line of the cable connection at the centered tiller.

Using these measurements, you can calculate the length of the cable using the following formulae:

For installations through the engine tilt tube: A + B + C + 6 = the cable length (round up for sizing)

For installations mounted to the transom, splashwell, or stringer: A + B + C - 6 = the cable length (round up for sizing)

Alternatively, you can use the following formulae, which take into account the type of cable:

For Rotary Steering Cable: Measure the plastic cable jacket, add 18 inches, and round up to the next foot.

For Rack Steering Cable: Measure the plastic cable jacket, add 30 inches, and round up to the next foot.

By following these steps and using the provided formulae, you can ensure that you have the correct measurements for your new boat steering cable.

Replacing an existing cable

When replacing an existing boat steering cable, the first step is to identify the type of cable and its size. Look for markings, numbers, or letters on the plastic coating or cable jacket. These will indicate the type of cable (rack, rotary, or hydraulic) and may also indicate its size.

If you're unable to identify the type of cable or take measurements from the markings, you can follow these steps:

Rotary Steering Cable Replacement:

Measure the plastic cable jacket (“Y” dimension) in inches, add 18”, and round up to the next foot. Order a replacement cable of this length.

Rack Steering Cable Replacement:

Measure the plastic cable jacket (“Y” dimension) in inches, add 30”, and round up to the next foot. Order a replacement cable of this length.

JBS Jet Boat Cable Replacement:

Measure the old cable from tip to tip. Round up to the next foot if needed, and order a replacement cable of this length.

It is recommended to replace the entire steering system if your current system is over 10 years old. Additionally, always replace your boat steering cable with the same type that was originally installed to ensure your craft handles as intended.

Rounding up to the next foot

When measuring for a replacement boat steering cable, it is important to get the correct length. There are two types of cables on the market: Rotary steering cables and Rack and Pinion Steering Cables. The easiest way to ensure the correct length is to use the hot-stamped numbers on the cable's jacketing. However, this only works if using the same brand and type of cable.

If you are using a different brand or type of cable, you will need to take measurements. Measure the distance from the centre line of the wheel to the gunwale or deck (if a downward mount). This is measurement A. Then, measure the distance from the dash to the transom. This is measurement B. Finally, measure the distance from the gunwale to the centre line of the cable connection at the centred tiller. This is measurement C.

The equation for installations through the engine tilt tube is: A + B + C + 6 = the cable length. For sizing, always round up to the next full foot. For example, if your total measurement is 138", this would be rounded up to 12 feet.

The equation for installations mounted to the transom or the splashwell is: A + B + C - 6 = the cable length. Again, for sizing, always round up to the next full foot.

It is important to replace your boat steering cable with the same type that was originally installed. Rack steering should be replaced with rack, hydraulic with hydraulic, and rotary with rotary. This way, your boat will continue to handle as it did originally.

Frequently asked questions