Measuring Outboard Shaft Length

==How to Measure an Outboard Shaft Length==

Measuring the outboard motor shaft length is essential in choosing the suitable motor for a boat.

===Measuring the Shaft Length===
To measure the shaft length, you will need a tape measure or another tool for taking measurements, a pen and paper or a digital device to record the measurements. The process involves three simple steps:

1. Measure the vertical distance between the top of the transom and the boat's waterline. This measurement represents the vertical distance.
2. Add 16 inches to the vertical distance obtained in step 1. This calculation provides the minimum shaft length required for the outboard motor.
3. If you plan to navigate rough waters, adding an extra 4-6 inches to the minimum shaft length obtained in Step 2 is recommended.

===Instructions===
Follow these instructions to measure the outboard shaft length accurately:

1. Locate the top of the transom and the lowest point of the boat hull. Measure the distance between these two points. This measurement represents the transom height.
2. Find the radius of the propeller. You can refer to the owner's manual of the outboard motor or search for a diagram online using the motor's name, model, and year. Alternatively, you can measure the propeller radius yourself. Add the transom height obtained in Step 1 to the propeller radius. The resulting value represents the minimum shaft length required for your boat.
3. To determine the ideal shaft length, add 10 cm (or the equivalent in inches) to the value obtained in Step 2.

===Examples===
To provide a clear understanding of the calculation process, let's consider the following examples:

Example 1:
Transom height: 20 inches
Propeller radius: 5 inches

Minimum shaft length: 20 inches + 5 inches = 25 inches
Ideal shaft length: 20 inches + 5 inches + 4 inches = 29 inches

Example 2:
Transom height: 18 inches
Propeller radius: 6 inches

Minimum shaft length: 18 inches + 6 inches = 24 inches
Ideal shaft length: 18 inches + 6 inches + 4 inches = 28 inches

Once you have determined the ideal shaft length for your boat, you can proceed with your purchase decision and install the outboard motor accordingly.

==How to Measure Transom Height?==
Ensuring that the outboard motor is mounted at the correct height is crucial for optimal performance and safety. Follow these steps to measure the transom height accurately:

1. Place your boat on a flat surface with the transom facing up.
2. Identify the transom center, the vertical surface at the back of the boat where the outboard motor will be mounted.
3. Measure the distance from the transom center to the bottom of the boat. This measurement represents the transom height.

By measuring the transom height and following the steps outlined above, you can determine your boat's appropriate outboard motor shaft length.

==Also See:==
* [[Hitchhiking the Oceans as Sailing Crew|Hitchhike the oceans as sailing crew]] - See where the cruising yachts are at different times of the year as they sail around the world.
* [[Navigation]]
* 

==Links==
* [https://tohatsu.com.au/wp-content/uploads/2022/02/Transom-Length_0.pdf] pdf download
* [https://www.navigatorboat.com/how-to-measure-an-outboard-shaft-length/ How to Measure an Outboard Shaft Length] - Guide
* [https://www.youtube.com/watch?v=gATD8c4mAsI&ab_channel=HideaOutboardMotors] Youtube video instruction
* 

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[[Category:General Cruising]]