Garmin Trolling Motor Shaft Length Guide: Force Pro & Kraken Sizes
Measure First. Buy Once.
Measure Once and Match the Shaft With Confidence
The correct Garmin trolling motor shaft length helps keep the propeller at a dependable operating depth as bow height, load and wave conditions change. Use this guide to measure your boat and compare Force Pro and Force Kraken sizes before ordering.
Short answer
Measure vertically from the trolling-motor mounting surface at the bow to the waterline. Garmin says to add 8 inches to that measurement if you regularly operate in sizable waves. Then use the model-specific range below and confirm the exact motor in the Garmin trolling motor collection.
A shaft that is too short may allow the propeller to ventilate or lose effective bite when the bow rises in chop. A shaft that is unnecessarily long can complicate stowing, deck clearance and shallow-water use. That is why a Garmin Force shaft length should be chosen from a real measurement instead of boat length, horsepower or a photo of a similar hull.
Garmin Force Pro is available in 50- and 57-inch versions. The broader Garmin Force Kraken lineup offers 48-, 63-, 75-, 90- and 110-inch shafts, allowing buyers to cover everything from lower-freeboard applications to large coastal center consoles. Availability, color and sonar package can vary by exact model.
How to Measure for a Garmin Trolling Motor Shaft
- Put the boat in a realistic condition. Measure while the boat is floating level and carrying a typical distribution of fuel, batteries and gear whenever practical.
- Identify the mounting surface. Use the deck surface where the trolling-motor mount will sit—not the top of a bow rail or a random point on the gunwale.
- Measure vertically to the waterline. Keep the tape vertical and record the distance in inches.
- Account for normal conditions. Garmin advises adding 8 inches if the boat regularly encounters a sizable number of waves.
- Compare the result with the correct family. Force Pro and Force Kraken do not use the same shaft choices, so use the proper row in the chart below.
Why the ranges overlap
Overlapping ranges give buyers room to account for deck layout and operating conditions. If your measurement falls in an overlap, the shorter shaft may suit protected water and a lower bow, while the longer shaft can provide more margin for chop. Confirm stowed clearance and installation space before choosing the longer model.
Garmin Force Pro and Kraken Shaft Length Chart
The following ranges reproduce Garmin's published bow-to-waterline guidance. They are a selection starting point, not a substitute for checking the installation manual and the exact product configuration.
| Garmin motor family | Bow-to-waterline measurement | Recommended shaft length | Common decision context |
|---|---|---|---|
| Force Pro | 0–19 in. | 50 in. | Lower bow mounting height |
| Force Pro | 15–26 in. | 57 in. | More depth margin within Force Pro range |
| Force Kraken | 0–19 in. | 48 in. | Lower-freeboard Kraken applications |
| Force Kraken | 15–34 in. | 63 in. | Moderate bow height |
| Force Kraken | 26–46 in. | 75 in. | Higher bow or rougher-water margin |
| Force Kraken | 38–61 in. | 90 in. | Tall freeboard and many coastal applications |
| Force Kraken | 53–81 in. | 110 in. | Very high freeboard and large coastal boats |
Measurement note: Garmin states that Force Kraken shaft length is measured from the bottom of the shaft cap to the top of the prop drive. Always compare products using the manufacturer's stated measurement method.
Garmin Force Pro 50 vs 57: Which One Should You Choose?
The Garmin Force Pro 50 vs 57 decision is most relevant when the measurement falls in the 15- to 19-inch overlap. In that range, both lengths appear within Garmin's published guidance. The best choice depends on how the boat actually operates.
Choose the 50-inch Force Pro when…
- The bow-to-waterline distance fits the lower range.
- You normally fish protected or moderate water.
- A shorter stowed profile better suits the deck layout.
Choose the 57-inch Force Pro when…
- The measurement is above the 50-inch model's published range.
- Regular chop makes extra submersion margin valuable.
- The bow and stowed position can accommodate the longer shaft.
Ready to compare both configurations? View available Garmin Force Pro trolling motors and check the shaft length shown in each product title and specification area.
Choosing a Garmin Kraken Shaft Length
The wider Garmin Kraken shaft length range is useful because bow height varies dramatically among flats boats, pontoons, bay boats, deep-V fishing boats and large center consoles. The following summaries help interpret the chart, but the measured range remains the key input.
Do Not Forget Stowed Clearance
Shaft length solves only the deployed-depth question. Before buying a 75-, 90- or 110-inch trolling motor, confirm the complete installation:
- Mount footprint and structural backing beneath the deck
- Clearance around bow rails, cleats, anchor lockers and windlasses
- Where the motor head and shaft rest when stowed
- Support or stabilizer requirements for the selected model
- Trailer, dock and cover clearance
- Cable routing for power, built-in sonar and optional LiveScope equipment
Frequently Asked Questions
What size Garmin trolling motor shaft do I need?
Measure vertically from the planned bow mounting surface to the waterline, add 8 inches if you regularly operate in sizable waves, and compare the result with Garmin's Force Pro or Force Kraken range.
Should I choose a longer trolling motor shaft for rough water?
Extra length can help keep the propeller submerged as the bow moves, but the shaft must still fit the deck and stowed position. Garmin specifically recommends adding 8 inches to the bow-to-waterline measurement when sizable waves are common.
What bow measurement fits a 90-inch Garmin Kraken?
Garmin's published range for the 90-inch Force Kraken is a 38- to 61-inch bow-to-waterline measurement.
What bow measurement fits a 110-inch Garmin Kraken?
Garmin recommends the 110-inch Force Kraken for a 53- to 81-inch bow-to-waterline measurement, subject to installation clearance and operating conditions.
Can I choose shaft length from boat length?
Boat length alone is not enough. Two boats of similar length can have very different bow heights, deck layouts and wave exposure. Use the actual vertical bow-to-waterline measurement.
Match the Motor to the Boat
Measured Your Bow? Compare the Available Shaft Lengths.
Shop Force Pro and Force Kraken options by shaft size. If your measurement sits near a range boundary, send the boat details before ordering.
Shop Garmin Trolling Motors Get Shaft-Length Help