How to Choose the Right Shaft Length for Your Garmin Force Kraken
Share
The Most Important Decision You'll Make When Choosing a Trolling Motor
The Garmin Force® Kraken is available in five shaft lengths — 48", 63", 75", 90", and 110". Every shaft length delivers the same brushless motor platform, the same multi-band GPS Anchor Lock, the same reverse thrust, and the same Garmin ecosystem integration. The only difference is how deep the propeller sits in the water.
That difference matters enormously. A shaft that's too short will cavitate in chop, lose prop depth at speed, and compromise Anchor Lock performance. A shaft that's too long is harder to install, consumes more bow space, and can actually reduce steering response. Getting the shaft length right is the single most important specification decision you'll make.
How to Choose Your Shaft Length — Step by Step
Follow these five steps to select the correct Force Kraken shaft for your boat:
- Measure from the bow mounting surface to the waterline. This is your bow-to-waterline distance — the vertical measurement from the water's surface up to the top of your bow where the motor mount plate sits.
- Load your boat before measuring. Measure with a full fishing load — fuel, gear, coolers, and any passengers you typically fish with. A loaded boat sits lower in the water, which changes your measurement.
- Add 8" if you regularly fish in rough water. If you fish offshore, on the Great Lakes, or in conditions with significant wave action, add approximately 8 inches to your measurement. This accounts for the bow rising in heavy chop and the prop losing depth.
- Match your measurement to Garmin's recommended shaft range. Use the table below to find your shaft.
- If you're between two sizes, choose the longer shaft. A shaft that's slightly longer than needed is far less problematic than one that's too short.
Garmin Force Kraken — Official Shaft Selection Table
| Bow-to-Waterline Distance | Recommended Shaft | Best For |
|---|---|---|
| 0–19" | 48" | Bass boats, flats boats, and lower-profile bay boats |
| 15–34" | 63" | The all-around choice for most bay boats and center consoles |
| 26–46" | 75" | Offshore-capable center consoles and rough-water coastal fishing |
| 38–61" | 90" | Large offshore boats where maintaining prop depth in heavy chop is essential |
| 53–81" | 110" | Premium offshore, guide, and commercial vessels requiring maximum shaft length |
Source: Garmin's published shaft-selection methodology for the Force Kraken lineup.
Two important rules from Garmin:
- If you frequently fish in larger waves, add approximately 8 inches to your bow-to-waterline measurement before selecting a shaft.
- If your measurement falls into an overlap between two shaft lengths, choose the longer shaft.
Note: Ranges overlap intentionally. When your measurement falls in an overlap zone, choose the longer shaft if you fish in rough water or offshore conditions, and the shorter shaft if you fish primarily in calm, protected water.
Real-World Examples — Applying the Guide to Your Boat
Example 1: 22-Foot Bay Boat with a Low Bow
A 22-foot bay boat with a relatively low bow typically has a bow-to-waterline measurement in the 18–28" range. For calm inshore and nearshore fishing, the 63" shaft is almost always the right choice. If this boat regularly fishes in moderate chop or coastal conditions, the 75" becomes worth considering.
Example 2: 24-Foot Center Console, Inshore/Nearshore
A mid-size center console with a bow-to-waterline measurement of 25–35" is well served by the 63" or 75" shaft depending on conditions. Anglers who fish primarily in protected water choose the 63"; those who regularly fish in open coastal water or moderate offshore conditions choose the 75".
Example 3: 28-Foot Offshore Center Console with a High Bow
A 28-foot offshore center console with a high freeboard typically has a bow-to-waterline measurement of 40–55". For this boat, the 90" shaft is the standard choice. If the measurement exceeds 53" or the boat regularly fishes in heavy offshore swells, the 110" becomes the right call.
Example 4: 20-Foot Bass Boat
A typical 20-foot bass boat has a bow-to-waterline measurement of 12–18". The 48" shaft is the correct choice — and the only Force Kraken model that includes the GT56UHD-TR transducer (Traditional CHIRP + ClearVü + SideVü) built directly into the motor.
Example 5: Large Offshore Center Console or Guide Boat, 32+ Feet
Very large offshore center consoles, triple-engine tournament boats, and professional guide boats with bow-to-waterline measurements above 53" require the 110" shaft — Garmin's maximum shaft length, designed specifically for this category of vessel.
Common Mistakes When Choosing a Shaft Length
Mistake #1 — Choosing by Boat Length Instead of Bow Height
Boat length is not a reliable indicator of shaft length. A 24-foot bay boat and a 24-foot center console can have dramatically different bow-to-waterline measurements. Always measure — never estimate based on overall boat length.
Mistake #2 — Measuring Without a Full Load
Measuring an empty boat gives you an inaccurate bow-to-waterline distance. A fully loaded boat sits lower in the water, which increases your effective bow height. Always measure with a realistic fishing load.
Mistake #3 — Not Accounting for Rough Water
Anglers who fish offshore, on the Great Lakes, or in coastal conditions with regular wave action frequently underestimate their shaft length requirement. In heavy chop, the bow rises and falls — a shaft that's adequate in calm water can cavitate repeatedly in rough conditions. Add 8" to your measurement if rough water is part of your regular fishing.
Mistake #4 — Choosing the Shorter Shaft When Between Sizes
When a measurement falls in an overlap zone, some anglers choose the shorter shaft to save money or because it seems like the safer choice. It isn't. A shaft that's too short in your conditions will cavitate, lose Anchor Lock performance, and reduce steering control. When in doubt, go longer.
Mistake #5 — Choosing the Longest Available Shaft "Just to Be Safe"
A shaft that's longer than your boat requires doesn't improve performance — it can actually reduce steering response, make the motor harder to stow, and increase stress on the mount. Match the shaft to your actual bow-to-waterline measurement.
When in Doubt — Choose the Longer Shaft
If your boat falls between two recommended shaft lengths, the longer shaft is almost always the better choice. A shaft that is too short can allow the propeller to come out of the water in waves, reducing steering control and Anchor Lock performance. A longer shaft can typically be managed in normal conditions without meaningful performance loss. This is consistent with Garmin's published guidance for the Force Kraken lineup.
Each Shaft Length — Who It's For
48" — Bass Boats, Flats Boats, and Low-Profile Bay Boats (0–19")
The 48" shaft is designed for low-profile freshwater and inshore platforms where the bow sits close to the water. The 48" Black and 48" White are the only Force Kraken models that include the GT56UHD-TR transducer built in — Traditional CHIRP, ClearVü, and SideVü sonar integrated directly into the motor.
→ Shop Force Kraken 48" models
63" — The All-Around Choice for Most Bay Boats and Center Consoles (15–34")
The most versatile shaft in the Force Kraken lineup. If you're not sure which shaft you need and your boat is a mid-size bay boat or center console, the 63" is almost certainly the right choice.
→ Shop Force Kraken 63" models
75" — Offshore-Capable Center Consoles and Rough-Water Coastal Fishing (26–46")
The right shaft for larger center consoles that fish in coastal and nearshore offshore conditions where wave action is a regular factor.
→ Shop Force Kraken 75" models
90" — Large Offshore Boats in Heavy Chop (38–61")
For large offshore center consoles and serious offshore fishing platforms where maintaining prop depth in heavy seas is critical. Includes a shaft stabilizer to support the longer shaft during trailering and operation.
→ Shop Force Kraken 90" models
110" — The Flagship for Very Large Offshore, Guide, and Commercial Vessels (53–81")
Garmin's maximum shaft length, designed for very large offshore center consoles, guide boats, and commercial fishing vessels where even a 90" shaft cannot maintain consistent propeller depth. Includes a shaft stabilizer and uses Garmin's pivot-style mount to make the 110" practical to install and stow on large offshore boats.
→ Shop Force Kraken 110" models
Black or White — Does Finish Affect Shaft Selection?
No. Every shaft length is available in both black and white, and performance is identical between the two finishes. Choose based on your boat's color and hardware. White coordinates with white-hulled center consoles and white outboards (Yamaha, Mercury, Suzuki); black coordinates with dark-hulled boats and black outboard trim.
Sonar — 48" vs. 63"–110"
The 48" models include the GT56UHD-TR transducer (Traditional CHIRP + ClearVü + SideVü) built directly into the motor. The 63", 75", 90", and 110" models are transducer-ready — they accept a compatible Garmin GT-series transducer but do not include one. If sonar integration is important to your setup, factor this into your selection.
Frequently Asked Questions
What happens if my trolling motor shaft is too short?
A shaft that's too short will allow the propeller to cavitate — break the surface — in chop or at speed. This reduces thrust, degrades Anchor Lock performance (the GPS can command thrust but the prop can't execute it if it's out of the water), and reduces steering control in rough conditions. In severe cases, the motor can lose contact with the water entirely in heavy swells.
Can a shaft be too long?
Yes. A shaft that's longer than your boat requires reduces steering response due to increased flex at depth, makes the motor harder to stow, increases stress on the mount assembly, and provides no performance benefit. Extra shaft length below the propeller does nothing useful. Match the shaft to your actual bow-to-waterline measurement.
How do I measure my boat correctly?
Launch your boat and load it with a realistic fishing load — fuel, gear, coolers, and any passengers you typically fish with. With the boat in the water at normal load, measure vertically from the waterline up to the top of the bow where the motor mount plate sits. Record this measurement in inches. If you regularly fish in rough water, add 8" before selecting your shaft.
Should I choose the longer shaft if I'm between sizes?
Yes — this is Garmin's published recommendation and the right call in almost every case. A shaft that's slightly longer than needed is far less problematic than one that's too short in your conditions.
Does offshore fishing require a longer shaft?
Usually yes. Offshore conditions — open ocean swells, heavy chop, significant wave action — cause the bow to rise and fall, which reduces effective prop depth. Garmin recommends adding approximately 8" to your bow-to-waterline measurement if you regularly fish in larger waves. This often moves anglers from the 75" to the 90", or from the 90" to the 110".
Which Garmin Force Kraken shaft length is best for a bay boat?
Most bay boats fall in the 63" range, with larger or higher-freeboard bay boats moving to the 75". Measure your bow-to-waterline distance and use the table above to confirm. A 22-foot bay boat with a low bow is typically a 63"; a larger bay boat with more freeboard may be a 75".
Which shaft length is best for a center console?
Center consoles vary widely by size and freeboard. Smaller center consoles (18–24 ft) typically fall in the 63"–75" range. Larger offshore center consoles (26–36 ft) typically fall in the 90" range. Very large offshore center consoles (28–40+ ft) with high bows may require the 110". Always measure — don't estimate based on boat length alone.
What shaft length is best for rough water?
Add 8" to your bow-to-waterline measurement if you regularly fish in rough water, then use the shaft selection table. Rough-water anglers frequently find they need one shaft length longer than their calm-water measurement suggests. When in doubt, choose the longer shaft.
Does shaft length affect Anchor Lock performance?
Yes, indirectly. Anchor Lock uses GPS to hold position, but the motor needs adequate prop depth to execute the thrust commands the GPS system generates. A shaft that's too short in rough conditions will cavitate, reducing the motor's ability to hold position even when the GPS signal is perfect.
Is the Force Kraken available in other shaft lengths?
No. The Force Kraken is currently available in 48", 63", 75", 90", and 110" — these five lengths cover the full range of boats the motor is designed for.
Explore the Complete Garmin Force Kraken Ecosystem
Authorized Garmin Dealer. Expert support before and after your purchase. Free nationwide shipping.