How to Choose the Right Shaft Length for Your Garmin Force Kraken

How to Choose the Right Shaft Length for Your Garmin Force Kraken

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 primary sizing difference is how much shaft reach you have available to keep the propeller properly submerged. Individual Kraken configurations can also differ in included sonar hardware and other model-specific equipment.

That difference matters enormously. A shaft that's too short can allow the propeller to approach or break the surface as the bow rises in waves, reducing thrust and compromising the motor's ability to execute Anchor Lock corrections. A shaft that's too long is harder to install, consumes more bow space, and can create unnecessary complications without providing a meaningful advantage. 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:

  1. 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.
  2. Load your boat before measuring. Measure with a full fishing load — fuel, gear, coolers, and any passengers you typically fish with. Fuel, gear, passengers, batteries, and other equipment can change the boat's running attitude and the vertical distance between the trolling-motor mounting surface and the waterline.
  3. 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 propeller approaching the surface.
  4. Match your measurement to Garmin's recommended shaft range. Use the table below to find your shaft.
  5. If you're between two sizes, consider the longer shaft. When your measurement falls in an overlap zone, the longer shaft is generally the better choice for rough or exposed water conditions.

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, consider the longer shaft.

Note: Ranges overlap intentionally. When your measurement falls in an overlap zone, the longer shaft is generally preferred for rough or exposed water; the shorter recommended shaft may be appropriate for primarily calm, protected water.

Not Sure Which Kraken Shaft Length Fits Your Boat?

Contact TrollingMotors.shop before ordering. Send us your boat make, model, and year, your trolling-motor mounting-surface-to-waterline measurement, and — if possible — a photo of your bow mounting area.

We'll help you evaluate which Garmin Force Kraken shaft length is appropriate for your boat and typical operating conditions.

Real-World Examples — Applying the Guide to Your Boat

Example 1: Bay Boat with a Bow-to-Waterline Measurement of 18–28"

A bow-to-waterline measurement in the 18–28" range falls within the 63" shaft's recommended range. For calm inshore and nearshore fishing, the 63" shaft is typically the right choice. If this boat regularly fishes in moderate chop or coastal conditions, and the adjusted measurement (with the 8" rough-water addition) approaches the 75" range, the 75" becomes worth considering.

Example 2: Center Console with a Bow-to-Waterline Measurement of 25–35"

A measurement of 25–35" falls within the overlap between the 63" and 75" shaft ranges. Anglers who fish primarily in protected water may be well served by the 63"; those who regularly fish in open coastal water or moderate offshore conditions should consider the 75".

Example 3: Offshore Center Console Measuring 40–55"

If the vertical distance from the Kraken mounting surface to the waterline measures 40–55", the boat falls within Garmin's 90" shaft range. If the adjusted measurement reaches the 110" range — particularly after accounting for regular rough-water operation — the 110" should be considered.

Example 4: Bass Boat with a Bow-to-Waterline Measurement of 12–18"

A measurement of 12–18" falls within the 48" shaft's recommended range. The 48" shaft is the correct choice — and the only Force Kraken configuration that includes the GT56UHD-TR transducer (Traditional CHIRP + ClearVü + SideVü) built directly into the motor on select SKUs. Verify transducer inclusion for the specific model before purchasing.

Example 5: Large Offshore or Guide Boat with a Bow-to-Waterline Measurement Above 53"

A measurement above 53" falls within the 110" shaft's recommended range. The 110" shaft is Garmin's maximum shaft length, designed for large offshore center consoles, guide boats, and commercial fishing vessels where even a 90" shaft cannot maintain consistent propeller depth.

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. Measure with the boat loaded as you normally fish it. Fuel, gear, passengers, batteries, and other equipment can change the boat's running attitude and the vertical distance between the trolling-motor mounting surface and the waterline.

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 allow the propeller to break the surface 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. A shaft that's too short in your conditions can allow the propeller to break the surface, reducing Anchor Lock performance and steering control. When your measurement falls in an overlap zone and you fish in rough or exposed water, the longer shaft is generally the better choice.

Mistake #5 — Choosing the Longest Available Shaft "Just to Be Safe"

More shaft length than your application requires can create unnecessary installation, stowage, clearance, and shallow-water complications without providing a meaningful advantage. The goal is adequate propeller submersion for your boat and operating conditions — not simply choosing the longest available shaft.

When You're Between Two Recommended Sizes

If your measurement falls within the overlap between two Garmin-recommended shaft lengths, consider the longer option when you regularly fish rough or exposed water. For primarily calm, protected water, the shorter recommended shaft may be appropriate. 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. Select 48" Black and 48" White configurations include the GT56UHD-TR transducer built in — Traditional CHIRP, ClearVü, and SideVü sonar integrated directly into the motor. Verify transducer inclusion for the specific SKU before purchasing.

→ 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. The 63" shaft covers a broad range of moderate mounting-surface-to-waterline measurements and can suit many bay boats and center consoles. Confirm fit using your actual measurement and normal operating conditions.

→ Shop Force Kraken 63" models

75" — Offshore-Capable Center Consoles and Rough-Water Coastal Fishing (26–46")

The 75" shaft covers Garmin's 26–46" bow-to-waterline range and can be a strong choice for larger center consoles and other boats operating in coastal and nearshore conditions where wave action is a regular factor.

→ Shop Force Kraken 75" models

90" — Large Offshore Boats in Heavy Chop (38–61")

The 90" shaft covers Garmin's 38–61" bow-to-waterline range and is designed for applications requiring substantial shaft reach, including larger offshore center consoles where maintaining propeller depth in rough water 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")

The 110" shaft covers Garmin's 53–81" bow-to-waterline range and provides the greatest shaft reach in the Force Kraken lineup for very high-bow offshore, guide, and commercial applications. 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"

Select 48" configurations 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. Transducer inclusion varies by specific SKU — verify the exact model before purchasing. If sonar integration is important to your setup, factor this into your selection.

Need the Complete System?

For larger offshore installations, our Diamond Complete Systems pair the Force Kraken with a matched 36V lithium power system, charger, wiring, battery mounting, quick-release bracket, and bow mounting solution — bringing together the major trolling-motor, power, charging, electrical, and mounting components in one matched package.

Frequently Asked Questions

What happens if my trolling motor shaft is too short?

A shaft that's too short can allow the propeller to approach or break the surface in chop. This reduces thrust, degrades Anchor Lock performance (the GPS can command thrust but the propeller 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. More shaft length than your application requires can create unnecessary installation, stowage, clearance, and shallow-water complications without providing a meaningful advantage. The goal is adequate propeller submersion for your boat and operating conditions — not simply choosing the longest available shaft.

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?

Generally yes, particularly if you fish in rough or exposed water — this is consistent with Garmin's published guidance for the Force Kraken lineup. If you fish primarily in calm, protected water, the shorter recommended shaft may be appropriate.

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?

Many bay boats can fall within the 63" Kraken's 15–34" bow-to-waterline range, while higher mounting surfaces or rough-water operating conditions may move the application into the 75" range. Measure your actual bow-to-waterline distance and use the shaft-selection table above to confirm.

Which shaft length is best for a center console?

Center consoles vary widely by size and freeboard. Always measure — don't estimate based on boat length alone. Use your bow-to-waterline measurement and the shaft selection table above to identify the correct range, then factor in your typical operating conditions.

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 your measurement falls in an overlap zone and rough water is a regular factor, 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 can allow the propeller to break the surface, 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.

Back to blog