Trolling motor shaft length is one of the most important decisions you have to make to settle on an ideal motor for your boat.
It can be a headache, especially for determining the bow mount trolling motor shaft length which tends to vary greatly across different boats.
Selecting the wrong trolling motor shaft length will make the trolling motor much less efficient and even affect your boating activities with fish-spooking noise.
So how long should your trolling motor shaft be?
In this post, you will learn three easy ways to determine the right trolling motor shaft length for your specific boat (including the deep v models, pontoon boat, bass boat, kayak, Jon boat, bay boat, etc).
What if you got the wrong trolling motor shaft length?
No worries. Here we will discuss some feasible ways to help you make it right.
Continue reading for steps to measure shaft length for trolling motor, tips to change your existing shaft length, recommendations on the long and short shaft trolling motors, and everything you want to know about trolling motor shaft length.
Table of content:
- Why Correct Trolling Motor Shaft Length Is So Important
- What’s Trolling Motor Shaft (with Diagram)
- How to Measure Trolling Motor Shaft Length: 3 Easy Ways
- Trolling Motor Shaft Length on Different Boats
- How to Change Shaft Length on Trolling Motor
- Short & Long Shaft Trolling Motor Recommendations
- FAQs About Trolling Motor Shaft Length
Importance of Selecting Correct Trolling Motor Shaft Length
Choosing the correct trolling motor shaft length is crucial to make sure it works correctly with optimal thrust.
If the trolling motor shaft is too short, the prop won’t be sufficiently submerged (especially in choppy waters), causing noisy cavitation bubbles that scare away fish.
So can you put a longer shaft on a trolling motor? What happens if your trolling motor shaft is too long?
Yes, you can put a longer shaft on a trolling motor but take note of the inconveniences it brings.
The biggest risk is that it can catch on the bottom. The rocks, weeds, and logs can shorten the life of your motor if the trolling motor shaft is so long that makes contact with those underwater hazards.
Besides that, a longer shaft length than needed will increase drag, making the motor less efficient.
Also, don’t forget the extra effort to stow the motor and extra space to store it.
If you’ve searched around or asked in the community, you will find a lot of experienced anglers suggest a longer trolling motor shaft than short.
Is a longer shaft better on a trolling motor?
The short answer is YES.
Comparing the disadvantages of having a shorter vs longer shaft length, it seems that opting for the longer shaft is a more acceptable solution. If you want to shorten your trolling motor shaft to the most ideal length, click to learn how.
What’s Trolling Motor Shaft
Before we get into the trolling motor shaft measurement steps, you need to know how it’s defined and measured.
So where to measure trolling motor shaft length?
Basically, the trolling motor shaft length is measured from the bottom of the motor head to the top of the propeller housing, just as the picture shows below.
The rule of thumb is you need to have 12” (30 cm) submerged in the water for a proper shaft length.
Note: Some trolling motors come with adjustable shaft length which makes them more flexible in fitting various applications. Click here to check the most popular models with different shaft lengths.
How to Measure Trolling Motor Shaft Length: 3 Easy Way
So how long should my trolling motor shaft be? What size shaft trolling motor do I need?
Here we’ve summarized three easy ways to help you decide the correct shaft length for your trolling motor.
These methods are universal and can apply to measuring the trolling motor shaft length for all types of boats including deep V, kayaks, bass boats, Jon boats, canoes, etc.
#1. Trolling Motor Shaft Length Calculator
The trolling motor shaft length calculator allows you to know the exact length you need for your specific boating conditions, so you can find a motor with the length closest to your requirement.
Follow our simple steps to get your ideal trolling motor shaft length.
First, get the recommended minimum shaft length for the trolling motor with the following two steps:
- Step 1: Measure the distance from the mounting spot on the bow/transom, down to the waterline.
- Step 2: Add 20” (51 cm) to get the minimum desired trolling motor shaft length required.
*The 20” (51 cm) includes the 8” (20 cm) top part of the shaft from the boat deck to the handle, and 12” (30 cm) minimum depth below the water surface.
Next, you need to consider other variations to suit your specific fishing situations:
- Step 3: Add 5″ (13 cm) to waterline measurement if you fish in rough waters or offshore often
- Step 4: Add 12” (30 cm) to the measurement if you prefer to steer a hand controlled motor while standing up
To summarize, here is the trolling motor shaft length measurement for different use cases:
- Freshwater/Calm Water = Bow/Transom to Waterline Measurement + 20” (51 cm)
- Saltwater/Rough Waters = Bow/Transom to Waterline Measurement + 25” (64 cm)
Pro Tip: The calculator might not give you a perfect answer to fit the shaft length options available. If you are indecisive about two trolling motor shaft length options, always go to the longer one since it’s much easier to shorten the shaft with adjustment.
#2. Refer to the Shaft Length Recommendation Chart
To make the trolling motor shaft selection easier, a lot of manufacturers have published some official charts and guides that you can refer to easily. For example, here is the shaft length recommendation from Minn Kota:
Minn Kota Bow Mount Trolling Motor Shaft Length
| Bow to Waterline Measurement | Recommended Shaft Length |
| 0” – 10” (0–25 cm) | 36” (91 cm) |
| 16” – 22” (41–56 cm) | 42” – 45 ” (110–110 cm) |
| 22” – 28” (56–71 cm) | 48” – 52” (120–130 cm) |
| 28” – 44” (71–112 cm) | 54” – 72” (140–180 cm) |
| 45” + (110 cm +) | 87” – 100” (220 cm) |
Minn Kota Transom Mount Trolling Motor Shaft Length
| Transom to Waterline Measurement | Recommended Shaft Length |
| 0” – 10” (0–25 cm) | 30 in (76 cm) |
| 10” – 16” (25–41 cm) | 36 in (91 cm) |
| 16” – 22” (41–56 cm) | 42 in (110 cm) |
This chart is only for a rough reference, and the recommendation can vary across different brands due to the shaft lengths available within their product lines. For example, the Newport Vessels and Garmin trolling motor shaft lengths are suggested a bit differently as follows:
Garmin Trolling Motor Shaft Length
| Bow to Waterline Measurement | Recommended Shaft Length |
| 0″ – 19″ | 50″ |
| 15″ – 26″ | 57″ |
Newport Vessels Trolling Motor Shaft Length
| Transom to Waterline Measurement | Recommended Shaft Length |
| 0” – 9” | 24” – 30” |
| 10” – 15” | 30” – 36” |
| 15” – 22” | 36” – 40” |
| 21” – 25” | 40” + |
#3. Ask Manufacturer
The most straightforward way to know the trolling motor shaft length for your boat is to ask the manufacturer or a nearby authorized dealer directly.
It’s especially effective if you have settled on a certain brand.
They will have formulas to help you find the best trolling motor length with the most practical tips based on their experience dealing with customers’ queries.
Here are some quick links to get you connected with the specialist from some popular trolling motor brands:
- Minn Kota Support (Find a Dealer)
- MotorGuide Support (Find a Dealer)
- Garmin Support (Find a Dealer)
- Lowrance Support (Find a Dealer)
Trolling Motor Shaft Length on Different Boats
So what size trolling motor do I need for my 16 (20 or other lengths) foot boat? What length trolling motor do I need for bass tracker 175? What’s the trolling motor shaft length for a kayak (canoe, bass boat, Jon boat)?
Different boats and sizes will require different trolling motor shaft lengths.
Here we’ve summarized the most popular shaft lengths selected and ordered by the respective boat users.
You may refer to the chart below for a general idea of the shaft length you need for different boat models:
| Boat | Popular Shaft Length |
| Pontoon Boat | 60” (150 cm) |
| Jon Boat | 42” (107 cm) |
| Kayak | 24” (61 cm) |
| Canoe | 30” (76 cm) |
| Bass Boat | 45” (114 cm) |
Note: This chart is just for your reference. It’s highly suggested to take the measurement and calculate the accurate shaft length for your trolling motor (as discussed above).
Adjusting Shaft Length on Trolling Motor
There is often the case that someone selected the wrong trolling motor shaft length and desperately asked help to make it right.
So can you change the shaft length on a trolling motor?
Luckily the answer is yes.
If you are one of those who found the trolling motor shaft too long/short, here is what you can do to save your expenses.
#1. Shorten Your Trolling Motor Shaft
It’s relatively easy to shorten the trolling motor shaft length if it’s too long. Just be careful not to damage the cords inside.
Here are the basic steps and tools needed to shorten your trolling motor shaft:
Step 1: Take off the non-essential components on the trolling motor such as the head unit and any other attachments.
Step 2: Disconnect the cords from the motor head (Take a picture in case you forget the wiring)
Step 3: Mark the spot where you want to cut the trolling motor shaft.
Step 4: Use the cutting tool to cut the trolling motor shaft to your desired length.
Step 5: Carefully feed the wires back through, and reattach the motor head and propellers.
There are a lot of video tutorials on this topic with step-by-step guides. For example, the video from Kayak DIY (using the cutting tool) and OneObjective (without the cutting tool).
If you find it challenging, you can consult the manufacturer and have the shaft shortened at an authorized service center or find a technician to do it for you.
Editor’s Note: If you find the trolling motor shaft too long, you can always adjust the shaft depth upward with the depth collar adjustment. This solution is suitable for nearly all trolling motors and the depth collar kit is available from the manufacturer (brand specific) as accessories.
#2. Lengthen Your Trolling Motor Shaft
Lengthening the trolling motor shaft length is much more challenging and technically demanding although it’s possible.
The thing is that you need to extend the wires that run up the inside of the shaft.
The video tutorials below will give you some helpful insights on how to extend the trolling motor shaft and the wires inside.
Alternatively, you might consider the trolling motor shaft replacement and buying a new shaft.
However, bear in mind that changing the trolling motor shaft length will void your warranty and the trolling motor is likely to be not as durable as it was. So be careful before you make the move.
Tip: If you want to avoid the possible risks with the change, you can sell the trolling motor first and get a trolling motor with the correct shaft length.
Short & Long Shaft Trolling Motor Recommendations
Have decided on the best trolling motor shaft length for your boat?
Currently, trolling motors are available with a length from 24” the shortest to 108” the longest.
Here are some recommendations on the best short and long shaft trolling motors:
Bow Mount Trolling Motors
| Product Model | Application | Available Thrust (lb) | Shaft Length (inch) | Price |
| Minn Kota Terrova | Freshwater | 55, 80, 112 | 45, 50, 60, 72 | Check Price |
| Minn Kota Riptide Terrova | Saltwater | 55, 80, 112 | 54, 60, 72, 87 | Check Price |
| MotorGuide Xi3 | Freshwater | 45, 55, 70 | 36, 48, 54, 60 | Check Price |
| MotorGuide Xi3 Saltwater | Saltwater | 55, 70 | 36, 48, 54, 60 | Check Price |
| Garmin Force | Freshwater | 80, 100 | 50, 57 | Check Price |
| Lowrance Ghost | Freshwater | 97, 120 | 47, 52, 60 | Check Price |
Transom Mount Trolling Motors
| Product Model | Application | Available Thrust (lb) | Shaft Length | Price |
| Minn Kota Endura | Freshwater | 30, 40, 45, 50, 55 | 30, 36, 42 | Check Price |
| Minn Kota Riptide Transom | Saltwater | 45, 55, 80, 112 | 36, 42, 52 | Check Price |
| Newport Vessels Kayak Series | Freshwater & Saltwater | 36, 55 | 24 | Check Price |
| Newport Vessels NV Series | Freshwater & Saltwater | 36, 46, 55, 62, 86 | 30 | Check Price |
| MotorGuide R5 | Freshwater | 70, 80, 105 | 42 | Check Price |
| MotorGuide R5 Saltwater | Saltwater | 80, 105 | 42, 50 | Check Price |
| MotorGuide R3 | Freshwater | 30, 40, 45, 55 | 30, 36, 42 | Check Price |
| MotorGuide R3 Saltwater | Saltwater | 45, 55 | 18, 36 | Check Price |
Note: The long and short shaft saltwater labeled trolling motors can also be used in freshwater. The thrust and length availability will be affected due to the
If you are looking for other trolling motor shaft options and brand recommendations, feel free to leave us a comment below and I will get back to you asap.
FAQs About Trolling Motor Shaft Length
Find the hottest questions and quick answers to your confusion about trolling motor shaft length.
#1. What’s the longest trolling motor shaft length?
By far, the longest trolling motor shaft length is 108” from Rhodan Marine. Click here to learn more information about this trolling motor.
#2. Can a trolling motor shaft be too long?
If your trolling motor shaft is too long, it can cause a lot of inconveniences although it can work with no problems.
As discussed, it can easily touch the bottom. The rocks, weeds, and logs can be a potential issue if you are fishing in shallow waters. Besides that, it will cause more drags, and makes extra trouble for the motor stow and storage.
#3. Can a trolling motor shaft be too short?
If the trolling motor shaft is too short, it will cause cavitation and noise which damage the motor itself and scare away fish.
#4. Is a longer shaft better on a trolling motor?
As a suggestion from experience, a longer shaft is better than shorter. If you are uncertain about which trolling motor shaft length to choose, always go for the longer one.
#5. Can you adjust the shaft length on a trolling motor?
For the trolling motors come with adjustable shaft length, you only need to follow the instructions in the manual to easily and safely adjust the shaft length on the trolling motor.
However, if the trolling motor shaft length is not adjustable as default, you can still shorten or lengthen the shaft with some extra effort. Click to learn how.