Life is precious. This is never more apparent than after the loss of a loved one, which sadly is a part of life sometimes. We lost my father-in-law, Dan, recently and the experience has inspired me to post a project that he would surely enjoy. Like Dan, I have a fishing boat. Time on the water to boat, swim and fish with my family and friends is time I consider precious. When I captain the boat, though, I want to rid myself of the stress that comes with an anchor that won’t catch or a boat that settles out-of-position. This season, I will rid myself of this stress by upgrading my boat with a trolling motor that has an autopilot.
You had me at “Autopilot”
A couple of years back I fished on someone else’s boat with the Minn Kota i-Pilot. That person landed an absolutely magnificent Northern Pike, but it was me that got hooked! The way our boat transitioned from trolling to anchoring let us focus on getting lures in the water, and the tech paid off in spades. Truthfully it must be experienced to be appreciated. That said, I’ll share Minn Kota’s explanation here so that you can at least get a rough idea of the greatness that awaits my family craft, the Boat Cheeks.
The Wiring Plan
The trolling motor I picked is a 24V model, and my boat was previously wired for a 12V trolling motor. This will make the replacement a bit more complex, but the project is still quite manageable with a few key tools on-hand.
Objectives
- Replace the old marine battery with 2 new marine batteries
- Replace the old, corroded wires with new marine 8 gauge primary wire
- Replace the old, underrated trolling motor plug with a new high-current plug
- Replace the old Circuit Breaker (CB) with a new one rated to the motor’s specification
- Add a new, 2-bank onboard charger to the forward battery compartment
- Add the optional 12V Bluetooth (BT) heading sensor to augment the i-Pilot reference system
- Mount the new trolling motor and connect
Interconnects
Parts
Quality, marine-grade parts are the only safe parts to use on a boat. Marine electrical parts, specifically, are made to resist corrosion in the wet environment of boats.
| Part | Link | QTY | Notes |
|---|---|---|---|
| Trolling Motor | Amazon | 1 | |
| Heading Sensor | Amazon | 1 | Some motors include this; mine did not. |
| 70A Trolling Motor Plug | Amazon | 1 | |
| 70A Trolling Motor Receptacle | Amazon | 1 | |
| 24V Marine CB | Amazon | 2 | Keep a spare in the tackle box! |
| Primary Marine Shrink Tubing | Amazon | 1 | Sold in 4′ lengths, use 1/2″ for 8 gauge |
| Standard Marine Shrink Tubing | Amazon | 1 | Sold as a pack of sizes that work for smaller guages |
| Non Insulated Butt Connectors | Amazon | 1 | Sold as pack. Must use shrink tubing to insulate. |
| Tinned Lugs – 8 AWG 5/16″ ring | Amazon | 2 | Sold as 2-pack – need 3 for this project |
| Tinned Lugs – 8 AWG 1/4″ ring | Amazon | 1 | Sold as 2-pack – need 1 for this project |
| Primary Marine Wire – red | Amazon | as-needed | Consult trolling motor manual for wire size. For me, 8 AWG. |
| Primary Marine Wire – black | Amazon | as-needed | Consult trolling motor manual for wire size. For me, 8 AWG. |
| Heat Shrink Insulated Connectors | Amazon | 1 | Nice multipack with lots of options |
Specialty Tools
Marine cable terminations are crimped and not soldered. I’m lead to believe the ABYC standards spell out why if you are so inclined to search for that. For the appropriate strength and corrosion resistance, a proper crimper and heat gun are required tools to do the job right. Moreover, you’ll want a torque wrench for some key mechanical fastenings. Lastly, a good multimeter will help with safety along the way to verify voltages are as-expected before using the new motor.
| Tool | Link | Notes |
|---|---|---|
| Crimping Tool (Set) | Amazon | Love this crimper: one-handed and can tackle battery lugs as large as 4 gauge. |
| Electric Heat Gun | Amazon | Fantastic – fast and easy heat shrink! |
| Torque Wrench | Amazon | Loose battery terminals can be dangerous – tighten to specification! |
| Multimeter | Amazon | Don’t connect the trolling motor without confirming the DC voltage. |
A Word of Caution
A boat’s electrical system is dangerous. It can electrocute you, start a fire, or strand you far from home.
A Word of Advice
A trolling motor installation can easily and affordably be scheduled with a local professional. If you are inexperienced or uncomfortable with DC electrical upgrades and repairs, please search your area for powersports mechanics and/or boat dealers with shops. Then hire this job out.
Read the Factory’s Manual
The trolling motor installation guide is the obvious and best choice for instructions to install the trolling motor. Most manufacturers, including the stellar Minn Kota brand, post installation guides online. I recommend researching these prior to your purchase.
Here are the manuals for the parts I’m using:
| Trolling Motor | manual (install).pdf ; manual (owner).pdf ; mounting-dimensions.pdf |
| Heading Sensor | manual.pdf |
| i-Pilot | manual (quick-reference).pdf ; manual (full).pdf ; troubleshooting.pdf |
| 70A Trolling Motor Plug | specifications.pdf |
| 70A Trolling Motor Receptacle | specifications.pdf |
| Crimping Tool (Set) | oem product page |
| Electric Heat Gun | manual.pdf |
| Torque Wrench | manual.pdf |
| Multimeter | manual.pdf |
Terminate Wire Properly
The Right Tool – The Right Part
Marine heat shrink will have adhesive lining that activates when the tube is shrunk with a heat gun. It will likely ooze out a bit, which is a great sign the crimp/wire is sealed!
Marine wire and crimp parts should be tinned copper to resist oxidation and its ill-effect of increased wire resistance. Use a proper wire crimper with terminal-specific dies.
The Right Technique
Read both of these posts from Marine How To. We’re not affiliated, but there’s great teaching on these pages:
- https://marinehowto.com/marine-wire-termination/
- https://marinehowto.com/battery-melt-down-narrowly-averted/
Results
The automation of an autopilot, be it in an airplane or part of a boat trolling system, reduces workload. Pilots benefit with increased situational awareness — managing weather, traffic and the occasional drunk idiot. Boat captains can get easier heading control and instant-anchoring when it’s time to deal with “fish on” or the occasional drunk idiot :). I’m personally quite excited to run my new automation to its fullest, so that I can make the most of precious time on the water.
Insightful reading!