Plenty of freshwater anglers find themselves headed to the salt for a day or two a year. And inevitably, they ask whether a freshwater trolling motor can be used in saltwater.
The simple answer is yes.
But there are reasons you might not want to.
Even the best freshwater trolling motors aren’t designed to withstand saltwater corrosion, and they may even lack the specially sealed electrical connections that prevent saltwater intrusion. Moreover, for most manufacturers, a trip in saltwater voids the warranty on your freshwater motor. That all said, we definitely recommend purchasing a quality saltwater trolling motor.
Do you want to know more about using a freshwater trolling motor in saltwater?
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Fresh vs. Salt: Trolling Motor Differences Explained
When we think about rust and other forms of corrosion, we associate them with plain old water.
But the truth is that fresh- and saltwater are totally different beasts when it comes to corrosion.
Freshwater isn’t terribly corrosive, especially if metal parts have a chance to dry between uses. That’s because freshwater contains very little sodium chloride - salt - typically less than 1%.
By contrast, brackish water contains between 1% and 2.5% sodium chloride, with sea water holding a steady 3.5% salt by volume.
The chloride in salt eats through the surface of exposed metals like steel, corroding them on contact, though experts explain that the exact “rate of corrosion is controlled by the chloride content, oxygen availability, and the temperature.”
More oxygen and more heat increases the rate of corrosion.
Freshwater trolling motors aren’t engineered to prevent corrosion since freshwater doesn’t contain much sodium chloride. Non-stainless steels and other corrodible materials are common in freshwater trolling motors, and beyond some very basic seals and waterproofing, not much else is necessary to ensure durability and longevity.
Non-stainless steels corrode very quickly when exposed to saltwater - even when not submerged.
But that’s not true for saltwater trolling motors. To survive the salt, they need non-corrosive materials like stainless steels, aluminum, polymers, and substantial sealing to prevent saltwater intrusion.
They’re just engineered for a much tougher environment.
And even with this durable construction, industry leaders like Minn Kota recommend limiting saltwater contact as well as thoroughly rinsing your saltwater trolling motor in fresh water after every use to extend its life.
Using a Freshwater Trolling Motor in the Salt
That doesn’t mean that you can’t use a freshwater trolling motor in saltwater, but there are some real-world consequences you need to understand.
First, most manufacturers specifically state that doing so will void your warranty.
If your motor is still covered, I’d probably recommend against taking it into the salt.
Second, you’re going to be exposing your trolling motor to conditions for which it wasn’t designed, and that’s going to cause issues almost immediately - unless you take some careful steps.
Start by coating any exposed metal in a thin layer of grease. That will limit direct contact with saltwater, slowing corrosion substantially. Then, when you’re down for the day, thoroughly rinse your trolling motor with fresh water.
Don’t forget parts like the mounting hardware - they’ll take a beating just by being exposed to salt-laden air.
Aside from warranty issues, if you take the proper precautions, you can use a freshwater trolling motor in saltwater. Do everything you can to protect exposed metal and hidden corossible parts, and rinse the entire motor assembly thoroughly when you’re done.
That’ll help a lot.
But be aware that regular trips to the salt will inevitably shorten the life expectancy of a freshwater motor.
That’s just reality.