Can I Take My Freshwater Boat in Saltwater?

Beside how much further you can get from safe harbor, there is one big difference between saltwater and fresh: the salt. Saltwater is about 10 times as corrosive as fresh water.

The Great Lakes or any western reservoir can get plenty sporty when there is wind with fetch over deep water. Out west there are few glassy days sunrise to sunset. At Elevenmile in Colorado’s South Park, on many days the smart boaters head for the ramp at the first sign of a rising breeze; beat the rush — last guy off the water’s going down. Lake Superior famously swallowed a 700-foot freighter whole.

The lakes of the Canadian Shield, often uncharted and rife with rocky reefs jutting from the depths to within inches of the surface, can give you all the navigational fun you would want. Thinking you’re running over 50 feet of water and then seeing you’re suddenly in two will jolt you fully charged and white-knuckled, reducing the universe down to the display on your depth finder.

You can find a world of hurt on any body of water if you’re incautious and exceed your boat’s or its captain’s (i.e., your) limits, but neither Lake Powell (what’s left of it) nor central Tennessee’s Percy Priest Lake and its miles of submerged stumps are going to eat the cleats off your bass boat in one summer.

All boats are compromises, as they say, and we want our boats to cover as much ground, so to speak, for us as possible. Boaters along the coasts have freshwater and saltwater opportunities. Great Lakes boaters will likely have enough boats to be thinking about a haul down I-75 to warmer latitudes. And, finally, there are anglers far inland who dream of pulling their rigs to the nearest salty edge of the continent and really gettin’ down with some big game.

Your motor is the first and most obvious component of your boat to consider, since saltwater will be flowing through it. All modern outboards are salt-capable and are not going to die from a day in the salt, employing as they do corrosion-resistant materials in places coming into contact with water, but you should flush the motor thoroughly with freshwater after use in the salt. Sterndrives, too, are usually fine in the salt, with a couple of caveats. The first is that most inboard/outboards don’t lift entirely out of the water, so leaving your boat moored means steady to continuous contact with the salt. Additionally, I/O’s with raw water cooling are getting greater exposure to saltwater internally than I/O’s that use a closed freshwater cooling system with a heat exchanger to transfer heat away.

Trolling motors are a different story. Minn Kota, MotorGuide and other manufacturers produce lines of trolling motors engineered specifically for saltwater use. If your boat is intended for both environments, get the saltwater version of the trolling motor you want. Using your non-saltwater troller in salt can even void its warranty.

Trolling motors are electrical components, and electricity is conducted over metal wire, meaning the electrical circuits on your boat are a vulnerability. Often, boats engineered for freshwater use have less corrosion-resistant electrical systems than saltwater boats, which are typically wired with marine-specific tinned wiring and heat-shrink connectors. Plain crimped connectors and automotive-grade wiring simply cannot stand up to frequent saltwater use. For occasional use, dielectric grease and other corrosion-inhibiting coating substances are critical for maintaining electrical systems. If your depth finder is suddenly throwing numbers all over the place, clean and grease the connectors.

An emergency occurring miles offshore — say a hooked sailfish comes unexpectedly aboard, to pull a situation from the news — is a bigger emergency than one a few hundred yards down the shoreline from the ramp on a 400-acre lake. Thus, boats designed to run offshore are built with greater safety margins. Hulls are typically stronger to stand up to the beating delivered by rough seas. Cockpit floors will sit above the waterline and use gravity to self-bail any water that comes over the gunwales. Little semi-V fishing boats rarely have bilge pumps. You don’t need a two-way radio at Lake Guntersville, but should have one aboard when heading out on the Gulf of Mexico or into the Everglades backcountry. 

Even anchoring has a different set of concerns in saltwater. If you’re boating in coastal Maine, with its rocks and 10-foot tides, your anchor rode should be chain on the bottom end to withstand abrasion, and you should have a knife aboard and handy for cutting yourself away quickly if you ever need to. You don’t want to get swept out to sea if you’re disabled, and you won’t want to just sit there if your anchor is wedged and there’s a freighter bearing down on you. That trusty mushroom anchor with the worn-out ski rope knotted through the eye simply isn’t going to cut it in the salt.

Pure water — distilled or deionized — does not conduct electricity, but neither the seas nor the lakes are pure, and saltwater, loaded with chlorine ions, conducts electricity better than freshwater. Electrolysis is a corrosive chemical reaction induced by electrical currents passing through water between two different metals. Boat motors are fitted with sacrificial anodes that prevent corrosion by electrolysis: the replaceable anode corrodes instead of your lower unit.

You’re going to launch, do your thing and then, after a great day on the water, clean your boat and trailer. In a car wash or in your driveway, wash everything well, then hook up a garden hose to the flushing port and flush the motor (while not running) according to the manufacturer’s recommendation in the owner’s manual. For outboards without flushing ports, use muffs with the engine idling. Do not leave the boat unattended if flushing with muffs and the motor at idle. That’s a good way to trash your motor if the muffs slip. Also thoroughly rinse the outside of your engine, the prop, steering components, motor bracket and tilt and trim mechanism.

• Don’t forget your bilge pump. Re-install the drain plug and put enough water in the bilge to flush the pump well.
• Salt deposits won’t just wash away. A cleaner such as Starbrite Salt-off will dissolve salt deposits and even then elbow grease may be required.

A trailered boat vacations on the water and lives on a trailer, and for boats salt is a homewrecker. A galvanized steel or, even better, aluminum trailer is really what you want for any saltwater use. The painted steel trailers used to transport so many freshwater boats will get salt in places you’ll never be able to get it out of, and once it’s there the damage is underway. In fact, even a single dunking in saltwater can spell the end for a painted steel trailer with a box-channel (as opposed to C-channel) frame. It might take a few years, but eventually corrosion from the salt trapped in the frame will eat it alive from the inside out.

Whatever your trailer’s frame is made of, you’ll want to thoroughly wash it down after saltwater use. Pay particular attention to the leaf springs (if it has them), brakes, bunk brackets, fenders and the undersides of the frame.

Saltwater intrusion in trailer hubs is also very bad. An annual overhaul of the hubs of any boat trailer is a good habit, and only more so if the trailer sees the salt. If you have a long haul home from the coast, check your hubs before hitting the road.

You want to keep your head on straight no matter where you’re boating, but the ocean really is a different animal. An onshore wind is not going to stack up an outgoing tide in an inlet on Lake Texoma. You’re not going to get swept into the North Atlantic from Lake Okoboji. Lake of the Woods is generally free of tropical storms and sharks. (On the other hand, if you run 30 knots into a leaping 30-pound fish, the physics are the same whether it’s a stingray or a silver carp.)

Ask yourself: What do I need to do to prepare myself and my boat for safe and environmentally responsible boating where I’m headed? An example: If you are going to operate a motorized vessel in the waters of Everglades National Park, you must take an online course, pass a test, and carry your certificate onboard. Turtle and eel grass flats, coral, and manatees are examples of marine life and habitat that you are responsible for treating well. 

Have tide charts aboard for the area you are in. If you’ve never piloted a boat in moving water, loading your boat in a ripping tidal current is going to be a new and challenging experience.

And keep in mind that the smart thing may be to look at the weather forecast and say, “No, not today.”

Let’s say you’re interested in a boat for inland use. Is there any reason to consider a boat targeted for saltwater use?

Microskiffs, the little brothers of flats skiffs, are catching the attention of fly anglers in the interior for a couple of reasons. The first is that there are few fly rod and fly fishing friendly options in production among freshwater fishing boats. Muskellunge fishermen are using eight- and nine-foot casting rods for tossing massive muskie lures, and boats with rod lockers long enough to accommodate those long sticks are showing up. But you have to go up to a 21-footer or so to get to that kind of rod storage, and then you are still casting from a space with endless places to hang up a fly line. Any microskiff is going to carry at least four fly rods strung and ready to fish, no problem.

The other factor is the rise of carpin’, fly fishing for the ubiquitous common carp. Trout anglers graduate to carp — a.k.a. Rocky Mountain bonefish — and the next thing they know they’re looking at boats. The template is already there: a poling platform, a casting deck, a fish with its butt up and its face in the mud. Squint and it almost looks like you are creeping up on a tailing red in the Louisiana marsh.