12 Signs a Boat Has Been Used in Saltwater (Revealed!)

Saltwater can cause more damage to a boat than fresh water because it’s highly corrosive. So certain precautions are taken before and after using a boat in seawater to protect against saltwater damage. Unfortunately, some boat owners don’t practice these preventive measures only to sell their problem-laden boats to unsuspecting buyers.

Here are 12 signs a boat has been used in saltwater:

  1. Fading paint on the hull
  2. Scratches on the hull
  3. Fiberglass and wood lose their shine
  4. Rust on parts of the outboard motor
  5. Corroded trim tabs
  6. Discoloration around the bolts
  7. Rusty boat trailer or an old boat on a new trailer
  8. Rust on the base plate of the ski pylon
  9. Corroded steering cable support tube
  10. Surface rust in the bilge
  11. Black or dark water intake grate
  12. The carpet has a rough texture

If you boat in saltwater and don’t take the proper maintenance precautions, it can lead to extensive boat damage. In this article, I’ll discuss the effects of saltwater on boats to help you know what to look out for when buying a used boat.

Sailboats in the ocean: how to tell if a boat has been in salt water

1. Fading Paint on the Hull

Metallic parts corrode five times faster from exposure to saltwater than freshwater. Paint serves as a barrier between saltwater and boat hull, preventing corrosion.

So one of the precautions boat owners take when going in salt waters is painting the hull, especially in steel and aluminum vessels. However, saltwater causes paint to chip, fade, and wear fast.

2. Scratches on the Hull

Salt is abrasive. So given a section of the boat hull is submerged and remains in the water for an extended period, the hull suffers the most salt damage. As the boat moves through salt water, the salt rubs against the hull, resulting in scratches.

3. Fiberglass and Wood Lose Their Shine

Fiberglass boats or wooden portions of a vessel tend to lose their shine after prolonged exposure to saltwater. The change in appearance is especially notable below the waterline. Boats used exclusively in freshwater typically retain their shine for longer than those used in saltwater.

small boat moored in saltwater

4. Rust on Parts of the Outboard Motor

You can also tell a boat has been in saltwater by looking at the outboard motor, whose lower limit gets submerged in water. The lower limit consists of multiple moving parts. To protect these parts from the effects of salt water, they’re periodically lubricated.

With time, saltwater depletes the lubricant coating, exposing the outboard motor components to salt damage. Check your outboard motor for rust and corrosive salt buildup.

The YouTube video below by Scott Gregg shows how to flush and desalt your outboard motor to prevent saltwater corrosion.

5. Corroded Trim Tabs

Trim tabs make your boat go faster, stop porpoising, improve fuel efficiency, eliminate squatting, enhance visibility, and reduce hull stress. These independently adjustable steel plates mounted on either side of the boat transom can move up and down when activated.

Trim tabs are metal and hence susceptible to saltwater corrosion. So if a boat has these plates, inspect them for salt deposits and rust.

6. Discoloration Around the Bolts

Another telltale sign of a boat that has been in saltwater is brown staining on and around bolts. Check the bolts, especially those located on boat parts exposed to water, for signs of saltwater corrosion. Regularly lubricating or greasing bolts can prevent saltwater damage to bolts.

7. Rusty Boat Trailer or an Old Boat on a New Trailer

The boat trailer is highly prone to corrosion. So before you buy a boat, pay close attention to parts of the trailer, including the frame, brake rotors, and wheel bearings.

An old boat on a new trailer may also signify the vessel has been in saltwater. The previous trailer may have had extensive saltwater damage hence the replacement. So keenly inspect the boat for signs of rust and corrosion.

8. Rust on the Base Plate of the Ski Pylon

If the boat has a ski pylon, check if the base plate—typically made of stainless steel—has rust on the surface. Thoroughly cleaning the ski pylon after every boat ride in salt waters can help prevent corrosion. If this is not done or not done well, rust will begin to form.

9. Corroded Steering Cable Aluminum Support Tube

An aluminum tub supports the end of the boat’s steering cable before it attaches to the rudder or engine from the steering helm. People often overlook this cable when cleaning the boat after use in saltwater. Check the aluminum tube for signs of corrosion, such as a powdery white coating.

10. Surface Rust in the Bilge

Excess water caused by rough seas or untreated leaks collects in the bilge. Standing bilge saltwater accelerates rust formation on metal surfaces in the boat’s interior. 

A rusty bilge may therefore indicate previous boat use in saltwater. Ensure to check the bilge pump for rust as well.

If you need to replace the boat’s bilge pump, I recommend the MAXZONE Automatic Bilge Pump from Amazon. The pump is easy to install, doesn’t require a separate float switch, and automatically turns on when the water level rises and shuts off when water is removed.

11. Black or Dark Water Intake Grate

Exposure to salt water can cause a water intake grate to corrode. People ignore the intake grate when cleaning the boat and flushing the outboard motor after use in an ocean or sea. Consequently, salt buildup eventually discolors it.

If the boat’s intake grate is dark or black, you are most likely dealing with a vessel that has been in saltwater.

Sailboat on the ocean: saltwater will corrode a boat much quicker than freshwater.

12. The Carpet Has a Rough Texture

If the boat has a carpeted area, feel the texture of the carpet. If not cleaned thoroughly, salt crystals remain in the carpet, resulting in a rough, gritty texture.

Check also for unsightly white salt stains on the carpet. Additionally, when salt penetrates the boat carpet fibers, it causes them to wear out much faster. That’s because salt has an abrasive nature, as mentioned earlier.

Signs a Boat Has Been Used in Saltwater – Conclusion

Now that you know what to look for, you shouldn’t have trouble telling if a boat has been in salt water. If you’re considering buying a boat and the current owner is not forthcoming, the points in this article should help you prevent unknowingly buying a boat with a saltwater past, or at the very least it should give you the opportunity to negotiate a better price.

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