Anodic Protection and Sacrificial Zincs | How Saltwater Care Protects Your Bennington Pontoon and Preserves Its Value

The first time you trailer your Bennington after a long weekend in the salt, and you spot white powder creeping across the aluminum pontoons, you realize—saltwater doesn’t play nice with metal.

TL;DR: Saltwater is surprisingly good at eating away at aluminum pontoons, engine parts, and metal hardware. But here’s the good news: a simple, low-cost system called sacrificial anodes (often called “zincs”) takes the hit for your boat. These small metal blocks corrode on purpose so your expensive Bennington parts don’t have to. This post explains how anodic protection works, which anodes to use for your water type, where to install them, and how to keep your Bennington pontoon boats looking and running great for years—even if you boat in the ocean.

Key Takeaways:

• Sacrificial anodes corrode instead of your boat’s aluminum tubes, engine, and prop
• Different water types (salt, brackish, fresh) require different anode metals—zinc for salt, aluminum for brackish, magnesium for fresh
• Replace anodes when they shrink to 50% of original size—waiting too long risks real damage
• Never paint over anodes—they need bare metal contact with water to work
• A proper saltwater routine includes rinsing, flushing the engine, and inspecting anodes after every trip

Understanding Galvanic Corrosion: Why Saltwater Attacks Your Bennington Pontoon

Here’s a science fact that matters to your wallet. When two different metals touch each other in saltwater, they create a tiny battery. The saltwater acts like the acid in a car battery, and electricity starts flowing between the metals . One metal gives up tiny particles to the other. That’s galvanic corrosion—and it eats away at the softer metal over time .

Your Bennington pontoon has lots of different metals. The pontoons are aluminum. The engine has stainless steel, bronze, and other alloys. The propeller might be stainless or aluminum. The bolts and fittings mix it up too. In saltwater, all those different metals want to react with each other. The aluminum pontoons are usually the ones that lose the battle .

Have you ever noticed white, chalky spots on metal parts after boating in saltwater? That’s corrosion已经开始.

The “Nobility” Scale of Metals

Think of metals like a social ladder. Some metals are “noble” (fancy and resistant to corrosion). Others are “active” (less fancy and quick to corrode). Here’s how they stack up, according to Bennington’s own manual :

The farther apart two metals are on this list, the faster the corrosion happens. Aluminum and stainless steel? Pretty far apart. That’s why your aluminum pontoons need protection from stainless bolts and fittings.

Ever wonder why boats left in saltwater for years look like they have metal “rust” even though aluminum doesn’t technically rust? Now you know—it’s galvanic corrosion.

How Sacrificial Anodes Work: The Simple Science of Taking One for the Team

A sacrificial anode (often just called a “zinc”) is a small block of metal attached to your boat underwater. It’s made from a metal that’s even more “active” than aluminum . Think of it as the bodyguard for your pontoon.

Here’s what happens: When galvanic current tries to flow, it attacks the anode first because the anode metal is less noble than your boat’s aluminum . The anode slowly dissolves, crumbles, or turns into white powder. Meanwhile, your expensive aluminum tubes, engine lower unit, and propeller stay perfect.

This is not a theory. Every Bennington owner who boats in salt or brackish water relies on this system. The manual says it clearly: “Less noble metal anodes are used to purposefully ‘sacrifice’ themselves, thereby protecting the more noble metals” .

Isn’t it amazing that a $30 block of metal can save you from a $5,000 pontoon replacement?

“Sacrificial anodes are important and require periodic inspection for deterioration. Replace the anode when it is less than 50% of its original size.” — Bennington Owner’s Manual

Where Anodes Go on a Bennington Pontoon

Bennington installs anodes in several places, depending on your model and whether you have the Saltwater Series package :

• On the transom (the back of the boat, near the engine mount)
• On the bottom of each pontoon tube (usually near the rear)
• On the engine itself (your outboard came with anodes from the factory)
• On trim tabs (if equipped)
• On boarding platform supports (the brackets holding your swim deck)
• On underwater gear like heat exchangers and cooling jackets

Some owners add extra anodes. One Florida Bennington owner added three zinc anodes—one per pontoon tube—to protect his 23 Q Series used in saltwater .

Safety reminder: Always check your anodes before launching. A missing or fully corroded anode means your boat has no protection.

Choosing the Right Anode Metal for Your Water Type

This is where people get confused. Not all anodes are the same. Use the wrong metal, and your anodes won’t work—or worse, they’ll cause problems.

The rule is simple: Match the anode metal to your water type .

Here’s the critical warning from Bennington’s manual: “Zinc and aluminum anodes left in fresh water or zinc anodes used in brackish water will become covered with white oxide which effectively stops the sacrificial process and exposes the underwater gear to damage” .

That white coating? It’s like putting a plastic bag over the anode. No water contact means no protection.

Did you buy your Bennington used and don’t know what anodes are installed? Pull one off and look—or ask a dealer to check.

Real-World Example: Brackish Water Confusion

One Bennington owner on the forum asked whether his factory anodes were zinc or aluminum because he boats in brackish water . Smart question. Another owner confirmed that Bennington’s Saltwater Series boats come with the correct anodes for saltwater—but if you’re in brackish, you might need aluminum instead of zinc .

Bottom line: If you’re not sure, replace with aluminum. Aluminum anodes work in both salt and brackish water. Zinc only works in full salt.

The Evolution of Bennington Boats and Saltwater Protection

Bennington didn’t always focus on saltwater. But as pontoon boats got faster and more capable, owners started taking them to the coast. Here’s how the company adapted:

How to Maintain Your Anodes and Prevent Corrosion

Inspection Schedule

Check your anodes every time you take the boat out of the water. Bennington says to replace them when they’ve deteriorated 50% or more . If an anode looks like a crumbling sponge or has shrunk noticeably, swap it.

Here’s a trick: Take a photo of your anodes when new. Compare every few months. You’ll see the difference.

Do NOT Paint Anodes

This is the most common mistake. Owners paint their anodes to make them “look nice” or match the boat. Don’t do it. Bennington’s manual is clear: “Do not paint sacrificial anodes. Bottom paints/sealants on anodes will block the sacrificial process and expose the underwater gear to damage” .

The same goes for the anodes on your engine. They need bare metal contact with water.

Rinse Everything After Saltwater Use

Anodes do their job, but they’re not magic. You still need to wash your boat. Bennington recommends :

• Rinse the hull and deck with fresh water immediately after saltwater use
• Flush the engine cooling system for at least 5 minutes (check your engine manual)
• If you trailer your boat, flush saltwater from between the bunks and pontoons
• Allow the boat to dry completely before covering (covering wet boat = mildew)
• Wax the hull monthly if used primarily in saltwater
• Apply corrosion inhibitor to all hardware

One experienced boater noted: “A good rinse-off as soon as I get back to the dock keeps saltwater related problems to a minimum” .

Have you ever skipped the rinse because you were tired after a long day? Your boat remembers.

Saltwater Series vs. Standard Models

Bennington offers a Saltwater preparation package on many models. According to forum discussions, this package includes :

• Sealed lifting strakes (prevents saltwater and marine life from getting trapped inside)
• Additional anodes (brackets welded to each pontoon tube)
• Anti-fouling paint (optional, applied by dealer)

One owner who bought a freshwater Bennington and moved to Florida added three zinc anodes himself . Another noted that even without the factory Saltwater Series, you can add anodes as long as your pontoons have mounting brackets .

Tip: If your Bennington didn’t come with anode brackets, ask a dealer about welding them on or using clamp-on anodes.

Real-World Impact: What Happens Without Anodes?

Let me paint a picture. A pontoon boat left in saltwater without anodes will start showing damage in months, not years.

• The aluminum pontoons develop white, powdery corrosion (aluminum oxide)
• Pitting appears—small holes that weaken the metal
• The engine lower unit corrodes around the prop shaft
• Stainless steel bolts cause accelerated corrosion of surrounding aluminum
• The boat’s value drops dramatically

One forum user described seeing pontoons “turn black” after two months in fresh water without proper protection . Saltwater is even faster.

Safety reminder: Corroded pontoons can fail suddenly. A hole in a pontoon tube means your boat loses buoyancy. Don’t risk it.

Comparison: Anode Types and Where to Buy

Here are real anode options for Bennington pontoon boats. Prices and availability vary by dealer.

Pro tip: Buy anodes in bulk. They’re consumables—you’ll need replacements every season or two depending on water conditions.

Anode Lifespan by Water Type

The chart below shows approximately how long a typical zinc anode lasts in different water conditions. Remember: Replace at 50% deterioration, not when completely gone.

Note: Actual lifespan varies based on water salinity, temperature, nearby boats, and shore power connections.

Frequently Asked Questions

What are sacrificial anodes on a Bennington pontoon?
Small metal blocks attached underwater that corrode on purpose to protect your boat’s aluminum and engine parts from galvanic corrosion.

How often should I replace anodes on my Bennington?
Inspect every time you trailer the boat. Replace when anodes are 50% deteriorated—usually every 6–12 months in saltwater.

Can I use zinc anodes in freshwater?
No. Zinc anodes in freshwater develop a white coating that stops them from working . Use magnesium for freshwater.

Does Bennington offer a saltwater package?
Yes. The Saltwater Series includes sealed lifting strakes and additional anodes. Ask your dealer about adding it to new orders .

How do I know what type of anode my Bennington needs?
Match the metal to your water: Zinc for salt, Aluminum for brackish, Magnesium for fresh. Check your owner’s manual or ask a dealer.

Can I add anodes to a Bennington that didn’t come with them?
Usually yes. Some pontoons have factory brackets. If not, you can weld brackets or use clamp-on anodes .

Do I need anodes if I only boat in freshwater lakes?
Yes, but use magnesium anodes. Freshwater still causes galvanic corrosion, especially if your marina has shore power or other boats nearby.

What’s Your Experience with Saltwater Boating?

Anodic protection isn’t glamorous. You won’t see it in the brochure next to the premium vinyl seating or the digital helm display. But it’s the reason your Bennington pontoon can last 20 years instead of 5. Those little blocks of metal work silently underwater, taking the hit so you don’t have to.

If you’ve boated in salt or brackish water, you’ve probably got a story—a close call, a lesson learned, or a tip that saved your boat. Share it below.

What’s your favorite Bennington boat feature or on-the-water experience? Share your thoughts in the comments below.

References:

• Bennington Marine – Tips for Pontoon Boating on Saltwater
• Bennington R Series Owner’s Manual (Pages 185-187)
• Club Bennington Forum – Saltwater vs Freshwater Pontoons
• Club Bennington Forum – Zinc Anode Discussion