Welcome to PROMT Parts, your reliable distributor of high-quality and cost-effective marine cathodic protection solutions. Our Martyr Anodes offer exceptional performance in safeguarding boats, marine structures, and boat equipment from corrosion. Crafted from a specialized alloy based on the US Mil Spec and composed of high-purity metals, our Martyr Anodes, commonly referred to as "Boat Zincs," provide unparalleled protection in saltwater, brackish water, and freshwater environments.

Saltwater is a harsh environment for metals on your boat. Two main types of corrosion can lead to costly repairs and shorten your boat's lifespan: galvanic corrosion and stray current corrosion.

Galvanic Corrosion: The Silent Threat

• What it is: Galvanic corrosion occurs when two dissimilar metals are in electrical contact with saltwater, which acts as an electrolyte. This creates a weak electrical current that causes one metal to corrode faster (anode) while protecting the other (cathode).
• The Culprit: Common culprits on boats include bronze fittings connected to stainless steel shafts or aluminium hulls paired with steel outdrives.
• The Solution: To combat this, boats use sacrificial anodes. These anodes, typically made from zinc, aluminium or magnesium, are designed to corrode preferentially, protecting your boat's critical components.

The Importance of Proper Anode Selection and Maintenance: For optimal protection, it's crucial to choose the right anode type and size for your boat and water conditions. We offer a variety of anodes to suit different needs. Regularly inspecting and replacing anodes as they wear away is essential for maintaining corrosion protection. Our Silver/Silver Chloride Reference Electrodes are specifically designed for measuring and confirming your Anodes are providing the right level of Cathodic Protection for your boat.

Stray Current Corrosion: Electrolysis

• What it is: Stray current corrosion occurs when electrical current leaks from your boat's electrical system or from external sources like marinas or improperly grounded shore power. This current travels through saltwater, accelerating corrosion on underwater metals like propellers, shafts, and rudder fittings.
• The Danger: Stray current corrosion, not electrolysis, can rapidly erode metals, destroying propellers, shafts, and even corroding holes into aluminium hulls.
• The Culprit: Common culprits on boats include wiring that comes in contact with water, like bilge pump wiring or underwater lights. If non-waterproof crimps are used to join wires, when submerged in water, these connectors allow stray currents to flow between metals in contact with the water, causing corrosion.
• The Solution: Silver Chloride Reference Electrodes By using silver chloride reference electrodes, you can monitor stray current and take corrective actions to prevent damage. Our high-quality silver chloride reference electrodes provide accurate and reliable measurements for effective corrosion control.

By using a combination of sacrificial anodes and stray current monitoring with silver chloride reference electrodes, you can significantly reduce corrosion and extend the life of your boat. 

Prevent marine and offshore corrosion effectively with Zinc or Aluminium Anodes, the efficient solution for cathodic protection. Saltwater, akin to a chemical soup, gradually causes a steel hull to rust away due to the corrosive nature of salt ions. Zinc anodes, known for their high activity on the electrolysis chart, sacrificially corrode before the steel does.

Replacing worn-out anodes is far easier and exponentially more affordable than replacing an entire steel hull. Regular inspection and replacement of boat anodes are crucial to prevent hull damage. Sacrificial Anodes, made of metals more reactive than the ship's body and systems, are electrically linked to the ship's hull, shielding it and its components. The name "Sacrificial Anodes" reflects their protective role.

Zinc, commonly used due to its higher voltage in water, ensures that the current flows more readily from it than from the propeller. Anodes are bolted directly onto the boat's hull, completing the electrical circuit. At PROMT Parts, we offer a range of Hull Anodes to safeguard your investment effectively.

Shop for Hull Anodes

To achieve optimal protection, the surface area of an anode must be proportionate to the surface it aims to protect. Installing shaft anodes can be challenging due to shaft design. Here are essential tips for proper installation:

• Ensure a clean shaft surface free from debris.
• Avoid painting the anode.
• Accurately measure the shaft diameter to select the appropriate anode size.
• Leave a 10mm space between the anode and the cutlass bearing.
• Install additional anodes if necessary to protect the required surface area.
• Use the same alloy type across all anodes and ensure it is suitable for the water type.
• Secure bolts in place using threadlocker.

Shop for Shaft and Propeller Anodes

For stainless steel rudders, it is recommended to fit a disc anode on each side. PROMT Parts offers various options ranging from heavy-duty to regular sizes for this purpose. Use stainless steel fittings whenever possible, or zinc galvanized studs as an alternative, ensuring they match the stainless steel grade. If using pairs of discs, check the length of the fixing bolt to ensure it passes through the rudder adequately.

For trim tabs, fit anodes on the top side, and consider increasing the anode size if the surface area exceeds 1 square meter. Remember that surface area, in addition to weight, is crucial. You can verify your configuration using a multi-meter.

Choose PROMT Parts for high-quality marine anodes and experience effective cathodic protection for your valuable investment.

Shop for Rudder and Trim Tab Anodes

Cathodic protection is an electrochemical process that thwarts the natural corrosion reaction of metals within specific environments. This is achieved by introducing a more potent electrochemical cell than the existing corrosion cell. Sacrificial anodes are strategically placed or bonded to the metal requiring protection. As the anode material possesses higher electrical potential compared to the protected metal, it adopts a cathodic role, leading to the corrosion of the anode itself. In a well-implemented Martyr Cathodic Protection System, the sacrificial anode is the sole component that undergoes corrosion and can be easily replaced. The quantity and size of anodes are determined by factors like material type and the surface area in need of safeguarding.

Bonding involves connecting the anode to a distant metal element, such as a propeller shaft or rudder stock. Ensuring the integrity of this bonding is vital for the effectiveness of the cathodic protection system.

The selection of an appropriate cathodic protection system hinges on various factors including the vessel's operating environment, dimensions, construction type, and the interval between maintenance or slipping periods.

Can I Test My Anodes?

Absolutely, evaluating whether your vessel and valuable submerged metals are adequately shielded holds utmost importance in your corrosion protection strategy. Neglecting anode testing leaves the protection of your boat and equipment to guesswork. Without effective cathodic protection, underwater metals such as Sterndrives can deteriorate within weeks or months.

PROMT Parts offers cost-effective high precision reference electrodes, facilitating straightforward verification of your anodes' functionality. Do not overlook this critical step in your battle against corrosion.

Click here : how to test anodes