Zinc Rudder Anode 3-3/4″ CMT-R03

The CMT-R03 is a 3-3/4″ zinc rudder anode (R-3 style) designed to protect rudders and trim tabs from galvanic corrosion in saltwater environments. This two-piece pancake style anode clamps securely around the rudder surface, sacrificing itself to protect critical underwater metals.

Manufactured from high-purity zinc alloy, it delivers reliable corrosion protection and consistent performance in marine applications.

Key Features

• 3-3/4″ diameter rudder/trim tab anode
• Marine-grade zinc (saltwater optimized)
• Two-piece clamshell design with stainless hardware
• Dome-style profile to reduce drag
• Manufactured to MIL-spec alloy standards

Application / Compatibility

Designed for:

• Rudders
• Trim tabs
• Flat underwater surfaces

Common on:

• Inboard boats
• Sailboats
• Cruisers and sportfish vessels

Protects:

• Rudder plates
• Trim tabs
• Adjacent bonded underwater metals

Serial Number Fitment Notice

Always confirm:

• Diameter (3-3/4″)
• Thickness (~1/2″ per half)
• Mounting hardware and spacing

Correct sizing ensures proper contact and corrosion protection.

When This Part Needs Replacement

• Anode is 50% or more consumed
• Uneven wear or pitting
• Loss of thickness
• Routine haul-out inspection

Installation Notes

• Install on clean, bare metal surface
• Tighten evenly across both halves
• Do not paint the anode
• Inspect hardware regularly
• Replace before full depletion

Alternate / Superseded Part Numbers

• Camp Company: CMT-R03
• Martyr: CMR03
• Common references: R-3, R3
• Aluminum version: CMT-R03AL
• Magnesium version available for freshwater

Parts Desk Insight

The R-3 is the go-to size for smaller rudders and trim tabs. If you see uneven wear, its often a bonding issuenot the anode itself.

Shipping

Shipping: Ships same or next day for fast Canada wide shipping.