Martyr CMDIVERA Hull Plate Anode — Aluminum | ½” × 6” × 12” | Salt & Brackish Water

Martyr CMDIVERA — Aluminum Hull Plate Anode | ½” × 6” × 12” | Salt & Brackish Water

Part Number: CMDIVERA (SKU: 194-CMDIVERA)
Brand: Martyr Anodes
Official Product Type: Hull Plate Sacrificial Anode — Aluminum
Common Name: Diver’s Dream Hull Anode
Dimensions: ½” × 6” × 12” (approx. 12.7 mm × 152 mm × 305 mm)
Supersedes: No known superseded number
Replaced By: CMDIVERA is the current active part number

The Martyr CMDIVERA is a large-format aluminum hull plate anode designed for direct mounting to a boat’s hull below the waterline. Known in the industry as the “Diver’s Dream,” this anode is sized and shaped for easy underwater installation and replacement by a diver without hauling the vessel. The flat plate profile bonds flush to the hull and provides broad-area cathodic protection for steel, aluminum, and other metal hull structures. Aluminum alloy construction makes this the correct choice for salt and brackish water environments.

Compatible Applications

• Steel and aluminum boat hulls requiring broad-area cathodic protection
• Commercial vessels, workboats, and larger recreational hulls
• Vessels kept in the water year-round where diver-serviceable anodes are preferred
• Any hull surface in salt or brackish water requiring a large flat-plate anode
• Supplemental hull protection alongside drive and shaft anodes

System & Location

Cathodic protection system — hull-mounted plate anode. Mounts flush to the hull below the waterline using through-bolts or studs. The flat profile minimizes drag and allows installation in areas where a streamlined anode profile is important. Designed to be replaced in-water by a diver.

Anode Material Guide

• Aluminum (this anode): Salt water & brackish water ✓
• Zinc: Salt water — see Martyr CMDIVER Hull Anode — Zinc
• Magnesium: Fresh water only — see Martyr CMDIVER Hull Anode — Magnesium

Kit Contents

• One (1) aluminum hull plate anode, ½” × 6” × 12”
• Mounting hardware not confirmed included — verify at time of order; reuse existing studs or through-bolts if not supplied

Dimensions & Weight

• Dimensions: ½” × 6” × 12” (12.7 mm × 152 mm × 305 mm)
• Weight: Approx. 1,100 g / 2.43 lb (estimated)

Service Interval

Inspect at every haul-out or have a diver inspect annually if the vessel is kept in the water. Replace when the anode has been consumed to approximately 50% of its original mass. The large size of this anode means it typically lasts longer than smaller hull anodes, but depletion rate depends on water conditions, current density, and the amount of bare metal being protected.

Installation Notes

• Mount flush to the hull using through-bolts or studs — ensure direct metal-to-metal contact between the anode and the hull
• Do not apply paint, bedding compound, or sealant between the anode and the hull surface
• Bare metal contact is essential for the anode to function correctly
• Torque fasteners securely — a loose anode will not make proper electrical contact and may be lost
• Use aluminum anodes in salt and brackish water only — not effective in fresh water

Technical FAQ

Q: Why is this called a “Diver’s Dream”?
The name refers to the anode’s design for easy in-water replacement by a diver. The flat plate profile and straightforward bolt-on mounting make it practical to swap without hauling the vessel.

Q: Why aluminum instead of zinc for salt water?
Aluminum anodes are more electrochemically efficient than zinc in salt and brackish water, providing more protection per kilogram of anode material. They are the preferred choice for most salt and brackish water hull applications.

Q: Can this anode be used in fresh water?
No. Aluminum anodes do not perform correctly in fresh water. Use the magnesium version (CMDIVERM) for fresh water applications.

Q: How many of these anodes does my hull need?
The number of hull anodes required depends on the hull material, surface area of bare metal, and water conditions. A marine surveyor or corrosion specialist can calculate the correct anode mass for your vessel.

Related Parts

• Martyr CMDIVER Hull Anode — Zinc (½” × 6” × 12”)
• Martyr CMDIVER Hull Anode — Magnesium (½” × 6” × 12”)

Parts Desk Insights

The CMDIVER is the go-to hull plate anode for commercial operators and liveaboard owners who keep their vessels in the water year-round and rely on divers for routine anode service. The large surface area makes it effective for protecting significant stretches of bare steel or aluminum hull. The most common question we get is how many are needed — that depends on the hull and water conditions, and for working vessels it’s worth getting a proper corrosion survey to size the anode system correctly rather than guessing. For salt and brackish water, aluminum is the better long-term value over zinc.