Martyr CMC02 Zinc Limited Clearance Shaft Anode – Stainless Allen Screw | Saltwater

Martyr Zinc Limited Clearance Shaft Anode — CMC02 | Saltwater

A zinc sacrificial shaft anode designed for propeller shaft installations where a standard round anode won’t fit due to tight clearances near the hull, strut, or cutlass bearing. The CMC02 uses the same limited clearance profile as the CMC01 but is a larger, heavier unit suited to bigger shaft diameters. Secured with a stainless steel Allen head screw for a clean, tool-accessible installation.

Zinc is the traditional choice for saltwater environments. If you operate in freshwater, a magnesium alloy shaft anode is the correct choice for that water type.

Part Information

• Part Number: CMC02
• Brand: Martyr Anodes
• Anode Material: Zinc
• Anode Type: Limited Clearance Shaft Anode
• Fastener: Stainless steel Allen head screw
• Best Use: Saltwater environments with tight shaft clearances; larger shaft diameters

Compatible Applications

• Propeller shafts with limited clearance to hull, strut, or cutlass bearing
• Inboard and shaft-drive installations where standard round shaft anodes will not fit
• Larger shaft diameter applications — confirm shaft diameter compatibility before ordering
• Saltwater operating environments

CMC Series — Choosing the Right Size

• CMC01 — smaller limited clearance shaft anode (lighter duty / smaller shaft diameter)
• CMC02 (this part) — larger limited clearance shaft anode (heavier duty / larger shaft diameter)

Related Shaft Anodes

• Aluminum Streamline Shaft Anode 1” — CMT-X03AL — streamline profile for reduced drag
• Zinc Streamline Shaft Anode 1-1/2” — CMT-X07 — streamline zinc shaft anode
• Zinc Shaft Anode 4” — CMT-X17 — larger zinc shaft anode
• Zinc Shaft Anode MDX-5 1-1/4” — standard profile zinc shaft anode
• Zinc Shaft Anode MDX-7 1-1/2” — standard profile zinc shaft anode

Service Interval

Inspect shaft anodes at every haulout and replace when worn to approximately 50% of original size. Shaft anodes can deplete faster than hull or drive anodes due to their direct exposure on the rotating shaft — inspect more frequently on vessels kept in high-galvanic marina environments.

Parts Desk Insights

The CMC02 is the larger of the two CMC limited clearance shaft anodes — if you’re unsure which size fits your shaft, the key measurement is the shaft diameter and the available clearance between the shaft and the nearest fixed structure (strut, hull, or cutlass bearing housing). If you have the space for a standard round profile, a full-round anode provides more sacrificial mass and longer service life between replacements. The stainless Allen screw makes installation and removal straightforward, but always confirm the anode has solid metal-to-metal contact with the shaft — a loose fit or painted shaft surface will prevent the anode from working. If you’re unsure whether CMC01 or CMC02 is the right fit, compare the shaft diameter against both part specifications before ordering.