Martyr CMX13 Zinc Streamline Shaft Anode – Large Diameter | Stainless Allen Screw | Saltwater
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Martyr Zinc Streamline Shaft Anode — CMX13 | Saltwater
A large-diameter zinc streamline sacrificial shaft anode for inboard propeller shafts in saltwater environments. The streamline (teardrop) profile reduces hydrodynamic drag compared to a standard round shaft anode, making it a preferred choice for performance-conscious inboard installations on larger vessels. Secured with a stainless steel Allen head screw for a clean, tool-accessible installation.
Note: Confirm your shaft diameter against the CMX13 specification before ordering. This is a large-diameter unit in the CMX streamline series — verify the shaft diameter matches your installation.
Zinc is the traditional choice for saltwater environments. If you operate in freshwater or brackish water, a magnesium or aluminum alloy shaft anode is the correct choice for those water types.
Part Information
- Part Number: CMX13
- Brand: Martyr Anodes
- Anode Material: Zinc
- Anode Type: Streamline Shaft Anode
- Fastener: Stainless steel Allen head screw
- Best Use: Saltwater environments; large-diameter inboard shafts
Compatible Applications
- Large-diameter inboard propeller shafts — confirm shaft diameter before ordering
- Applications where reduced hydrodynamic drag is preferred over a standard round anode
- Saltwater operating environments
CMX Large-Diameter Streamline Series
- CMX13 (this part) — large-diameter zinc streamline shaft anode (~1,500 g)
- CMX12 — large-diameter zinc streamline shaft anode (~1,800 g)
Related Streamline Shaft Anodes
- Martyr CMX02 Zinc Streamline Shaft Anode – 7/8” — smaller zinc streamline anode
- Martyr CMX02AL Aluminum Streamline Shaft Anode – 7/8” — aluminum option for saltwater and brackish water
- Magnesium Streamline Shaft Anode – 7/8” — magnesium option for freshwater
- Aluminum Streamline Shaft Anode 1” — CMT-X03AL
- Aluminum Streamline Shaft Anode 1-1/8” — CMT-X04AL
- Zinc Streamline Shaft Anode 1-1/2” — CMT-X07
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 CMX13 is a large-diameter streamline shaft anode suited to bigger inboard vessels where shaft diameter and drag reduction both matter. It is slightly smaller than the CMX12 — confirm your exact shaft diameter against both specifications before ordering. The streamline profile sheds water cleanly and creates less turbulence than a round anode at speed, but provides slightly less sacrificial mass than a full-round anode of the same shaft diameter. Zinc is a reliable saltwater choice, but if your boat moves between fresh and salt water, an aluminum alloy streamline anode is the more versatile option. 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.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.