Martyr CMX09M Magnesium Streamline Shaft Anode – 2" Shaft | Stainless Allen Screw | Freshwater
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Martyr CMX09M Magnesium Streamline Shaft Anode
The correct sacrificial shaft anode for 2" prop shafts in freshwater. Magnesium is the only alloy with sufficient electrochemical activity to protect your shaft in low-conductivity freshwater — zinc and aluminum anodes go passive in freshwater and provide little to no galvanic protection. The streamlined, hydrodynamic profile keeps drag to a minimum, and the stainless steel Allen head screw holds the anode firmly in place all season.
The 2" shaft diameter is found on large inboard vessels, heavy twin-screw cruisers, commercial workboats, and trawlers operating in freshwater lakes and rivers.
Compatible Applications
- 2" (51mm) diameter prop shafts
- Freshwater use only (lakes, rivers, reservoirs)
- Large inboard and heavy twin-screw vessels
- Commercial workboats and trawlers in freshwater
- Replaces OEM shaft anodes on most standard 2" shaft configurations
Specifications
- Part Number: CMX09M
- SKU: 194-CMX09M
- Material: Magnesium alloy (sacrificial)
- Shaft Diameter: 2" (51mm)
- Fastener: Stainless steel Allen head screw
- Profile: Streamlined / hydrodynamic
- Best For: Freshwater only
- Weight: ~370 g
Also Available In
- CMX09 – 2" Zinc (saltwater)
- CMX09AL – 2" Aluminum (saltwater & brackish)
Adjacent Sizes – Magnesium
- CMX08M – 1-3/4" Magnesium Shaft Anode
- CMX10M – 2-1/4" Magnesium Shaft Anode
- CMX07M – 1-1/2" Magnesium Shaft Anode
Parts Desk Insights
The CMX09M is the right anode for any 2" shaft running in freshwater — a specialty size found on large twin-screw inboards, commercial vessels, and trawlers that operate on inland waterways and Great Lakes routes. This is one of the rarest sizes in the magnesium shaft anode lineup and is almost never stocked at local marine retailers. Order well ahead of your haulout date.
Zinc anodes are frequently installed on freshwater commercial vessels by mistake, particularly when the vessel was previously used in saltwater or when a yard installs whatever is on hand. Zinc provides essentially no galvanic protection in freshwater — if you’re seeing corrosion on a freshwater vessel with zinc shaft anodes, switching to magnesium is the fix. For saltwater or brackish water, use the CMX09AL aluminum version for coastal and mixed-salinity conditions, or the CMX09 zinc version for open-ocean saltwater.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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.