MG Duff 875815 Volvo Penta 280 / 290 Sterndrive Large Propeller Ring Anode

MG Duff CMV18 Volvo Penta 875815 280 / 290 Sterndrive Large Propeller Ring Anode – Zinc / Aluminium

The MG Duff CMV18Z and CMV18A are large propeller ring sacrificial anodes designed for compatible Volvo Penta 280 and 290 sterndrives. Both versions correspond to Volvo Penta original part number 875815.

These replacement anodes are available in zinc (CMV18Z) and aluminium (CMV18A). They provide sacrificial corrosion protection for electrically connected underwater metallic components of compatible Volvo Penta sterndrive assemblies.

The ring anode measures 120 mm in outside diameter, 61 mm in inside diameter and 34 mm in height. It features two fixing holes positioned on 61 mm centres, with a specified 8 mm stud size.

The zinc version weighs 0.73 kg, while the aluminium version weighs 0.29 kg. Both materials share the same specified mounting dimensions.

Technical Specifications

Available Material Variants

The zinc version is also referenced as CMV18 in the supplied product information. The material-specific MG Duff part numbers are CMV18Z for zinc and CMV18A for aluminium.

Volvo Penta Sterndrive Compatibility

The MG Duff CMV18 series is listed for compatible Volvo Penta 280 and 290 sterndrive installations, including the following model references:

The aluminium variant is additionally described for compatible Volvo Penta 280 / 290 single-propeller drive applications.

Compatibility should be confirmed against Volvo Penta OEM part number 875815 and the original anode mounting dimensions. Individual drive configurations may differ.

Large Propeller Ring Anode Dimensions

The CMV18 series features a ring-shaped sacrificial anode body intended for the corresponding propeller area of compatible Volvo Penta sterndrives.

• Outside diameter: 120 mm
• Inside diameter: 61 mm
• Overall height: 34 mm
• Number of fixing holes: 2
• Fixing-hole centre distance: 61 mm
• Stud size: 8 mm

The 61 mm inside diameter and 61 mm fixing-hole centre distance are separate measurements and should not be confused when checking the original anode.

Both material variants use the same stated dimensions and mounting configuration.

Zinc and Aluminium Corrosion Protection

The MG Duff CMV18 series offers two sacrificial anode materials:

• Zinc – CMV18Z: Weighs 0.73 kg and is commonly used for galvanic corrosion protection in saltwater marine environments.
• Aluminium – CMV18A: Weighs 0.29 kg and is used in suitable marine corrosion protection systems, including saltwater and certain brackish-water conditions.

When correctly installed with suitable electrical continuity to the metallic components requiring protection, the sacrificial anode material corrodes preferentially, helping reduce galvanic corrosion of connected underwater sterndrive parts.

Select the appropriate material according to operating water conditions and Volvo Penta's recommendations for the specific propulsion system.

Inspection and Replacement

Inspect the propeller ring anode periodically during routine Volvo Penta sterndrive maintenance. Replace it when the sacrificial material becomes significantly depleted, damaged or no longer securely attached.

Before fitting a replacement:

• Confirm the Volvo Penta drive model and original part number 875815.
• Check the outside diameter of 120 mm and inside diameter of 61 mm.
• Verify the 34 mm overall height.
• Confirm the two fixing holes and their 61 mm centre distance.
• Check the specified 8 mm stud size.
• Inspect the mounting surfaces and follow the applicable Volvo Penta installation instructions.

Part Numbers and Cross-References

• MG Duff Zinc: CMV18Z
• Additional Zinc Reference: CMV18
• MG Duff Aluminium: CMV18A
• Volvo Penta OEM: 875815
• Zinc Weight: 0.73 kg
• Aluminium Weight: 0.29 kg

Scope of Supply

1 × MG Duff Volvo Penta Large Propeller Ring Anode in the selected material:

• CMV18Z – Zinc; or
• CMV18A – Aluminium.

Mounting hardware inclusion is not specified in the supplied product information.