MG Duff 876604 Volvo Penta 120 Saildrive Ring Anode

MG Duff CM851983 Volvo Penta 876604 120 Saildrive Ring Anode – Zinc / Aluminium

The MG Duff CM851983Z and CM851983A are sacrificial ring anodes designed for compatible Volvo Penta 120 Saildrive installations. Both variants correspond to Volvo Penta OEM part number 876604 and provide galvanic corrosion protection for electrically connected underwater metallic components of the saildrive assembly.

The series is available in two sacrificial materials: zinc (CM851983Z) and aluminium (CM851983A). Both versions share the same dimensions and mounting configuration.

The anode measures 124 mm in length, 96 mm in width and 27 mm in height. It features two fixing holes spaced 73 mm between centres and a specified 6 mm stud size.

The zinc version weighs 0.49 kg, while the aluminium version weighs 0.24 kg.

Technical Specifications

Available Material Variants

Volvo Penta Saildrive Compatibility

The MG Duff CM851983 series is listed for the following Volvo Penta Saildrive models and configurations:

• 120 Series: 120, 120B, 120C, 120D, 120E
• S120: S120C
• MS25S Series: MS25S, MS25S-A, MS25S-R

The supplied Volvo Penta original part reference is 876604.

Compatibility should be checked against the existing anode, the saildrive model and the applicable Volvo Penta parts documentation. Model designations alone may not identify every installation configuration.

Ring Anode Dimensions and Mounting

The CM851983 series features a ring-style sacrificial anode with the following dimensions and fixing arrangement:

• Body length: 124 mm
• Width: 96 mm
• Height: 27 mm
• Number of fixing holes: 2
• Fixing-hole centre distance: 73 mm
• Stud size: 6 mm

The 73 mm measurement refers to the distance between the fixing-hole centres. It should not be confused with the overall width or length of the anode.

Both material variants have identical specified dimensions and mounting measurements, making the sacrificial material the primary choice between the two options.

Zinc and Aluminium Corrosion Protection

The MG Duff CM851983 series is available in two materials:

• Zinc – CM851983Z: Weighs 0.49 kg and is specified for sacrificial corrosion protection in saltwater applications.
• Aluminium – CM851983A: Weighs 0.24 kg and is specified for suitable saltwater and brackish-water applications.

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

Select the appropriate anode material according to the vessel's operating water conditions and Volvo Penta's corrosion protection recommendations.

Inspection and Replacement

Inspect the saildrive ring anode periodically as part of routine propulsion system maintenance. Replace it when the sacrificial material becomes significantly depleted, damaged or no longer securely attached.

Before installing the replacement:

• Confirm the Volvo Penta Saildrive model.
• Check the original part number 876604.
• Verify the dimensions of 124 × 96 × 27 mm.
• Confirm the two fixing holes and 73 mm centre distance.
• Check the specified 6 mm stud size.
• Inspect the mounting contact surfaces and follow the applicable Volvo Penta installation instructions.

Part Numbers and Cross-References

• MG Duff Zinc: CM851983Z
• MG Duff Aluminium: CM851983A
• Volvo Penta OEM: 876604
• Zinc Weight: 0.49 kg
• Aluminium Weight: 0.24 kg

Scope of Supply

1 × MG Duff Volvo Penta 120 Saildrive Ring Anode in the selected material:

• CM851983Z – Zinc; or
• CM851983A – Aluminium.

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