Home / Anodes:Cathodic / MIL-DTL-18001L Cathodic Zinc Anode Type ZEP Style B
Product Code: 8001B
MIL-DTL-18001L Cathodic Zinc Anode Type ZEP Style B
Lead-freeMIL-DTL-18001LCircular Form 2" to 11" DiameterSymmetric Current Distribution3/8" to 3/4" IPS Bolt-On Mount
MIL-DTL-18001L Type ZEP Style B round zinc anodes, 2" to 11" diameter, 1" thick. Configurations include 3/8" or 1/2" IPS. Used for cathodic protection of steel hulls and tanks.
MIL-DTL-18001L Type ZEP Style B Zinc Anodes are circular plate-form sacrificial zinc anodes manufactured by Belmont in seven standard diameters from 2″ to 11″ all at 1″ nominal thickness for cathodic protection of steel ship hulls, ballast tanks, and underwater steel structures. The circular form provides uniform current distribution in all radial directions from the anode center making Style B particularly effective for protecting circular hull penetrations, tank fittings, and structural nodes where current must radiate symmetrically. Each anode is equipped with either 3/8″ or 1/2″ IPS threaded inserts for bolt-on installation to threaded studs welded to the protected structure – the 11″ diameter piece uses two 3/4″ IPS inserts for increased structural support at the larger size. The range of diameters from 2″ to 11″ provides flexibility to match anode mass to the current demand of the specific protected area. Zinc alloy conforms to MIL-DTL-18001L composition.
Available Forms
2" Diameter x 1" Thick Circle, 3" Diameter x 1" Thick Circle, 4" Diameter x 1" Thick Circle, 5" Diameter x 1" Thick Circle, 6" Diameter x 1" Thick Circle, 9" Diameter x 1" Thick Circle, 11" Diameter x 1" Thick Circle
Product Code
8001B
Technical Info
Thermal Properties
Melting Point (Solidus)787°F (419°C)
Melting Point (Liquidus)787°F (419°C)
Physical Properties
Density (imperial)0.258 lbs/in³
Density (metric)7.13 g/cm³
Primary ElementsZn
SpecificationMIL-DTL-18001L
Lead FreeYes
Key Features
Circular Form 2" to 11" DiameterSymmetric Current Distribution3/8" to 3/4" IPS Bolt-On Mount
Nominal Composition
99.55% Zn
Bal
Frequently Asked Questions
Common technical inquiries regarding MIL-DTL-18001L Cathodic Zinc Anode Type ZEP Style B
A hull penetration (shaft seal, sea chest, transducer fitting) is a circular feature that creates a radially symmetric current demand - the bare metal at the penetration boundary draws current equally in all directions from the center. A circular anode centered over the penetration matches this symmetric demand geometry providing equal protection distance in all directions and preventing the edge effects that occur when a rectangular anode is centered over a circular feature. The circular anode also avoids the current concentration at corners that accelerates preferential dissolution of rectangular anodes.
For a 4" sea chest or through-hull fitting a 6" or 8" diameter Style B anode is typically specified - the anode diameter should be 1.5-2 times the fitting diameter to ensure the protection current radiates beyond the immediate fitting perimeter to cover adjacent hull plating that may be galvanically coupled to the bronze or stainless fitting. The 6" anode (approximately 5-6 lbs) provides a typical 1-2 year service interval; the 8" anode provides extended life for vessels with longer drydocking intervals or higher corrosion environments.
Yes - both Style A and Style B use standard IPS threaded inserts (3/8", 1/2", 3/4") that are compatible with the same threaded stud sizes welded to tank interiors. The choice between Style A (square/rectangular) and Style B (circular) within a tank is based on geometry - Style A is preferred for flat plating runs and large wall areas where rectangular coverage is more efficient while Style B is preferred near circular fittings, pipes, and structural nodes. Both types are intermixed in practical cathodic protection designs to match anode geometry to the local protection requirement.
MIL-DTL-18001L Type ZHC-23 zinc hull anode, 1-1/4″ x 6″ x 12″, 23 lbs, with core strap and 2 recessed bolt holes. Used for ship hull cathodic protection.
MIL-DTL-18001L Class 2 Type ZRN zinc rods with full mill certification. Three diameters in 72″ lengths. Used as pencil anode stock and for marine cathodic protection rod applications.
