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ZHB Zinc Hull Slab Anode — Brass Straps
ZHB Zinc Hull Slab Anode — Brass Straps
Quoted on request. Price depends on the steel market and freight to your port. Tell us your port and specification and we will quote it delivered.
Contact Us For A QuoteZHB Zinc Hull Slab Anode — Brass Straps
The hull slab in the brass-strap form, to the same geometry as the ZHS-23. Specified where a non-ferrous strap is wanted at the fixing.
Zinc sacrificial anode to MIL-DTL-18001L, type ZHB — hull slab, brass straps. Quoted on request.
Sizes and weights
| Type | Size | Minimum weight | Spec figure |
|---|---|---|---|
| ZHB-23 | 23 lb nominal — 9.7 kg (21.5 lb) minimum | 9.7 kg (21.5 lb) | Fig 1 |
These are the minimum weights set by MIL-DTL-18001L, not the nominal. A ZHS-23 carries a 21.5 lb minimum, not 23 lb — the number in the designation is nominal.
Full dimensions, in inches and millimetres together, are on the specification drawing in the images above — that drawing is the only place those dimensions exist in both units.
Alloy and water
MIL-DTL-18001L is a zinc specification, supplied to ASTM B418 Type I — the alloyed seawater grade whose composition is written to meet MIL-A-18001K. That is why every supplier's datasheet claims to "meet or exceed military specification".
For fresh water zinc is the wrong alloy: use magnesium to ASTM B843, or zinc to ASTM B418 Type II, the high-purity grade for fresh and buried service. We cast to either — say which water it is going into and we will quote the right one.
What to put on your purchase order
Zinc anodes fail by passivating: they skin over and stop producing current while still looking perfectly serviceable. Iron contamination is the usual cause, which is exactly what ASTM B418 caps at 0.005%. Specify "to ASTM B418 Type I, mill certificate with each lot" and you have something to test against.
Sizing
The specification sets what the anode is, not how much of it you need. That comes from DNV-RP-B401 for ships and offshore structures and ABYC E-2 for boats. Whatever the calculation says, replace at about 50% wasted — output falls away as surface area is lost, so the last half protects far less than the first.
Reading the type code
These designations come from the military specification, not from any manufacturer, which is why the same letters appear across every brand and why an old anode can nearly always be identified. Three letters: metal, then shape, then core. Z is zinc; H hull slab, S submarine slab, T teardrop, E fairwater slab, R rod, B bar, D disc, M mooring chain; then S steel strap, B brass straps, C core strap, P pipe core, M interlocking core, N no core.
