A ship anchor is not made by one process. IACS UR A1 requires anchors to be manufactured to UR W29 and anchor chain cables to UR W18, and keeps the two documents separate [1]. UR W29 covers anchors of cast steel, forged steel, or fabricated from welded castings, forgings and rolled plate, and lists fluke, shank, stock, pin, bars and anchor shackle as its main components [2]. The revision reviewed here is Rev.1, October 2026, which applies to anchors manufactured on or after 1 January 2028 [2].
The three routes sit side by side in one rule. What the rule does not do is choose one for the anchor as a whole: the material requirement is assigned part by part. So a buyer who sees a cast fluke, concludes the anchor is a casting, and asks for drop-test records against a forged shank is asking for evidence the rule never required. The route belongs to the part.
Three routes, assigned by component
UR W29 Table 1 sets starting materials component by component [2]. Its shape is the argument: one anchor can carry a cast fluke, a fabricated shank and a forged shackle, each read against its own line.
| Component | Permitted requirement, UR W29 Table 1 | What it settles |
|---|---|---|
| Fluke | W8 cast, W11 fabricated or W7 forged | Three routes; none carries over to the shank. |
| Shank | W8 cast or W11 fabricated | A fabricated shank does not make the fluke fabricated. |
| Anchor shackle | W7 | Stated for the shackle, not inferred from the shank. |
| Swivel | W8, W18 or W7 | Its own line, its own options. |
| Stock | W8 cast, W11 fabricated or W7 forged | Its own line, not the fluke's. |
| Pin, bars | W11 or W18; no cast bar for Grades 2 and 3 | Bars restricted to rolled or forged product. |
A mixed anchor is normal, not a deviation. Where a works proposes a cast fluke on a fabricated shank, the specification has to name both routes and the test file has to match the part. A quotation line reading "anchor: cast" describes one part and presents it as the whole.
One exclusion runs one way only: bars of Grades 2 and 3 are accepted rolled or forged, and cast bar is not permitted [2]. That is a sentence about bars. It says nothing against cast flukes or shanks, and it does not rank the routes; the table lists them as alternatives where alternatives exist.
What must exist before the first anchor
Two things precede manufacture [2]. First, a written procedure agreed with the classification society, describing each controlling step: design, starting materials, heat treatment, repair, assembly, fabrication methods, inspection and testing. Second, a works assessment of capability in quality control, traceability and identification, production and test equipment including calibration, and the operations behind the quality of the finished anchor.
That becomes four requests a buyer can make before a purchase order:
- the procedure, and the society's agreement to it;
- the works assessment record, and the component forms it covered;
- the traceability scheme for flukes and shanks;
- the calibration status of the proof-testing equipment.
Material to another standard carries a further list: the standard and grade, the manufacturing process, the chemical composition, the heat treatment or delivery condition, and the sampling plan for mechanical properties — how, how often, at which stage, at what position and at what size [2]. That doubles as a question sheet. It applies to substitution only.
Welding and heat treatment
The routes diverge here, and the divergence is easy to overstate.
Cast and forged components are heat treated: fully annealed, normalised, or normalised and tempered, to UR W7 and UR W8 respectively [2]. Fabricated and weld-repaired components may need stress relief after welding depending on weld thickness; where required, it follows the accepted and approved welding procedures, and its temperature is not to exceed the tempering temperature of the qualified WPS [2].
Welding is a qualification, not a technique: all welding on fabricated anchors and components, including pin securing and weld repair, is by qualified welders to procedures qualified under UR W28, UR W32 or a recognised standard, with consumables approved under UR W17 [2].
So the document to ask for differs. A welded assembly has a qualified procedure and, where required, a stress-relief step tied to it; a cast or forged part has a heat-treatment record. Asking a foundry for a WPS, or a fabricator for a normalising record, is a sign the route has been misread.
The test sequence
Five steps. Only the first two depend on the part being cast.
- Drop test. Each cast fluke and cast shank is raised to 4 m and dropped onto a solid steel foundation, then examined visually for cracks; if fracture is found, repair is not permitted and the part is rejected [2]. Forged and fabricated parts are not given this test.
- Hammering. Cast components are hammered with a 3–7 kg hammer under the same programme [2].
- Proof load. Every ordinary, HHP and SHHP anchor is proof loaded at a facility recognised by the society, with the equipment calibrated annually [2]. This step is not conditional on route.
- Examination and NDT. The anchor is examined for cracks after proof loading, and NDT follows the proof load test [2]. Methods and locations depend on the part's form, so it does not collapse into one test for the whole anchor.
- Mass and dimensions. Checked by the manufacturer with the surveyor monitoring [2]: a manufacturing check, not a performance test.
The two product-test programmes make the conditionality explicit. One applies to cast components and not to forged or fabricated ones; the other applies to all three forms, with Charpy impact testing required for cast components under it [2]. The asymmetry is the rule's, not a works' preference, and it is why a cast anchor arrives with test records a fabricated one does not have.
UR A1 adds the mechanics: the load is applied on the arm or palm, both arms of a stockless anchor are tested in turn, and a multi-piece anchor is checked after the test for free rotation of the head over the full angle [1].
Proof load is not a holding-power test
Two loads answer two questions, and are routinely compared as one.
The proof load is a per-unit acceptance test, applied to every anchor before delivery: it establishes that this casting, forging or weld carried the required load without cracking. The value is read from mass — an ordinary anchor to the load for its actual mass, an HHP anchor to the load for 1.33 times its mass, an SHHP anchor to the load for twice its mass [1].
The holding-power test at sea is a design-approval test, run on representative sizes and several bottom types, establishing whether the design develops its claimed holding force in the seabed. It is required for HHP and SHHP approval, and its test load is not to exceed the anchor's proof load [1].
So a certificate showing a proof load says nothing about holding power, and a sea-test report on a representative size says nothing about the anchor in the crate. The numbers do not line up because the questions differ.
SHHP adds inspection: full surface examination by PT or MT after proof loading, with ultrasonic testing of cast steel where feeder heads, risers or weld repairs have been removed [1].
Marking, certificate and paint
Marking goes on the shank and the fluke, with at least the mass (and HHP or SHHP letters where they apply), the society's stamp, the manufacturer's mark and an identification such as a test or certificate number [2]. Cast shanks and flukes carry one more: a unique cast identification cast into the part [2]. That number gives the part its own identity in the test and certificate records.
The certificate, issued by the society, states at least manufacturer, type, mass, proof loads, drop and hammering results or the alternative programme and its report reference, NDT results, fluke and shank identification numbers, material grade, heat treatment and the marking applied; starting-material certificates must meet the applicable UR requirements [2]. Those fields are the manufacturing file on one page — what the part is, what was done to it, what was tested, and which number ties paper to steel.
Painting comes last. Anchors are not painted until all tests and inspections are complete [2].
What a buyer can ask for at each stage
Each request corresponds to a step the rule requires. The third column is what a supplier questionnaire usually leaves out.
| Stage | Evidence that exists | What it does not prove |
|---|---|---|
| Works | Assessment of quality control, traceability, equipment, calibration [2] | That this anchor was made to the agreed procedure. |
| Material | Certificate to the applicable UR for the grade [2] | Finished-part properties after forming and heat treatment. |
| Welding | Qualified welders, approved WPS, approved consumables [2] | The welds actually made on this anchor. |
| Heat treatment | Record to UR W7 or W8, or stress relief to procedure [2] | The mechanical result on its own. |
| Cast tests | 4 m drop, 3–7 kg hammering, visual examination [2] | Anything about forged or fabricated parts. |
| Proof load | Per-unit record, recognised facility, calibrated equipment [2] | Holding power. |
| NDT | Results after proof loading, at the required locations [2] | The whole volume of the component. |
| Dimensions | Manufacturer's check, surveyor monitoring [2] | Performance; it is a dimensional record. |
| Marking, certificate | Two-place stamping, cast-in identification, society certificate [2] | Service performance; it records what was tested. |
A complete file is evidence that the specified tests were carried out and recorded. It is not a ranking of suppliers, and not a prediction of how an anchor will behave on a given seabed.
What this does not establish
This is a manufacturing and testing baseline, and three questions sit outside it. Holding power for HHP and SHHP is established by a sea test on representative sizes and bottom types, not by a test of the delivered anchor or a prediction for a particular berth [1]. Suitability for a vessel is settled by the equipment selection and the project's class rules. And the applicable text is the one in force at the date of manufacture: confirm which revision of UR W29 the contract names, because the revision reviewed here applies to anchors manufactured on or after 1 January 2028 [2].
Design and manufacturing documents answer different questions, and are worth keeping apart as the routes are. The Hall anchor page describes the parts of one named design; read it for part names, not for a manufacturing route. The AC-14 anchor page separates the design, its approval and the anchor as delivered.
For an enquiry, four documents carry most of the answer: the drawing, the route proposed for each component, the test programme that follows from those routes, and the class contract date. Send them with the enquiry so specification and rule can be read together.
References
[1] International Association of Classification Societies, UR A1 — Anchoring Equipment (Rev.7 2020, Corr.1 2021), A1.1.6 (manufacture), A1.4.2 (holding-power test at sea), A1.4.4.1–A1.4.4.3 (proof load, HHP and SHHP) (https://ww2.eagle.org/content/dam/eagle/regulatory-news/2022/IACS-UR-A1.pdf). Cited for the reference of anchor manufacture to UR W29, the application point and arm sequence of the proof load, the HHP and SHHP mass multipliers and the scope of the sea holding-power test. No load value is reproduced.
[2] International Association of Classification Societies, UR W29 — Requirements for manufacture of anchors (Rev.1, October 2026), §1.1, §2.3, §3 a) and b), §3.2.2, §3.3, §4.1.2, §4.1.4, §4.1.6, §4.3, §4.5, §4.6, §4.7, Table 1 (starting materials, notes 1 and 8) and the product-test programme table (https://www.classnk.or.jp/hp/pdf/info_service/iacs_ur_and_ui/ur_w29_rev.1_oct_2026_ul.pdf). Cited for the three permitted product forms, the component-by-component material table, the procedures and works assessment, welding and heat treatment, the drop and hammering tests, the proof load and NDT sequence, marking, certification and the paint sequence. The revision reviewed applies to anchors manufactured on or after 1 January 2028; earlier revisions were not read for this article.
