An anchor cable does not have one connection in it. It has three, and they are not the same kind of joint. At the anchor end, the cable meets the anchor through a part that may belong to the anchor's own approved design. Between shots, two lengths of chain meet through a joining shackle, and the parts either side of that shackle depend on which type of joint it is. At the far end, the cable is terminated. Each position asks a different question of the buyer, and each is answered by a different document.
What decides the part is not the catalogue category. It is four things read together: the joint form shown on the drawing, the grade and nominal size the part is proof loaded against, the identification marks the part carries, and the scope of the certificate that covers it. A shared nominal diameter is one field on that list. It is not a fit.
The individual parts — common, enlarged and end link, joining shackle, end shackle, swivel — are already defined in our chain overview [1], and this article does not repeat that list. It reads the cable by position instead: what each position has to do, which parts appear there, and what has to be on paper before an order makes sense.
Three positions, three different jobs
Start at the anchor and work inboard. The order of the parts is fixed by the arrangement; the identity of each part is not.
At the anchor end, the last length of chain before the anchor is an outboard chain-shot, defined as a short shot containing a common link, an enlarged link, and either an end shackle or a swivel shackle [1]. That "either" is the first decision at this position, and it is not a cosmetic one — the two options can follow different approval routes (see below). The end shackle itself is defined as an enlarged shackle connecting the outboard chain-shot to the anchor [1], which is a statement about its position and its size relative to the chain, not about its part number.
At a shot-to-shot joint, a joining shackle connects one chain-shot to the next, and the standard recognises D-type and Kenter type joining shackles [1]. The joint is where two shots of the same nominal size meet, which is exactly why it is the place where "same size" gets read as "same part". The links immediately either side of the shackle are not automatically common links; that depends on the joint form.
At the far end, the cable is terminated. ISO 1704 gives connecting the outboard chain-shot to a chain end shot as one of its worked examples [1]. One sentence is enough here: the termination is a position on the drawing, and it should be shown as one rather than left to the phrase "complete cable".
A working habit follows from this. Read the drawing position by position, and for each position write down three things: the joint form, the part named at that position, and the document that approves it. If any of the three is missing, the position is not yet specified — whatever the parts list says.
Two shot joints, two different transitions
Both joint types join shots. They do not take the same parts around them, and the difference is visible in how the standard defines its links.
A D-type joint is a shackle body closed by a pin through two eyes. In the arrangement ISO 1704 describes, the links either side are a pair of strengthened links: an enlarged link connecting a common link to an end link, and an end link attached to the shot end [1]. The standard defines both links by reference to that arrangement — the enlarged link as the strengthened link connecting a common link and an end link where shots are joined with a D-type joining shackle (or connecting a common link and a swivel), and the end link as the strengthened link attached to the ends of two shots in the same case, or connecting an outboard chain-shot with an end shackle [1]. In other words, the pair exists to make the transition between a common link and the joining shackle; it is a transition component, not a chain link that happens to be fitted at a joint.
A Kenter joint is a different object. It is built from two interlocking halves with a coupling piece between them, held by a pin driven diagonally through the assembled unit and secured against working out [4]. There is no bow closed by a single pin across two eyes. That is why the two joint types carry different dimension sets on paper, and why a Kenter shackle cannot be checked against a D-type drawing.
The practical consequence is narrower than it first looks, and worth stating precisely. Do not carry the enlarged-link-plus-end-link pair across to a Kenter joint because "every joint has transition links". ISO 1704 attaches that pair to the D-type arrangement in its definitions [1], and it presents its connection arrangements — shots joined by a joining shackle, the outboard shot to the anchor, the outboard shot to a chain end shot — as examples rather than as the only permitted arrangement [1]. So the correct conclusion is not "one joint type needs transition links and the other does not"; it is that the parts at any given joint must be read off the drawing that covers that joint, and a parts list copied from another vessel's arrangement is not that drawing.
There is a second reason to keep the two joint types apart on paper. The form and proportion of links and shackles have to follow a standard recognised by the classification society — ISO 1704 is the one LR names — or a specifically approved design [2]. A Kenter shackle is recognised in that figure series as a shape of its own, listed as the lugless shackle of the Kenter type [2]. Two joint types, two recognised shapes, and therefore two different sets of dimensions to check rather than one drawing with a substitution note.
Where the anchor-end swivel sits
The swivel is the part most easily filed in the wrong drawer, because it looks like chain hardware and can be treated as one.
Its defined function is narrow: a swivel is the movable component of the outboard chain-shot that prevents excessive twisting of the chain cable, and a swivel shackle is a shackle fastened to the anchor shackle or the anchor shank with the same function [1]. The standard keeps them as two separate entries, so they should be kept as two separate words on an order. Nothing in that definition is about holding capacity, and this article makes no claim about one.
What matters for procurement is that the same part can sit in two different approval paths depending on where it is fixed. In the LR rules read for this article, a swivel or swivel shackle attached directly to the anchor shank in place of the conventional D shackle is treated under anchors, while swivels in other positions are covered as chain-cable fittings [2]. Where such a shackle is permanently attached to an anchor shank, it is to be tested in combination with the anchor assembly, in accordance with the approved design [2]. Where a swivel shackle is not permanently attached as part of an approved anchor design, it is design approved and tested as a chain-cable fitting [2].
That is a documentary distinction with a commercial edge. The same drawing call-out — "swivel shackle at anchor" — can mean a component inside an approved anchor design, tested with the anchor, or a chain accessory approved and tested on its own. Which one applies is decided by the anchor design and the drawing, not by the supplier's product page. Ask the question before comparing price or delivery, because the two answers do not lead to the same paperwork.
The one table: position, job, and the check that decides the order
| Where it sits | What it does | What to verify before ordering |
|---|---|---|
| Anchor-end shackle (end shackle) | Connects the outboard chain-shot to the anchor, as an enlarged shackle [1] | Whether the approved drawing places it inside the anchor design or treats it as a chain-cable fitting, and that the certificate covers that position |
| Anchor-end swivel or swivel shackle | Prevents excessive twisting of the cable; a swivel shackle fastens to the anchor shackle or shank [1] | Which approval route applies — tested with the anchor assembly where permanently attached, or approved and tested as a chain-cable fitting where not [2] |
| D-type joining shackle, with enlarged and end link | Joins two shots, with a pair of strengthened links making the transition either side [1] | That the drawing names the joint type and the transition links, and that the connection method and pin-hole size are on the approved drawing [3] |
| Kenter joining shackle | Joins two shots through two interlocking halves and a coupling piece held by a pin [4] | The same drawing check, without carrying the D-type transition links over to this joint |
| Chain-end termination | Terminates the cable at the end away from the anchor; the standard's example connects the outboard shot to a chain end shot [1] | That the termination is shown on the approved drawing and falls inside the certificate scope |
Every cell is a check, not a specification. What makes each check possible — a drawing, a mark or a certificate — sits in the right-hand column, which is why the middle column fits in one line and the right-hand one does not.
Names and letters are not identifiers
Four traps recur at this stage of an order, and none of them is solved by a better glossary.
The same part carries different names. One manufacturer's manual dimensions an end shackle and notes in the same heading that it is also called a "D" type anchor shackle [5], while the LR figure series lists Dee shackle, end shackle and lugless shackle as separate items [2]. A buyer reading the first document and a surveyor reading the second are looking at the same anchor-end position under two labels. The only reliable identifier is the position on the drawing.
The same value carries different letters. Published Kenter dimension tables use different letter codes for the same values: one supplier labels a dimension set L1, P4, W4 and K, while another labels the corresponding values A, B, C and E [6]. Neither supplier is wrong; a letter means what the drawing it sits on says it means. Comparing tables across suppliers, letter for letter, produces mismatches that do not exist and hides ones that do.
A list of names is not a required configuration. One classification guideline does give a comparable list of what it covers — common links, enlarged links, end links, Kenter shackles, joining shackles, end shackles, swivels and swivel shackles [3]. That is useful as a vocabulary check when reading a drawing. It is not a statement that every one of those parts belongs on a given vessel, and it is not a configuration to copy.
The same nominal size does not mean the same dimensions. Nominal size is defined as the nominal diameter of the common link, and the dimensions of chain and shackles are measured after the proof loads have been applied [1]. Tolerances are themselves stated on the nominal diameter, so two items sharing a nominal size are not thereby dimensionally identical [2]. Add the earlier point that an oversized or higher-grade fitting is a deviation requiring approval and individual break-load testing rather than a free upgrade [2], and the ordering rule becomes plain: a nominal diameter starts the conversation, it does not close it.
The habit that survives all of these traps: take the drawing first, then the dimension table belonging to that drawing, then the part. Any order that starts from a name, a letter or a diameter is working backwards.
What has to travel with the parts
Chain-cable accessories, including spares, are to be proof loaded to suit the grade and size of the cable they are intended for [2]. Note the pair: grade and size, not size alone. A fitting proved for one grade at a given size is not thereby proved for a higher grade at the same size.
Under the LR rules read here, fittings such as shackles, swivels and swivel shackles are to be forged or cast in steel of at least Grade U2 [2]. That requirement is scoped to those rules and to the edition cited below; it is not offered as every society's minimum, and a project under another society's rules has to be read against that society's text.
Three documents then decide whether the parts can be accepted.
The drawing: CCS requires approval drawings to show the method of connection of chain cables and anchors and the pin-hole size of accessories [3]. That is why the connection drawing counts as a purchasing document and not as a formality — the pin-hole size is the interface that a parts list cannot describe.
The marks: every fitting is required to carry identification marks including the certificate number, the proof load and grade of chain, and the surveyor's stamp, under the rules read here [2]. Those marks are what a goods-receipt check can be made against, and the marks belong on the fitting itself.
The certificate scope: a certificate may cover chain cable only, fittings only, or chain cable with associated fittings [2]. A file that proves the chain and stays silent on the end shackle has not proved the connection. Read the scope, not the product name on the cover.
Next step
To specify a connection rather than a list of parts, four things are needed for each of the three positions: the connection drawing that covers it, the grade and nominal size as ordered, photographs or rubbings of the marks on the parts already in service, and the certificate with its scope visible.
With those in hand, the parts can be identified against your own documents. The connecting parts section of our catalogue is where these shackles and joining parts sit, and the anchor chain range is the parent product line. If the drawing is incomplete, contact us with what you have and the position that is unclear, and the part can be read against the position rather than against a name.
References
[1] ISO 1704:2022(E), Ships and marine technology — Stud-link anchor chains, publisher preview (iTeh), clauses 3.1–3.11 (terms and definitions), 4.2.1 (nominal size and measurement after proof load) and 7.1 (examples of connection arrangements) — https://cdn.standards.iteh.ai/samples/77746/bf35a8e6871a4fcaabbef575f43d1dab/ISO-1704-2022.pdf. Used for the definitions of chain-shot, common, enlarged and end link, joining shackle, end shackle, swivel and swivel shackle, and for the wording that presents connection arrangements as examples. Not used for dimensions: the preview covers clauses 1–7.1 only and omits the Kenter, swivel and swivel-shackle dimension clauses and Figures 10–12.
[2] Lloyd's Register, Rules for the Manufacture, Testing and Certification of Materials (July 2022), Chapter 10 Section 1 clause 1.1.3 (https://imorules.com/LRMAT_CH10_1.html) and Section 2 clauses 2.11.8, 2.13.7, 2.13.8, 2.13.13–2.13.14, 2.13.17, 2.15.1 and 2.16.1–2.16.2 (https://imorules.com/LRMAT_CH10_2.html), read in the imorules mirror (Classification Society 2024, version 9.40). Used for the anchor-end swivel treatment, the combined test with the anchor assembly, proof loading by grade and size, the minimum fitting grade, approval of increased dimensions or higher-grade material, the tolerance basis, marking and certificate scope. Every statement taken from this source is scoped to these LR rules and this edition; none is presented as a requirement of classification societies generally.
[3] China Classification Society, Guideline W-09(202307) — Product inspection of anchor chain cables and accessories — https://www.ccs.org.cn/ccswzen/file/download?fileid=202306130922109885. Used for the list of accessories the guideline covers and for the content required on approval drawings (method of connection of chain cables and anchors, pin-hole size of accessories). A works-approval guideline for products built to CCS Rules, not a SOLAS-level requirement and not evidence of a mandatory parts list.
[4] US20190162270A1, published patent application, description background on the Kenter shackle — https://patents.google.com/patent/US20190162270A1/en. Used only for the structural principle of a Kenter-type joining shackle (two interlocking halves, coupling piece, pin driven through the assembly). A patent background description, not a manufacturer's specification and not a source for dimensions or assembly procedure.
[5] Katradis, User's Manual — Studlink Chains & Accessories, section 2 "Installation of End shackle" — https://www.katradis.com/wp-content/uploads/2024/11/studlink-chains-accessories-useres-manual-.pdf. Used for one example of a part named differently in different documents (an end shackle also called "D" type anchor shackle). One manufacturer's manual; not a rule requirement and not evidence that the differently named parts are interchangeable.
[6] Damen Anchor & Chain Factory, Kenter type joining shackle product sheet — https://medialibrary.damen.com/asset/8a3b2045-f469-4171-856f-a90b32a11b6a/product-sheet-accessories-kenter-type-joining-shackle.pdf — and Posidonia, Kenter Joining Shackle product sheet — https://www.posidonia.com/images/accessories/ACC-Kenter-joining-shackle-posidonia.pdf. Used only for the observation that the two published dimension tables assign different letter codes to the same values. That comparison is this article's own reading of two supplier sheets, not a statement by either supplier, and no dimension value from either sheet is used here.
