A cable-laid grommet is an endless lifting sling made from one continuous length of wire rope, laid six times around itself over a seventh length that serves as its core, with the two ends hand-tucked into the body. A cable-laid sling is the same body with a hand-spliced eye at each end. Both exist for lifts a single rope can no longer carry.
We splice both by hand at Darukhana. Every figure below names its document and edition; where we could not source one, there is none.
Four products, four definitions
Vocabulary is the first trap, and it costs money on purchase orders. ASME B30.9 has the cleanest definitions of the four.
| Product | Endless? | The join | What is laid up six-over-one |
|---|---|---|---|
| Cable-laid grommet | Yes | Hand-tucked | One continuous rope, over a rope core |
| Strand-laid grommet | Yes | Hand-tucked | One continuous strand, over a strand core |
| Endless sling (wire rope) | Yes | One or more metallic fittings | Cable-laid or strand-laid rope |
| Cable-laid sling | No | A termination each end, usually a spliced eye | Cable-laid rope |
A grommet has no fitting in it to fail, because its join is tucked. A strand-laid grommet is one level below a cable-laid one, and it is the version the Indian sling standard defines. Cable-laid also names two products: this offshore rope-of-ropes, typically 100 mm and over, and a smaller machine-made body sold into general rigging.
How the body is built
Seven finished wire ropes go into a cable-laid rope: six outers over one core. Each is a unit rope. The core is deliberately the larger — the 2005 edition of IMCA M 179 puts it at 12% to 25% larger — which stops the outers bedding into the middle of the rope under load. That edition also wants six- or eight-strand unit ropes with steel cores, and bars compacted or deformed ones.
Why not one large rope? Strength scales with steel area, but a single rope of that area is far stiffer in bending. Seven ropes laid together buy the area while each keeps roughly the stiffness it had alone. The price is abrasion: many more, much finer outer wires. See rope construction.
Making one by hand
Forming the ring
IS 5245 (Part 1), Appendix H, gives the method for a strand grommet; a cable-laid one is the same shape at a larger scale. You begin with a temporary core — a ring of rod the same diameter as the material laid up — and turn the working length round it, taking the torsion out after every single turn, until it has gone round six times and back to the start. The material needed is about seven and a half times the finished perimeter.
Then the trick that names the product. The rod is cut and drawn out from one side, its place taken by the starting end; the other half comes out the same way, replaced by the finishing end, cut to leave a gap of about 6 mm. Nothing is joined in the load path: the join is a butt, and it sits in the core — the one member the strength calculation does not count.
The tuck
The tools are unglamorous, and IS 5245 (Part 1) lists them: steel block, core knife, cutting pliers, marline spike, flat spike, spoon spike, nipper, hammer and dagger. Three things set how the splice is made.
| Document and edition | Tuck rule |
|---|---|
| IMCA M 179, 2005, Method A | Cross tuck splice, at least five tucks, three with the complete outer unit ropes, against the lay |
| IMCA M 179, 2005, Method B | At least six tucks — five with the complete outer unit rope with the lay, one against it |
| IS 2762:2009, spliced eye, 6–60 mm | Five tucks — three with the full strand, two with half the inner-layer wires removed, against the lay |
Direction: tucks against the lay lock, tucks with the lay do not — which is why the with-the-lay method needs a sixth tuck and still finishes against the lay. Taper: full members first, then reduced ones, so the splice fades into the body rather than stepping out of it. Tails: not trimmed flush, but left at three times the rope diameter and seized down. M 179 puts the method on the consolidation certificate, which keeps the tuck count checkable for the life of the sling.
These eyes are not Liverpool splices. IS 5245 (Part 1) defines Liverpool splicing as laying the tucks around the lay, and warns it shall never be used in a rope free to spin, because the tucks are not firmly held and may draw out. The offshore documents specify a cross tuck, against the lay.
Nor is the tuck put wherever it lands. In the 2005 IMCA text it sits at about a quarter of the length, core butt diametrically opposite, so the join is furthest from the bearing points when the grommet is doubled. Both are marked in red paint, and the rule is absolute: never bend it there. That matters more than on a sling, whose eye carries half the load in its main part — a grommet’s eye carries the same load.
The core: laid in, never cut out
IMCA M 179 says the core is worked in with the splice and not cut out. IS 5245 (Part 1) says the heart strand shall not be removed when the strands are opened for tucking, and requires it rowed in through the first three tucks both ways, so a double heart runs that length.
Then the arithmetic. Count the cross-section and you find fourteen ropes; the 2005 IMCA calculation credits twelve, because the core’s joint is butted, not spliced. It is present, uncredited, and worked in by hand anyway. That read as conservatism until recently: IMCA rewrote the code in April 2025 after destructive testing found spliced cable-laid slings failing in the core first, below the loads the older guidance anticipated.
How a rated capacity is arrived at
We publish no diameter-against-capacity table; the method matters more. In IMCA M 179 it runs: take the minimum breaking loads of the individual unit ropes; apply a coefficient for the spinning loss in cabling them; for a sling, apply a termination efficiency for the hand splice — one figure the code fixes for every maker, which is why splice quality shows up as conformance and never as a bigger number; apply a bending factor wherever the body is doubled over a pin or hook; divide by a design factor. For a grommet the count is twelve unit ropes, and there is no hand-splice term at all.
At 100 mm and over the finished item is generally too large for existing equipment to break — which is why the scheme exists: samples of the unit ropes are broken instead, and the assembly calculated from them under controlled manufacture. Expect three certificates, and read them: consolidation test, dimensional conformity, and examination — the last valid under the 2005 text for six months.
The documents that govern them
HSE published a guidance note in its Plant and Machinery series, PM 20, on cable-laid slings and grommets in very heavy lifting, and no longer issues that class of guidance. With HSE’s approval, IMCA reproduced an updated version as M 179 in August 2005. The current document is IMCA LR008 / M 179 Revision 2, April 2025 — not free, and not a reprint: it adds guidance on handling large-diameter items and on eye opening angle, and changes the rating formulae. Older figures have moved.
The European standard is BS EN 13414-3:2003+A1:2008, Grommets and cable-laid slings. Everyone cites it; almost nobody says what it covers. As quoted in IMCA M 179, its scope covers ferrule-secured cable-laid slings up to 60 mm, and its Annex ZA exclusions include seagoing vessels and mobile offshore units. The hand-spliced heavy-lift product falls outside on both counts.
Where Indian practice sits
India has a sling standard and it has a grommet, but not this one. IS 2762:2009 covers wire rope slings from 6 mm to 60 mm in three types, one of them a grommet — but explicitly a strand grommet: one continuous strand forming six strands around a strand core. It delegates fabrication to IS 5245 (Part 1) and requires each sling leg to be proof tested to twice its SWL — note the term, where an IMCA certificate says WLL.
We searched the published BIS MED 10 list and found no Indian Standard for cable-laid rope, cable-laid slings or cable-laid grommets. The neighbours — IS 2266, IS 5245, IS 12735, IS 3973 — do not address this product. That is what was searched and found, not a claim about the whole of BIS.
So a large cable-laid grommet supplied in India is not certifiable to an Indian Standard. It is built to IMCA M 179, or to EN 13414-3 where size and application fall inside that scope. Name the document on the enquiry, and check the certificate names it back. Our IS standards guide maps the rest of the shelf.
Sealinkers has been at Darukhana since 1977 and runs an in-house test house with a proof-load bed from 1 to 1,200 tonnes, supplying against IRS, ABS, LRS and BV requirements. That bed proof loads components and assemblies and issues the certificate. What it does not do is break a finished large cable-laid sling — nothing that size is broken in a proof-load bed, which is why the unit ropes are broken instead. See our test house.
Handling: a kink is harmless until it is pulled tight
Pull one end of a coil out horizontally along the floor without a rotating table and turn goes into the rope; two kinks form. At that moment they can still be lifted out with no damage at all. Pull on instead and the kinks tighten, the outer strands separate, and the core is forced out between them. What is left is severe localised stress and members out of position. Kinking, crushing, core collapse and knotting are discard conditions — not referral, discard.
The same principle explains a mark people ignore: a cable-laid sling carries a longitudinal alignment line, so it goes back on the hook in the plane it was measured in. Turn changes length, and in a matched pair a drifted length is a load-sharing problem.
Inspection, discard and the record of lifts
Under the 2005 IMCA text a sling or grommet is inspected by a competent person before every use, and thoroughly examined by a competent person independent of the owner at least every six months in use, and either side of long-term storage. Of the nine items examined, three are peculiar to this product: the paint markings, the splice tails and the number of tucks.
Measuring the sling’s length and its splice tails reveals deterioration before anything looks obviously wrong: a splice quietly drawing out shortens its tails and lengthens the assembly. Counting tucks tells you whether the splice you have is the one certified. Broken-wire criteria differ between IMCA, ASME B30.9 and IS 2762 — different counts over different gauge lengths — so use the document your certificate names. Our discard criteria and inspection checklist cover the wider shelf.
One requirement is rarely mentioned outside the code: for each sling or grommet a detailed record of lifts should be kept — date, calculated load, position and angle — held with the certificates and produced on demand to the competent person and the authorities.
What to send us when you ask for a quote
SPECIFYING A CABLE-LAID GROMMET OR SLING
- Which document governs it — IMCA M 179 (state the revision) or EN 13414-3, whether a class society is involved, and which certificates you need.
- Grommet or sling — endless with a tucked butt, or a body with a spliced eye each end.
- The rig, not just a tonnage — legs, angles, whether the body is doubled. See sling angle effects.
- Bearing diameters at both ends, and the radius of anything the body touches.
- Length, how it is measured, and whether you need a matched pair.
- Termination — spliced eye, seized eye or thimble, and whether a mechanical joint is acceptable.
Frequently asked questions
What is the difference between a cable-laid grommet and an endless sling?
Both are endless; the difference is the join. A grommet’s ends are hand-tucked back into the body, so there is no fitting in it. An endless sling’s ends are joined by metallic fittings.
Is there an Indian Standard for cable-laid grommets?
None was found in the published BIS MED 10 list. IS 2762:2009 stops at 60 mm rope and its grommet is strand-laid, so a large cable-laid grommet supplied in India is built to IMCA M 179, or to EN 13414-3 where it fits that scope.
Why is the core not counted in a grommet’s strength?
Its join is a butt, not a splice, so the 2005 IMCA calculation credits twelve unit ropes of the fourteen present. It is still worked in and never cut out — and the testing behind the April 2025 revision found the core failing first in spliced cable-laid slings.
How do I tell a well-made splice from a poor one six months later?
Measure and count rather than look. Compare the length and the splice tails against the dimensional conformity certificate, and count the tucks against the method the consolidation certificate names. Then look for broken wires near the splice, crushing or abrasion on it, and distortion at the eye throat, where an oversized pin does its damage.
Talk to the people who splice them
These are made to order, and the specification is most of the work. Send us the duty, the rig geometry, the bearing diameters and the document you certify to. We hand-splice this work in-house at Darukhana alongside wire rope slings, for offshore, shipping and port work. Request a quotation or talk to our engineering desk.
