DNV GL type approval is what separates offshore lifting gear from general industrial equipment. Offshore and marine lifting operates under a different regime: loads are lifted from moving vessels, in cold conditions, where a dropped object has consequences a factory floor does not. Type approval means the component has been assessed and certified by DNV GL against that regime, not merely manufactured to an EN standard.
The material specification reflects it. These links are made from special alloy steels selected for good ductility at low temperature — a minimum of 42 J at -40 °C. Ductility is what stops a component failing brittly under shock load in the cold, which is precisely the offshore failure mode.
Grade 8 DNV Master Link is a single master link.
Key Features
- DNV GL type approved: Assessed and certified for offshore and marine lifting, not merely EN compliant
- 42 J minimum ductility at -40 °C: What stops a component failing brittly under shock load in the cold
- Special alloy steel: Selected for low temperature performance rather than capacity alone
- Purple painted finish: Identifies the range — never repaint a lifting fitting
- For 1 and 2 leg slings: Sized by chain diameter and leg count
- Fully certificated: With traceability to the manufacturing batch
Technical Specifications
| Product Code |
W.L.L. (t) |
M.P.F. (kN) |
M.B.F. (kN) |
D (mm) |
L (mm) |
W (mm) |
Weight (kgs) |
| F22 |
6.7 |
164 |
329 |
23 |
270 |
140 |
2.5 |
| F25 |
8.9 |
218 |
437 |
25 |
270 |
140 |
3 |
| F28 |
14.5 |
356 |
711 |
27 |
270 |
140 |
3.5 |
| F32 |
24.15 |
592 |
1,185 |
33 |
270 |
140 |
5.4 |
| F36 |
28.91 |
709 |
1,418 |
36 |
270 |
140 |
6.5 |
| F40 |
34.29 |
841 |
1,682 |
40 |
275 |
150 |
8.3 |
| F45 |
38.3 |
939 |
1,878 |
45 |
340 |
180 |
12.8 |
| F50 |
50.56 |
1,240 |
2,480 |
50 |
350 |
190 |
16.5 |
| F60 |
67 |
1,643 |
3,286 |
60 |
430 |
230 |
29.1 |
| F70 |
85 |
2,085 |
4,169 |
70 |
480 |
260 |
44.6 |
Working Load Limits and full dimensional data are in the information sheet. DNV GL type approval certification is available on request.
DNV GL Type Approved | Grade 8 | 42 J at -40 °C | Offshore and Marine Lifting
Grade 8 alloy steel, DNV GL type approved for offshore and marine lifting. Manufactured from special alloy steels having good ductility at low temperature, with a minimum of 42 J at -40 °C. Marked with material grade, manufacturer’s identification, size and traceability code, and supplied with a certificate. Under LOLER 1998, thorough examination by a competent person at intervals not exceeding 12 months; offshore operations may impose shorter intervals.
Suitable Applications
Specified for offshore and marine lifting: platform and vessel work, subsea deployment, wind farm installation and maintenance, and any lifting operation working to DNV GL requirements. Also used onshore where low temperature ductility matters — cold store, winter outdoor work in northern climates, and cryogenic plant surroundings. Where the work is general industrial and onshore, a standard Grade 8 master link is considerably cheaper.
More About This Product
Shackles are the most-handled component in any lifting operation, and that is precisely why they wear out first. A sling gets rigged and derigged; a shackle gets rigged, derigged, dropped, driven over, thrown into a box and picked up by whoever needs one. Most lifting gear fails from a single overload; shackles fail from accumulated inattention.
The grade markings matter more than most people realise. A Grade 6 high tensile shackle to BS EN 13889 and a Grade 8 alloy shackle look similar and share the same body shape, but the alloy version carries considerably more at the same size. Once a shackle is in a box with fifty others, the only way to tell them apart is the marking — which is why an unmarked shackle has to be scrapped no matter how good it looks.
Understanding the Load Path
A shackle has two distinct load-bearing elements and they do different jobs. The bow takes the sling; the pin takes the load. Reverse that — put the sling on the pin and the load on the bow — and two things happen. The sling bears on a smaller radius than it was designed for, and any movement in the sling starts to rotate the pin.
On a screw collar pin that rotation is the failure mechanism. A sling shifting under a settling load, or vibration transmitted from plant nearby, will slowly unscrew the pin over minutes or hours. It rarely happens quickly enough for anyone to see it happening.
The second consideration is angle. A shackle loaded in line with the pin carries its full rating. Loaded at an angle across the bow it carries substantially less, and published derating tables cover a limited range of angles — beyond that range no figure is published because none applies. On a multi-leg sling every leg is at an angle by definition, which is why the bow shackle exists and why putting a multi-leg sling into a dee shackle is a genuine mistake rather than a preference.
How to Use
- Confirm type approval is required: If the operation works to DNV GL, standard EN-marked gear may not be acceptable.
- Size for the chain AND the leg count: Both matter on a master link.
- Check it fits the crane hook: Freely, without being forced or able to tip.
- Watch the included angle: As the included angle widens, the tension in each leg rises sharply and can approach or exceed the weight of the whole load.
- Keep the assembly one grade: And ideally one approval regime throughout.
- Do not modify: Never weld, heat, machine, drill or repaint.
Warning: The master link carries the entire load. On offshore work, confirm the whole assembly meets the approval regime — a type approved link in an otherwise unapproved sling does not make the sling approved.
Safety Information
- Never exceed the marked Working Load Limit for the number of legs and included angle.
- Confirm the whole assembly meets the required approval regime.
- The master link must fit the crane hook freely without being forced.
- Derate for included angle on multi-leg slings.
- Withdraw any link showing wear beyond the manufacturer’s stated limit, elongation, distortion or cracks.
- Never weld, heat treat, machine or repaint.
- Offshore operations may impose inspection intervals shorter than the 12 months required under LOLER 1998.
Inspection and Maintenance
Measure section diameter at the crown and at every bearing point against original dimensions and withdraw at the manufacturer’s stated wear limit — the crown wears against the crane hook and is usually the worst point. Check for elongation by measuring internal length, since a stretched link is direct evidence of overload and grounds for immediate withdrawal. Look for nicks, gouges and cracking at the points of maximum curvature, and confirm the marking and traceability code remain legible. On offshore assemblies, inspection intervals are often shorter than the 12 months LOLER requires, and the operating regime will specify them.
Downloads
Frequently Asked Questions
Q: What does DNV GL type approval actually mean?
That the component has been assessed and certified by DNV GL against the offshore and marine lifting regime, rather than simply manufactured to an EN standard. Offshore operations frequently require it, and EN-marked gear may not be acceptable.
Q: What does 42 J at -40 °C mean?
It is an impact toughness figure — the energy the material absorbs before fracturing, measured at -40 °C. High ductility at low temperature is what stops a component failing brittly under shock load in the cold, which is the offshore failure mode that matters.
Q: Can I use it for general onshore lifting?
Yes, and it will perform well, but you are paying for approval and low temperature ductility you may not need. A standard Grade 8 master link is considerably cheaper for general industrial work.
Q: Does one approved link make my sling approved?
No. The approval regime applies to the assembly. A type approved link in an otherwise unapproved sling does not make the sling acceptable offshore.
