Sling angle calculator that puts the centre of gravity where it is

It puts the centre of gravity where it actually is. The usual method takes the load, divides it by the number of legs and applies a factor for the angle — which assumes the load is shared as the legs are arranged. Move the centre of gravity off centre and it is not. Take 6 tonnes on two legs at 30 degrees with pick centres of 4 m: the uniform method gives 4.29 tonnes a leg, and the geometry gives 4.68 tonnes on the leg nearer the centre of gravity. That is 9% more on the leg that governs, and it is the leg that fails.

Working load limit. WLL is the maximum load the manufacturer certifies the accessory for in a stated configuration, and it is what is marked on the tag and on the certificate. Safe working load is the older term, still in everyday use on site and still written on older gear; where you see SWL on a tag, treat it as the WLL for that item and go to the certificate if there is any doubt. The tool works to the WLL of the actual item you select and shows the utilisation against it, so a set at 85% and a set at 105% are told apart rather than both being called "fine".

Because four legs cannot be relied on to share a rigid load evenly. Small differences in leg length, in lifting point height and in where the centre of gravity actually sits mean two legs can take almost everything while the other two hang on. BS EN 818-4 and BS EN 13414-1 therefore rate a four-leg set on two legs, and that is the figure the tool uses. It then goes further: where you tell it the centre of gravity is off centre, it works the leg tensions by geometry and names the leg that governs, because the two-leg rule is a safe assumption about sharing and not a calculation of what any particular leg is carrying.

Mode factors come from BS EN 818-4 Table 3 for chain, BS EN 13414-1 Tables 3 and 4 with BS EN 13414-2 Annex A for wire rope, BS EN 1492-1 Table 3 for webbing and BS EN 1492-2 Table 2 for round slings. Shackles are to BS EN 13889 and LEEA COPSULE Section 18, beams to BS EN 13155 and the maker’s own span and angle rating. The planning duty behind it is BS 7121-1:2016 clause 4.3.2(l) and LOLER 1998 regulation 8. Every result names the table it came from, so it can be checked rather than believed.

To the vertical, throughout, because that is how BS EN 818-4, BS EN 13414-1 and BS EN 1492-1 tabulate them. It is said on screen and printed on the drawing, because half the arguments about sling angles are two people using the same number to mean different things.

No. It answers the rigging question — what the gear sees, whether it is within its rating and what to order. A lift plan is the whole document: the machine, its duty chart, the ground, the method, the risk assessment and the review. If you need those, the lift planning side of the same application produces them, or I write them as a service.

Slings, shackles, master links and hooks across the EN range — Green Pin, Crosby and Gunnebo among them, and grade 10 chain sets. Modulift MOD beams are read from Modulift’s own tables, and any other beam can be entered by hand from its rating plate. You enter the sling set weight off the tag, because that is the figure on the gear in front of you rather than one from a catalogue.

Yes, and it is the part that saves the most time. FP McCann and Marshalls units come in with their published weights, their lifting points and the maker’s own slinging instructions, so the arrangement starts from what the manufacturer says rather than from a measurement off a drawing. Excavation support is in there too — trench and drag boxes, manhole boxes, shields, slide rail, trench sheets, piles, frames and braces.

No, and it is built so it cannot. The adviser is optional and it does one thing: weigh up the slinging arrangements a rigger would consider and say which suits your job and why. Every number on the screen and on the drawing comes from the standards tables and the geometry. No output from a language model reaches a calculation, ever — that is a rule the application is written around, not a setting.

A PASS or a FAIL with the utilisation and the mode factor used, the sling length to order, and RG-01 — an A3 rigging drawing with the gear drawn as gear rather than as boxes and straight lines: master link, chain legs, safety-lock hooks, shackles and round slings. It prints to PDF under your own branding. Where a check produces a warning rather than a failure, the Appointed Person has to accept it by name before the job is complete.

You start it yourself on this page. Stripe takes your card and charges nothing, you set a password on the spot, and the account opens straight onto the rigging side with everything switched on. It runs for seven days. Stripe emails you before the first payment, and unless you have cancelled it then renews at the monthly subscription price. Cancel at any point in those seven days, from inside the application, and you are charged nothing at all.

So that it starts the moment you decide to, at whatever hour that is, with nobody in the middle. Nothing is charged for seven days; the card is there so that the subscription can carry on by itself if you keep it, and so there is nothing to set up a second time if you do. If you would rather not put a card in before you have seen it, use the form at the foot of this page — the account is then set up by hand, usually the same working day, with no card taken and nothing to cancel.

From inside the application, which opens Stripe’s own billing pages, or by replying to the receipt Stripe sends you. During the trial that ends it with nothing charged at all. Afterwards you keep access to the end of the month you have paid for. Either way your saved work stays on your device — cancelling does not reach into it or delete anything.

No. It works the figures, names their source and draws the arrangement. Whether the lift is safe is a competent person’s judgement and it stays with them — and the gear’s own tag and certificate govern over anything on a screen. Where a figure is not tabulated the application refuses and says so rather than producing something that looks like an answer.