1Sling Load Calculator

Tension per leg: T = (W × HitchFactor) / (N × sin θ) — where θ is the angle from horizontal. Compare against the sling Working Load Limit (WLL) to confirm safety.

Total load weight i

Number of sling legs Per ASME B30.9: 3 & 4-leg bridles are conservatively designed assuming only 2 legs carry the full load.

Sling angle from horizontal (°) i

15°60°90°

Hitch type i

Sling Working Load Limit (WLL) per leg, optional i

Result

— per leg

—

Vertical share / leg—

Load Angle Factor (LAF)—

Hitch factor—

Total load (kg)—

vs WLL—

2Centre of Gravity Estimator

Add components (pipes, plates, vessels, motors) and the tool computes the combined CoG via mass-weighted averages: X̄ = Σ(mᵢ·xᵢ) / Σmᵢ. Use this to position lift points and prevent tipping during multi-point lifts.

Item	Mass (kg)	X (m)	Y (m)	Z (m)

Combined Centre of Gravity

Total mass— kg

CoG X— m

CoG Y— m

CoG Z— m

18Crane Load Chart Estimator

Estimate working load by operating radius and boom angle, applying the standard derating factors (configuration, on-rubber/outriggers, side-stability). Always cross-check against the actual manufacturer load chart for your crane and configuration.

Crane size class i

Boom length (m)

10 m30 m80 m

Operating radius (m) i

3 m10 m60 m

Setup

Outriggers fully extended Outriggers partial On rubber / pick-and-carry

Quadrant

Over rear Over side Over front

Planned load (kg) i

Allowable load & utilisation

— kg permitted

—

Boom angle—

Configuration factor—

Geometry factor (radius)—

Utilisation—

Tipping check (R/L)—

—

26Sling Mode Factor (LEEA)

Formal LEEA Mode Factor lookup. Effective WLL = WLL_single × Mode Factor. The Mode Factor (M) accounts for how the sling carries the load (single, choke, basket, parallel) and the leg angle. Aligned to LEEA COPSURE 1.6 / EN 13414-1.

Sling type

Chain Wire rope Round / web

Mode i

Angle from vertical β (°) i

0°30°75°

LEEA caps included leg angles at 120° (β = 60°) — beyond this is non-routine.

Single-leg WLL (vertical, kg)

LEEA Mode Factor & effective WLL

— kg effective WLL

—

Mode Factor M—

Angle factor—

Per-leg tension @ rated load—

Reference—

—

27Lift Plan Categorisation (Routine / Non-routine / Critical)

Score-based classifier aligned to LEEA Lift Planning guidance and IOGP 376. Returns the lift category (1 / 2 / 3) with the documentation and sign-off level required.

Load weight (t)

Crane chart capacity at planned config (t)

Lift mode

Personnel exposure

Visibility

Environment

Load value / criticality

Lift category

—

Capacity utilisation—

Risk score (0–20)—

Documentation required—

Approval level—

Pre-lift requirements—

—

28D/d Ratio Calculator

Compares bend radius (D) of a sheave, drum or fitting to rope diameter (d). When D/d falls below LEEA-recommended ratios, rope efficiency drops and the WLL must be derated. References LEEA COPSURE 1.4 / 4.6 and ISO 4308.

Application

D — drum / sheave / pin / edge diameter (mm)

d — wire-rope / chain / sling diameter (mm)

Single-leg WLL (kg, optional)

Bending efficiency & derated WLL

— D/d ratio

—

Bending efficiency η—

Derated WLL—

Recommended minimum D/d—