Lift Planning — Drift & Clearance Check
Drift & Clearance Check for engineered lift planning.
Long suspension is a pendulum with your load as the bob: at 20 m of fall, three degrees of swing is a metre of travel at the bottom. Blind picks between structures budget clearance with this arithmetic — and the verdict's two-thirds rule is the difference between a plan and an incident report.
Formula
Note: Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
Drift & Clearance Check for engineered lift planning. A free crane load, wind & rigging safety tool — no sign-up, no upload, instant results in your browser.
About Lift Planning — Drift & Clearance Check
Lift Planning — Drift & Clearance Check computes the governing relationship drift = L·sin(θ_swing) vs clearance (with ⅓ margin) live as you type. Long suspension is a pendulum with your load as the bob: at 20 m of fall, three degrees of swing is a metre of travel at the bottom. Blind picks between structures budget clearance with this arithmetic — and the verdict's two-thirds rule is the difference between a plan and an incident report. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Lift Planning — Drift & Clearance Check
- 1Enter your values — Suspension height (hook above CG), Max expected swing angle, Closest obstruction (sensible defaults are pre-filled).
- 2Read the live results: Horizontal drift at load.
- 3Check the "with your numbers" line to see drift = L·sin(θ_swing) vs clearance (with ⅓ margin) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Lift Planning — Drift & Clearance Check?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula drift = L·sin(θ_swing) vs clearance (with ⅓ margin) with authoritative sources cited on the page (ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices; OSHA 29 CFR 1926 Subpart CC — Cranes & derricks in construction; DNV-ST-N001 — Marine operations (DAF methodology))
- ✓Long suspension is a pendulum with your load as the bob: at 20 m of fall, three degrees of swing is a metre of travel at the bottom.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the lift planning — drift & clearance check use?+
It evaluates drift = L·sin(θ_swing) vs clearance (with ⅓ margin), exactly as published. Sources: ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices; OSHA 29 CFR 1926 Subpart CC — Cranes & derricks in construction; DNV-ST-N001 — Marine operations (DAF methodology). The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Long suspension is a pendulum with your load as the bob: at 20 m of fall, three degrees of swing is a metre of travel at the bottom. Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
When is this calculator the right tool for the job?+
Drift & Clearance Check for engineered lift planning. A free crane load, wind & rigging safety tool. Blind picks between structures budget clearance with this arithmetic — and the verdict's two-thirds rule is the difference between a plan and an incident report. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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