Source: https://guthlabs.ai/docs/instruments/crane-hook-lifting-sling-angle-load-calculator/implementation/

instrument implementation / implementation-contract

# Crane Hook / Lifting Sling Angle Load Calculator implementation

A source-bound implementation contract for Crane Hook / Lifting Sling Angle Load Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t6-136

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification exposes hazards at the zero-angle denominator, requires rejection of negative or out-of-domain angles rather than trusting raw arithmetic, and has a substantial result ambiguity if the angle reference is not enforced as measured from horizontal.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "total_weight_W": 12000,
    "weight_unit": "N",
    "number_of_legs_n": 2,
    "sling_angle_theta": 30,
    "angle_unit": "degrees",
    "angle_reference": "horizontal",
    "leg_spread_geometry": "symmetric; equal angles; centered vertical load"
  },
  "expected_outputs": {
    "tension_per_leg": 12000,
    "tension_unit": "N",
    "required_sling_rating": "not determinable from this formula alone"
  },
  "working": "sin(30°)=0.5. n·sin(theta)=2·0.5=1. T=W/(n·sin(theta))=12000/1=12000 N per leg."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/crane-hook-lifting-sling-angle-load-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/crane-hook-lifting-sling-angle-load-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/crane-hook-lifting-sling-angle-load-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche6/tranche6-results.json`