Snubline

Educational Force Comparisons

Only for iPhone

Free · In‑App Purchases

iPhone

Explore rigging equations and compare assumed values for education. Provisional model; results must not guide field operations or equipment selection. Explore rigging physics with an educational model. Snubline uses assumed inputs to illustrate equations and compare numerical values. It has no independent professional validation or complete rope calibration dataset. It is not a professional planning or load-safety assessment tool. Do not use its results to select equipment, determine actual loads, plan a cut, or decide whether an operation may proceed. Obtain qualified on-site assessment independently of the app. THE EDUCATIONAL MODEL - Compare snubbed and constant-slip let-run assumptions using a closed-form spring-mass equation. - Inspect peak tension, dynamic load factor, stretch, block force and device force, with equation details. - The rope conversion factor 0.075 and example moduli are provisional teaching values. - The 75%-125% display range is illustrative, not a validated error bound or confidence interval. Actual loads may fall outside it. - Fall factors above 2 are limited to 2, with a visible warning; the result no longer represents the full entered drop. NUMERICAL FORCE-VERSUS-RATING COMPARISONS Enter your own tag ratings and design factors. Within WLL, Approaching WLL, Exceeds WLL and Exceeds MBS describe numerical comparisons of model values only. They do not approve equipment or operations. EXAMPLES AND DOCUMENTS Estimate log weights from idealized geometry and species density, with estimate labels carried into comparisons. Save scenarios, gear records and jobs. Compare scenarios and share educational comparison PDFs or images. Existing frozen snapshots remain stored; documents rendered by this version carry the current educational restriction. TRANSPARENCY The free model page explains equations, provisional calibration, formula-test limitations and omitted effects including swing, tree flex, rope heating, friction variation and fatigue. Climbing, life support and crane operations are outside the model. YOUR DATA Records remain on your device. No account or cloud sync. If saved records cannot be opened, recording is paused and existing database and attachment files are kept. FREE Both model modes, equation details, the weight estimator, the model page, three Gear Locker items and one job. PRO Unlimited Gear Locker items and jobs, what-if comparisons, PDFs and share cards, custom rope profiles and widgets. Pro does not change model validity or calculation correctness. Choose a one-time Lifetime purchase or annual subscription. Existing monthly subscribers retain access while their Apple-verified entitlement is active. Any trial applies only when Apple confirms eligibility; the purchase screen shows the actual price and offer. Subscriptions renew unless cancelled in Apple subscription settings before renewal. Privacy Policy: https://app-legal-pages.vercel.app/snubline/privacy Terms of Service: https://app-legal-pages.vercel.app/snubline/terms

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Clarified educational-only use and numerical comparisons. The provisional model has no independent professional validation and must not guide field operations, equipment selection or load-safety decisions. Improved Pro plan selection, purchase and restore feedback, and a new educational comparison animation. Annual and Lifetime are the current purchase options; historical subscriptions remain supported. Comparison PDFs now use Letter-sized pages with automatic continuation for long notes and records. Improved numeric input, keyboard dismissal, and Settings support links.

Version 1.1

The developer, 慧慧 高, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    慧慧 高
    Size
    5.1 MB
    Category
    Productivity
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    Languages
    English
    Age Rating
    4+
    In-App Purchases
    Yes
    • Monthly $2.99
    • Annual $11.99
    • Lifetime $29.99
    • Learn More
    Copyright
    © 2026 Huihui Gao
  • Privacy Policy

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