An overhand knot passes the end of a strand through a loop; its closed counterpart is a trefoil. Explore a loose, flat projection with a tracing marker and measure its sampled centerline. Drawing dimensions do not determine rope strength, safe load or the length needed to tie a physical knot.
Loose-Knot Drawing Calculator
Choose a drawing width, height, tail extension and polyline sample count. The worksheet measures only its declared schematic centerline; it is not a tying, inspection or load-rating tool.
Equation Used
- W and H scale an illustrative trefoil projection; they are not knot dimensions under load.
- N divides a fixed open parameter interval into equal steps and controls numerical polyline resolution only.
- The reported crossing count is the three-crossing topology of the corresponding closed overhand/trefoil described by the cited university source.
- Rope construction, diameter, dressing, set, friction, bends, loads, shock, cyclic behavior, slippage, strength, safety factors and suitability are excluded.
Adjust the drawing scale, tail extensions and sampling resolution to explore an illustrative open trefoil projection. The marker traces the fixed strand; it does not simulate tying, tightening or loading.
A loop, an end pass and a three-crossing closed counterpart
U.S. Army TC 4-13.17 identifies the overhand as the simplest commonly used knot and documents use at the end of a line or as part of another knot. The Army Mountain Warfare School guide describes forming a loop and placing the running end through it.
Colorado State University's biochemistry tutorial uses the overhand to distinguish physical knots from pseudoknots and states that the corresponding closed representation is a three-crossing trefoil. The animation follows one continuous illustrative strand; it does not tighten or load it.
Documented context, not operating advice
The Army transport manual documents the overhand as a small stopper topology and as a component of other knots. The National Park Service technical rescue handbook describes it as a simple single-strand knot and notes that rescue practice distinguishes a double overhand for backup use.
Those sources show that form, material and context matter. This page does not authorize a knot for climbing, rescue, arboriculture, sailing or lifting.
Declared sampled drawing only
The curve is an open sampled trefoil projection with two straight schematic tails. Increasing N refines only the numerical polyline. Ls is not rope length or a tightened-knot dimension.
Declared diagram example
At W=160 mm, H=120 mm, T=60 mm and N=96, the worksheet reports the fixed three-crossing closed counterpart, 120.0 mm of declared tail extension and 98 schematic straight segments, together with the computed sampled drawing length.
No material property, breaking strength or safe load is inferred.
What this diagram cannot determine
A flat projection cannot determine contact pressure, friction, dressing, set, bend severity, capsizing, slippage, cyclic response or failure. A user-selected efficiency factor is not a rope test or certified rating.
Rope strength and the behavior of a tied knot depend on material, construction, condition and loading. This centerline calculation contains none of those properties and cannot provide a load rating or application-specific tying guidance.
Overhand-knot questions
Does the sampled length tell me how much rope to cut?
No.
Does the three-crossing count rate knot strength?
No.
Does animation show tightening?
No; a marker only traces one fixed declared centerline.
Can I enter a rope MBS or efficiency?
No. The inputs describe a sampled drawing, with no rope breaking-strength or efficiency model.
Can this page select a knot for a safety system?
No.
Overhand-knot references
- U.S. Army TC 4-13.17, Block and Tackle, Wire Rope, and Marlinspike Seamanship: official doctrine identifying the overhand, its stopper role and its relationship to other knots.
- U.S. Army Mountain Warfare School Knot Guide: official guide documenting the loop-and-end-pass construction and inspection context.
- Colorado State University, Knots vs. Pseudoknots: university tutorial identifying the overhand and its three-crossing closed trefoil representation.
- U.S. National Park Service Technical Rescue Handbook: handbook distinguishing the simple overhand from double-overhand backup practice.
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