Why knot strength tables disagree
Explainer · Last reviewed 2026-08-14
Published knot strength percentages contradict each other because the tests behind them differ in almost every variable that matters. FishingHQ does not publish a table, and this is the record explaining why.
SEARCH FOR A KNOT STRENGTH TABLE AND YOU WILL FIND SEVERAL, AND THEY WILL NOT AGREE. The same knot in the same nominal line appears at eighty per cent in one and at ninety-five in another. Both numbers may be honestly measured. The disagreement is in the testing.
WHAT VARIES BETWEEN TESTS, all of which move the result substantially.
THE LINE. Not the label — the actual line. Two spools marked twenty pounds from different manufacturers differ in diameter, surface finish, stiffness and true breaking strain. A knot's retention percentage is a property of the knot AND the line together, and quoting it without naming the exact line is quoting half a result.
WHO TIED IT. Knot strength is dominated by tying quality. A test where one person ties every sample carefully in a workshop measures that person's best work, not what the knot achieves in the dark with cold wet hands.
WHETHER IT WAS WET. Materially changes the result, and is frequently not stated.
HOW THE LOAD WAS APPLIED. A slow steady pull to failure and a sudden shock load produce different numbers and different failure modes, and fishing contains both.
HOW MANY SAMPLES, AND WHAT WAS REPORTED. A mean of thirty tests and the best of five are different claims. Knot testing has high variance, and small samples with the outliers discarded produce flattering results.
WHAT WAS COUNTED AS FAILURE. Slipping and breaking are different events. Some tests record only the load at which the sample separated, which conflates them.
WHAT IS ACTUALLY WELL ESTABLISHED, and it is less than a table implies: that a knot is always weaker than the unknotted line; that wetting and full seating improve retention; that slick materials need more turns; and that tying quality varies more between people than retention varies between good knots.
WHAT FOLLOWS PRACTICALLY. Choosing between two well-regarded knots on a five per cent published difference is choosing on noise. Learning one of them properly, tying it wet and seating it fully will beat that difference several times over. And the drag setting — which decides the maximum load that ever reaches the knot — matters more than the knot's rating does.
FISHINGHQ THEREFORE PUBLISHES NO STRENGTH TABLE. A table would present a precision that the underlying testing does not support, and would be indistinguishable on the page from one that does.
What a line class rating does and does not guarantee
There is one place in angling where line strength is genuinely standardised, and it is worth knowing about because it runs opposite to intuition.
Line sold to a stated CLASS, under the conventions used for record claims, must break at or BELOW its stated figure. A line labelled as a fifteen-kilogram class must not exceed fifteen kilograms when tested, because a record claimed on that class would otherwise have been made on stronger tackle than declared.
Line sold on strength has the opposite commercial incentive: exceeding the label is a selling point, and many lines do so comfortably.
So two spools bearing the same number, sitting on the same shelf, may be built to guarantee opposite things. That is not a defect in either; it is two conventions serving two purposes. It does mean that comparing knot test results across lines from different conventions is comparing results obtained on materially different material.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- IGFA International Angling Rules and World Record Requirements — International Game Fish Association (Angling or fisheries organisation)Relied on for: International angling rules including line class definitions, leader and double-line limits and the testing conventions behind them.States this directlyPassage read and verified
Where to go next
Related reading
- Line class and breaking strain ratingsLine built to a class is required to break BELOW its label and line sold on strength routinely exceeds it, so two tests on identically labelled line are not testing the same material.
- Line strength, diameter and knotsRetention percentages are a property of the knot and the line together, which is why quoting one without naming the other is quoting half a result.
What these connections rest on (2)
Practitioner consensus — 2 connections
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Line class and breaking strain ratings
A mechanism edge from a record to the reasoning beneath it. How knots and rigs behave is established practitioner knowledge converging across independent angling traditions, and is labelled as consensus rather than as tested result.
- Angling Times — Bauer Media (Specialist angling publication)Relied on for: Contemporary UK coarse and match angling practice as reported by practitioners, including rig and knot convention.States this directlyCitation checked — the work exists and is described correctly
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Contemporary UK sea angling practice as reported by practitioners, including rig construction, leaders and line choice.States this directlyCitation checked — the work exists and is described correctly
Line strength, diameter and knots
A mechanism edge from a record to the reasoning beneath it. How knots and rigs behave is established practitioner knowledge converging across independent angling traditions, and is labelled as consensus rather than as tested result.
- Angling Times — Bauer Media (Specialist angling publication)Relied on for: Contemporary UK coarse and match angling practice as reported by practitioners, including rig and knot convention.States this directlyCitation checked — the work exists and is described correctly
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Contemporary UK sea angling practice as reported by practitioners, including rig construction, leaders and line choice.States this directlyCitation checked — the work exists and is described correctly
How this compares
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Wetting, seating and tag ends: the three things that decide whether a knot holds
Two records a reader will be holding in mind at once, joined so that the distinction between them is visible rather than assumed.
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Comprehensive angling practice including knots, leaders, terminal tackle and the reasoning behind rig arrangements.States this directlyCitation checked — the work exists and is described correctly
- Still-Water Angling — MacGibbon & Kee, 1953 (Specialist angling publication)Relied on for: Stillwater angling practice including terminal tackle, hook holds and the mechanics of playing fish.States this directlyCitation checked — the work exists and is described correctly
More explainer
Not related to this page — just the rest of the section, because this record connects to very little and a short page should still lead somewhere.
Sources for this page
- IGFA International Angling Rules and World Record Requirements — International Game Fish Association (Angling or fisheries organisation)Relied on for: International angling rules including line class definitions, leader and double-line limits and the testing conventions behind them.States this directlyPassage read and verified
- Freshwater Fishing — Macdonald & Jane's, 1975 (Specialist angling publication)Relied on for: Comprehensive angling practice including terminal tackle, knots, leaders and the reasoning behind rig arrangements.States this directlyCitation checked — the work exists and is described correctly
- Sea Angler — Bauer Media (Specialist angling publication)Relied on for: Contemporary UK sea angling practice as reported by practitioners, including rig construction, leaders and terminal components.States this directlyCitation checked — the work exists and is described correctly
How FishingHQ labels evidence is explained in the evidence policy.