Knot Strength Chart

How Strong are Different Knots

Below is a strength of knot chart that was taken with thanks to, The Art of Knotting and Splicing – United States Naval Institute.

“The following strength of knot table show the efficiency or relative strength normally to be expected of twelve common knots when tied in manilla rope up to 1″ in diameter.”

Knot Name

Overhand Knot
Figure of Eight Knot
Reef or Square Knot
Sheet Bend
Bowline Knot
Fisherman’s Knot
Fisherman’s Bend
Two Half Hitches
Timber Hitch
Short Splice
Eye Splice

Knot Strength %

45%
45%
50%
50%
60%
65%
65%
65%
70%
90%
95%

Strength of Knot Chart Additional

I find it rather odd that despite many activities still use rope, but there is so little information on the actual strength of knots During my research I found that there was very little official documented information on the strength of knots. So below is some knot strength information that I have gathered from various places accross the net.

The information posted on this page should only be used as a very rough guide. I have no actual test data that confirms whether or not the above or below charts are 100% accurate.

Knot Name

Adjustable Grip Hitch
Alpine Butterfly
Anchor Bend
Bowline
Bowline on the Bight
Carrick Bend
Clove Hitch
Figure Eight Knot
Figure Eight Loop
Figure Eight Loop Inline
Fisherman’s Knot
Overhand Knot
Overhand Loop
Reef or Square Knot
Sheepshank
Sheet Bend
Timber Hitch
Two Half Hitch
Water Knot

Knot Strength %

80%
75%
60%
60%
60%
55%
60%
48%
80%
75%
65%
45%
85%
45%
45%
48%
70%
75%
60%

Strength of Knot Information

Please do keep coming back to this page, as it will be updated every time I find new information on the strength of knots.

The old Strength of knot chart

Knotting Book Recommendations

Books
Decription
USA
UK
Ashley Book of Knot (ABoK) This really is the bible of all knots, consisting of over 600 pages and over 3000 diagrams Rating:
Shop USA
Shop UK
Knot Craft and Rope Mats: 60 Ropework Projects Including 20 Mat Designs by Des Pawson Rating:
Shop USA
Shop UK
The Marlinspike Sailor by Harvey Garret Smith If you are starting to build a collection of knotting books, then this is a great one to have in your library. Rating:
Shop USA
Shop UK
A Practical Guide to Tying Knots by Geoffrey Budworth This book contains 75 bends, hitches, knots, bindings, loops, mats, plaits, rings and slings. Rating:
Shop USA
Shop UK

Comments

Knot Strength Chart — 9 Comments

  1. Pingback: Most Useful Knots – Jackson Raila: Straight To The Point

  2. I think the important missing knot is “ROUND TURN & 2 half hitches”. Several tests (including modern ones like the RYA) show it is perhaps the only knot that doesn’t weaken the rope.
    The White Water rescue people have a “NO KNOT” which is the “ROUND TURN & 2 half hitches” without the 2 half hitches 😮 ie it’s just wrapping a couple of loops round a tree.
    Not sure if your tests are just the 2 half hitches which is a LOT weaker than “ROUND TURN & 2 half hitches”

    • I find it very strange that there is no up-to-date official information on knot strength. It really would not be too difficult to setup a machine and test all knots? Thanks for taking the time to view and also make a comment, very much appreciated.

    • The round turn & 2 half hitches is a safe knot and easy to tie – i have been down a cliff face after a faller on a hauser secured by a bowline round a tree trunk

  3. Great info! Thanks! What are the percentages relative to? Do they represent the strength of the knots as a percent of the TENSILE or WORKING strength of a <1" manilla rope?

    • Hi CC,

      You’re not the only one who wonder about that ratio. The 100% efficiency (the strength) is the “Maximum Load” specified by the manufacturer that is written on the package or in the details on Internet. A “Maximum Load” is always tested with a new rope before being rolled for packaging. They perform it on a straight rope.

      Say the Maximum Load is specified at 100 kg. The chart above estimates the strength of a “Clove Hitch” at 60%. That means that the rope will snap at 60 kg.

      Since a rope is flexible, it keeps its 100% efficiency until the diameter of a loop is less than 4 Times The Width Of The Rope. You can verify that statement this way:

      1. Make a loop greater than 4 Times The Width Of The Rope.

      2. Reduce the diameter very slowly until you feel a subtle resistance.

      3. Measure the diameter.

      4. Reducing further the diameter increases the resistance.

      When the inner part of a bend reaches its maximum contraction, its acts as a fulcrum of a bubble ‘class one’ lever that stretches forcefully the circumference of the bend with an increasing mechanical advantage; like breaking a stick with your two thumbs joined together.

      According to rescue people, a loop looses 25% per width of the rope, e.g.: a loop of 3 times the width has 75% efficiency, 2 times the width has 50% efficiency, 1 times the width has only 25% and the efficiency of a very tight bend is next to zero.

      We can apply this theory to the chart above. Here, the chart rates a Bowline at 60% efficiency. It make sence since the pulling force squeezes the first loop in which the rope passes two times in it, i.e., 50% efficiency.

      Bottom line. It Is Highly Recommended To Load A Rope Under 50% The “Maximum Load” Specified By The Manufacturer !!! Even less if the rope is not as good as new!

      Daniel M. Bourdon , creator of knots and hitches.

  4. Sorry for this orthographic error:

    its acts as a fulcrum of a DOUBLE ‘class one’ lever…

    Dan

  5. Pingback: How to Tie the Sheepshank

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