The Most Useful Rope Knots
for Boaters to Know

Bentley Smith, MD
adapted from Dave Root

The best knot:

  • does the required job,

  • decreases the breaking strength of a rope as little as possible,

  • is easy to tie,

  • is easy to remember how to tie properly,

  • is secure enough not to come loose,

  • is easy to untie even after being under a heavy load.

Background Information

Every rope has a "breaking strength," which means that, if we place a heavy enough strain on a rope, then it will eventually break. The Safe Working Load of a rope is considered to be one-fifth (1/5) of the rope's breaking strength, according to BoatSafe.com. Knots can reduce the breaking strength of a rope, sometimes by 25%, 50%, or more. Since we trust our lives to the knots that we tie, it is surprisingly difficult to find solid research on the strength of the main knots in use today. The values listed in the table below refer to the breaking strength percentage that remains after that specific knot has been tied:

  Source Source Source Source Source Source Source *
Adjustable Grip Hitch               80% or more
Alpine Butterfly             75%  
Bowline 60% 70-75%   70-75% 67-75% 60% 67% 60% or more
Clove Hitch 75% 60-65% 60-65% 60-65%   75%   60-75%
Figure-Eight Knot 50% 75-80% 70-75% 75-80%   48% 81%  
Fisherman's Bend
(Anchor Bend)		 70% 60-65%   60-65% Over 5/8" dia. ring
55-65%
Over 4" dia. post
80-90%		 70%    
Overhand Knot 45% 60-65% 60-65% 60-65%   45%    
Reef Knot (Square Knot) 45% 43-47% 45%   43-57% 45%   45%
Sheet Bend         48-58%     55%
* Geoffrey Budworth is a co-founder of the International Guild of Knot Tyers. He was responsible for updating "the knot enthusiasts' bible," The Ashley Book of Knots (by Clifford Ashley). The values in the last column are from Budworth's book, The Complete Book of Knots.

 

Terminology

When a rope circles around and then crosses over itself, this is often referred to as a "loop":

A "bight" is essentially an open loop:

After you tie a knot, it is important to "dress" the knot properly. This means ensuring that all knot parts are correctly placed, and that the rope doesn't cross itself unnecessarily. Each time a rope is sharply bent over something (such as a cleat), this bend can stress and tear some rope fibers. This is why you should dress your knots properly. Otherwise, you may weaken a rope without realizing it, and in some cases you might be trusting your life or property to a significantly weaker rope. The first picture below shows an improperly-dressed knot. The second image depicts the same knot which has been properly dressed:

Again, if a knot is not properly dressed, then it can weaken the rope more than a properly-dressed knot can. Also, the knot should be "set" by being tightened before it is used. Otherwise the knot might "slip" or "spill" or "capsize, " and become unstable or fall apart, which can potentially be disastrous.

Knowing the best knot to use and properly tying it and properly dressing it and properly setting it can save your life or save someone else's life or protect your valuable possessions from damage.

 

Bends Hitches Loop Knots

 

References and Links

There are many people who can be considered experts in knots. In this series of articles I have mainly quoted from two recognized authorities on knots:

  1. Clifford Ashley, whose book, The Ashley Book of Knots, contains 3,900 different knots and 7,000 illustrations, and has been called the definitive reference work on knots and "the knot enthusiasts' bible."

  2. Geoffrey Budworth, who is one of the co-founders of the International Guild of Knot Tyers (see the link below) and who was responsible for updating and revising The Ashley Book of Knots by Clifford Ashley.

Here are several websites which provide a lot of information on knots.