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Do you think all knots are created equal?
There are a lot of publications available that contain information about knots and knot strength. For that reason we will not include much information here, except to say that knots reduce the overall strength of a rope. Therefore, whenever possible use a tensionless hitch around a cylindrical object with at least a 4" diameter. Four inches is the magic number for maintaining full strength in a rope up to 5/8". Any bend tighter than 4" reduces the strength of rope because it stresses the rope in flexure, the fibers weaker direction. Here is a list of some common knots and the translating remaining rope strength:
NO Knot 100%
Double Fisherman's 65-70%
Bowline 70-75%
Water knot 60-70%
Figure 8 on a Bight 75-80%
Clove hitch 60-75%
Overhand 60-65%
This is based on a well tied knot, a knot that has been dressed. If the knot is poorly tied and is not dressed, the strength of the rope will greatly decrease from the numbers above.
A great reference for knots, anchors, belay setup and much more is the Technical Rescue Field Operations Guide Third Edition by Tom Pendley.
Another great book is the Knots for the Rescue Service by Pat Rhodes
Check with your instructor to verify the correct knot, bend and hitches for your use.
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