Knot Strength

[fire-inst]

Does anyone have or know where to find a list of the percentage of strength a knot loses when tied. I have heard that such and such a knot loses _____% of the strenght of the rope. I have looked but so far have found nowhere to find this information.

[weir33]

On this site you will find adobe pfd manuals that have a good section on ropes / knots and the and how to care for rope including % .

<br /><a href="http://www.ccg-gcc.gc.ca/sar/nsm-msn/main_e.htm" target="_blank">http://www.ccg-gcc.gc.ca/sar/nsm-msn/main_e.htm</a>

This link has some good stuff I have THE KNOT BOOK which is quite good.It has step by step colour pictures. <a href="http://www.dur.ac.uk/~dds8sgg/SCOUTING/IGKT.html" target="_blank">http://www.dur.ac.uk/~dds8sgg/SCOUTING/IGKT.html</a>

<br />hi me again try searches for... " Knots for Mountaineering " ( good results ) and "international Knots "

[ 01-25-2002: Message edited by: weir_33 ]</p>

[Techresq]

fire-inst,<br />Here are the weakens ther rope per CMC Rope Rescue Manual (second edition). This is what I go by when I teach a Rope Rescue Classes.

Bends<br />Double Fisherman’s Knot 21%<br />Figure 8 Bend 19%

Loops

Figure 8 Loop (with a bight) 21%<br />Figure 8 Loop (follow through) 19%<br />Double Figure 8 Loop 18%<br />Figure 9 Loop 9%<br />Inline Figure 8 25%<br />Bowline 33%<br />Butterfly 25%<br />Overhand Loop (with a bight) 15%<br />Overhand Double Loop 26%

Rope with a loop in it

Figure 8 Loop 35%<br />Inline Figure 8 Loop 41%<br />Butterfly Loop 31%

Knots in Web

Water Knot 36%<br />Overhand Loop 35%<br />Figure 8 Loop (with a bight) 30%<br />Figure 8 Loop (follow through) 26%

I hope this helps you out. If you have any question please feel free to drop me an E-mail.

David Gerrer<br />Owner / Lead Instructor<br />Technical Training Solutions, LLC<br /><a href="http://www.TechTrngSols.com" target="_blank">www.TechTrngSols.com</a>

[hydratank]

Try "Knots for Mountaineering"<br />by: Craig Luebben<br />Pub: Evergreen Press

This gentleman has a Masters in Mechanical Engineering, Holds several Patents for climbing devices, and has written a complete series on all aspects of climbing, including "Self Rescue" etc.

Craig is extremely articulate and thorough in addition to being really down to earth. He is a Professional Mt. Guide and is developing and implementing new techniques all the time. A valuable resource for the fire service.

I wager he will return e-mail. His address should be available from the Publisher.

Good Luck and remember-GRAVITY KILLS.

[fire-inst]

Thanks Techresq that was what i was looking for.

[MtnRsq]

Remember - knot strength is not the only thing to consider.

The appropriateness of the knot for the given application MUST also be considered.

Also - remember that wet ropes, etc. don't behave the same way as dry ropes. How well a knot is tied matters - is it well dressed and finished?

The most "efficient" knot in the world, poorly tied and used inappropriately can kill you (or someone else) just as a "weak" knot can.