+x neilm - 5/16/2019+x Simon Currin - 5/16/2019NeilWas it a figure of eight that failed on the Series Drogue that led to the loss of a Golden Globe Boat?Simon+x neilm - 5/15/2019There is some good data on the extent to which various knots weaken ropes athttp://caves.org/section/vertical/nh/50/knotrope-hold.html To summarize, double and single sheet bends give only about 50% of the rope strength, and then only if backed up by half hitches to resist pulling out.The fisherman's knot gives 75% strength, and is safer with half hitch backupsFor loops, a bowline is about 65% of a splice, and double figure eight loop about 75%Splices have the full strength of the rope, if well done.On a related issue, an article on the impact of water on strength of climbing ropes shows that wet nylon has only about 30% of the strength of dry nylon when subject to abrupt shock loads, such as a falling rock climber. I suspect the situation is not quite so bad in the less abrupt shock loads seen in anchor rodes. Data on tests would be very interesting.The failure was at a point where both legs of the bridle (terminated in eyesplices) were cow-hitched to a loop made with a figure of eight. Seems that the figure eight failed. My info is mostly from John Harrie's article at https://www.morganscloud.com/2019/04/15/susie-goodalls-series-drogue-failure/ Two cow hitch/splices were sharing the load, whereas the figure eight was on its own.
+x Simon Currin - 5/16/2019NeilWas it a figure of eight that failed on the Series Drogue that led to the loss of a Golden Globe Boat?Simon+x neilm - 5/15/2019There is some good data on the extent to which various knots weaken ropes athttp://caves.org/section/vertical/nh/50/knotrope-hold.html To summarize, double and single sheet bends give only about 50% of the rope strength, and then only if backed up by half hitches to resist pulling out.The fisherman's knot gives 75% strength, and is safer with half hitch backupsFor loops, a bowline is about 65% of a splice, and double figure eight loop about 75%Splices have the full strength of the rope, if well done.On a related issue, an article on the impact of water on strength of climbing ropes shows that wet nylon has only about 30% of the strength of dry nylon when subject to abrupt shock loads, such as a falling rock climber. I suspect the situation is not quite so bad in the less abrupt shock loads seen in anchor rodes. Data on tests would be very interesting.
+x neilm - 5/15/2019There is some good data on the extent to which various knots weaken ropes athttp://caves.org/section/vertical/nh/50/knotrope-hold.html To summarize, double and single sheet bends give only about 50% of the rope strength, and then only if backed up by half hitches to resist pulling out.The fisherman's knot gives 75% strength, and is safer with half hitch backupsFor loops, a bowline is about 65% of a splice, and double figure eight loop about 75%Splices have the full strength of the rope, if well done.On a related issue, an article on the impact of water on strength of climbing ropes shows that wet nylon has only about 30% of the strength of dry nylon when subject to abrupt shock loads, such as a falling rock climber. I suspect the situation is not quite so bad in the less abrupt shock loads seen in anchor rodes. Data on tests would be very interesting.