WATER – IT’S EVERYWHERE, BUT HOW MUCH OF IT DO WE WANT TO CARRY IN OUR ROPES?
After carrying literally tons of rope over the years, I have noticed a difference in the weight of similar lengths of rope, not just between thicknesses, but between materials as well. Some ropes feel like they hold a lot more water than others. I have also noticed that some ropes take a lot longer to dry, even in summer.
I have been told on numerous occasions that Polyester absorbs less water then Polyamide. I have no idea why, so I thought I would put it to the test. The ropes are a bit random, but hopefully some information will be gained from this simple test.
Test Details:
Weather Conditions – Humidity approx 80%. Temperature range from around 8 – 15 degrees Celcius. Hanging under shelter, in the shade.
Testing Method – Cut 1 metre lengths of rope. Weigh dry rope. Saturate rope – fully immersed for 1 hour. Re-weigh saturated rope. Re- weigh at intervals. Kitchen scales were used to weigh the rope. Each measure was checked twice.
Ropes hung vertically – see photos. (I know you are not going to carry your rope like this, but this is how I chose to do it for the experiment!)
I used these ropes because they are what I had available.
ROPE WEIGHT COMPARISON – POLYESTER VS POLYAMIDE (OLD + NEW)
|
ROPE TYPE |
ROPE |
DRY |
WET |
DRIP DRY 30 MINS |
DRIP DRY 15 HRS |
DRIP DRY 24 HRS |
|
POLYAMIDE (NYLON) |
Kordas Dana 9mm Canyon Rope (used 50 + times, two years old) |
60gms |
82gms +36.66% |
80gms +33.33% |
74gms +23.33% |
63gms +5% |
|
Kordas Dana 10mm Canyon Rope (new) |
72gms |
86gms +19.44% |
85gms +18.05% |
81gms +12.05% |
76gms +5.55% |
|
|
Beal 11mm Climbing Rope (20 years old) retired |
71gms |
92gms +29.57% |
85gms +19.71% |
80gms +12.67% |
72gms +1.4% |
|
|
POLYESTER |
Stirling HTP 9mm (used 50 + times, two years old) |
67gms |
90gms +34.32% |
89gms +32.83% |
82gms +22.38% |
71gms +5.97% |
|
Donaghys – Abseil Braid 10mm (10 years old) |
96gms |
132gms +37.50% |
125gms +30.20% |
119gms +23.95% |
105gms +9.37% |
Percentage weight gain from original weight – shown in red for each rope.
Points of Interest :
- – In all cases the nylon rope drained faster than the polyester rope. (It would have been good to have some new HTP rope)
- – Interestingly, the Beal dynamic rope drained the fastest – it is polyamide.
- – The Kordas Dana 9 started off 11.66% lighter than the Stirling HTP (I was surprised).
- – The 10mm dry treated new Kordas is actually lighter than the 9mm HTP when wet.
- – Both Kordas ropes are dry treated (the 9mm is 2 years old, so there is some loss of ‘dry treatment’ over time).
- – The Donaghy’s rope is nearer 10.5mm, although advertised as 10mm. This polyester rope added the highest proportional weight.
- – My thoughts are that there is a correlation between the density of a rope, the quantity of water it holds, and how fast it drains.
– A more thorough test could be very interesting. There are lots of variants – if you have a selection of new and old ropes + some spare time ……
Rope getting a thorough wetting before initial weighing.
Hanging up to drip dry before weighing at
regular intervals.
Contact email: pete@accessgear.net
For full PDF information click here – Access Gear Rope Weight Comparison – 9_7_17