Polyester vs. Nylon Ropes – Which Absorb More Water?

How much water does a rope absorb? It has always seemed that polyester ropes hold less than nylon ropes, but is this actually true? How big is that difference? I decided to find out yesterday…

Rope Water Absorption Test – July 13, 2011

Test Method: At least 30m of a particular rope is coiled, weighed, then immersed in a cooler full of water, and held under by weights, for one hour (+10 min, – 0 min). The rope is removed and hung in the air for 10 minutes (+1 min, – 0 min), then weighed again “wet.” The two weights are compared.

Conditions: Summer conditions (85 deg F air temp, low humidity, no wind). Water at faucet temperature.

Test Samples: I tested three samples:

1. Nylon climbing rope: Beal Joker 9.1mm x 60m dynamic climbing rope, lightly used (about 20 pitches), in good shape. “Standard” treatment on this rope is DryCore.

2. Polyester canyoneering rope: Imlay 8.3mm Canyon Fire x 40m static canyon rope, lightly used (about 40 rappels), in good shape.

3. Polyester canyoneering rope: Imlay 9.2mm Canyonero x 60m static canyon rope, brand new.

Results:
- The used climbing rope absorbed 42.4% of its weight in water.
- The used canyon rope absorbed 22.4% of its weight in water.
- The brand new canyon rope absorbed 19.1% of its weight in water.

*** Yes, nylon absorbs more water than polyester, about twice.***

Tom Jones
Imlay Canyon Gear
July 13, 2011