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#Industry News

Samson’s rope on the hotplate

Rope has to deal with a lot of harsh realities: both heat and ultraviolet do their level best to degrade the fibres.

So, Samson conducted a number of trials on its KZ100 synthetic rope in order to investigate the effect of heat on breaking strength.

These tests explored what happened when the rope was exposed to environmental temperature conditions ranging from ambient air temperatures of around 25°C all the way up to a cooking 70°C, which exceeds the recommended maximum operating temperature (60°C) for KZ-100 by a good 10° margin.

Samples were exposed to these various elevated temperatures for 30 minutes, utilizing an apparatus which ran in line with the break test machine, allowing the temperature to be maintained.

So, immediately following this period of heat soak, load was applied to the test samples until failure occurred - the resulting peak loads provide an estimate of the instantaneous strength loss within the given temperature ranges. The results were encouraging, as the results showing 100% strength both at 25°C and 30°C, 98% at 40°C, 96% at 50°C, 94% at 60°C, 92% at 70°C.

But what about longer-term effects? Other Samson test results indicate that ropes made with Dyneema fibre stored in ambient temperatures up to 75°C for extended periods have been shown to have no significant reduction in strength when then tested at room temperature.

As rope has more than ‘ambient’ temperatures to cope with, 70°C hot plate test results for three of Samson’s ropes made with 100% Dyneema, high modulus polyethylene (HMPE) and a Dyneema/polyester blend showed the nearby fibres reached a steady equilibrium somewhere between the heat source temperature and the 25°C ambient air temperature. While on the whole, results showed that the non-Dyneema fibres are more resistant to high temperatures than Dyneema or traditional fibres like polyester, extrapolating this to Samson’s KZ-100 (a blend that, besides a large proportion of Dyneema, also includes other fibres with different characteristics), showed that by inference, the KZ-100 blend should perform well and exhibit the same levelling-out of temperature, although it wasn’t tested directly.

Last but not least, KZ-100’s proprietary ultraviolet coating was put through its paces by accelerated UV testing (conducted conforming to ASTM G154). Florida takes its toll on the best onboard, so samples were tested in various intervals of simulated Miami, Florida sun; the worst case scenario being a simulation of no less than one year’s worth of constant exposure.

The results of tensile break tests confirmed the rope would do better than many crew members, maintaining 90% of its new rope strength even after a whole year of Miami operation.

Details

  • United States
  • Samson