Testing & evaluation

Retired after 3997 jobs

Case Svitzer TOW LINE

Dynamica Tow lines offer excellent performance

After 3997 jobs, Svitzer UK retired their Dynamica Tow Lines allthough their company police is to retire after only 2000 jobs.

The extra 1997 jobs are made possible because of our manufacturing process; the tow lines are manufactured with HMPE/Dyneema® and pre-stretched in the heat stretching unit meaning that they gain strength when under repeated tension as the fibres are organised due to the stress.

Svitzer not only order new Dynamica Tow lines, but returned the retired ones for testing and evaluation.

“We are very pleased with the performance of our Dynamica Tow lines. They have been in service since installation and have completed 3200 jobs. It is our company policy to ‘end for end’ the towline after 2000. So we have about 800 more jobs until the 4000 limit. The main line is connected to a working pennant (20 m x 56 mm Dyneema jacketed line). These pennants are replaced every 2000 jobs (end for ended after 1000 jobs).”

Andy, Master at Svitzer

We tested the retired tow lines for residual strength and generel condition during a visual inspection and break tests.

Visual inspection

The visual inspection showed that the rope and cover was in very good shape, much better than could be expected. It was clear that the customer had taken good care of the tow lines.

Test bed at Dynamica Ropes

Break test

We performed 4 different break tests:
- Outer eye (cow hitch eye) + new eye
- Inner eye
- Tests approx. 60 m down the rope from each eye end (2 new splices)

test report used rope analysis

In the test results above the “X” marks where the rope parted.

Dyneema fibres

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