The Netherlands: Ropes with DYNEEMA® Keep “PUSH COMBINATIONS” Together

Ropes made with Dyneema^®, ultra-high molecular weight polyethylene (UHMWPE), are proving a safe and secure alternative to steel wire rope for connecting barges and vessels in “push combinations” working on inland waterways.

In push combinations, the barge and the unpowered vessel in front of it have to be tightly lashed together to prevent any articulation. Traditional steel wire rope (SWR) is not only labour intensive, but can also be dangerous for the crew if individual strands snap, creating so-called fish hooks. The hard and heavy SWR can also damage decks, bollards and other equipment, leading to costly repairs and paint jobs.

The push combination ‘Norma’ has been operated by Captain Grinwis and his crew on the river Rhine between Basel and Rotterdam since July 2007. With a total length of 179m, a width of 11.5m and a capability of carrying loads of up to 336 TEU (Twenty-foot Equivalent Units), it uses four “Eurolest” ropes made with Dyneema^® by Lankhorst Ropes in Sneek, The Netherlands. Captain Grinwis and his crew – all of whom have had a lot of previous experience with SWR on other push combinations – say they are extremely satisfied with the new solution offered by ropes.

The connecting ropes made with Dyneema^® are seven times lighter then SWR, yet offer greater strength at a comparable diameter, resulting in higher handling speeds and the involvement of fewer crew members. The ropes float on water and do not damage deck equipment, considerably reducing the need for repairs and paint jobs.

“Handling the ropes with Dyneema^® is very simple,” says Captain Grinwis. “Connecting the barge can take just five minutes; in some cases disconnecting can take only two. Moreover, it requires just one crew member to do the job and there is no risk of fishhooks.”

The barge needs to be bound very tightly to the push vesseI in order to avoid unwanted swirling of the barge and to maintain sailing speed. Because of their very low elongation, the lines with Dyneema^® offer the advantage that once connected, tension within the ropes needs hardly any readjustment. “An occasional single click of the winch is often all that is required,” says Grinwis.

Marco Brinksma, Account Manager at Lankhorst Ropes adds: “Extensive tests during the start-up phase confirmed the outstanding performance of the ropes. Even under harsh conditions, i.e. high speed sailing combined with short and rapid turns of the push combination, independent movement of the container barge was kept to a minimum. The ropes did not slip and tension did not need to be readjusted.”

The ropes were originally supplied with polyester jackets, but these proved susceptible to wear and tear around bollards. They have since been equipped with highly abrasion resistant covers made with Dyneema^®, which have proven much more reliable and durable.

After seven months in use, one of the ropes was subjected to test that showed its residual strength was only two percent lower than the original minimum break load (MBL). Taking into account that the rope broke in the test at its weakest point – the splice – this was an outstanding result. Another rope was tested after three years of continuous use. Despite the fact that the cover and core of the rope were damaged, a residual strength of approximately 70% of its original MBL was recorded – a similarly remarkable result. The other ropes are undamaged and are still in service.

About DSM Dyneema

DSM Dyneema is the inventor and manufacturer of Dyneema^®, the world’s strongest fiber^™. Dyneema^® is an Ultra High Molecular Weight PolyEthylene (UHMWPE) fiber that offers maximum strength combined with minimum weight. It is up to 15 times stronger than quality steel and up to 40% stronger than aramid fibers, both on weight for weight basis. Dyneema^® fiber floats on water and is extremely durable and resistant to moisture, UV light and chemicals. The applications are therefore more or less unlimited. Dyneema^® is an important component in ropes, cables and nets in the fishing, shipping and offshore industries. Dyneema^® is also used in safety gloves for the metalworking industry and in fine yarns for applications in sporting goods and the medical sector. In addition, Dyneema^® is also used in bullet resistant armor and clothing for police and military personnel.

UHMWPE fiber from DSM Dyneema is produced in Heerlen (The Netherlands) and in Greenville, North Carolina (U.S.A.). DSM Dyneema is also a partner in a high modulus polyethylene (HMPE) manufacturing joint venture in Japan.

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Source:DSM Dyneema, February  15, 2011; Image: