Once the decision to switch to non-jacketed ropes was made, BW FM considered several manufacturers, but opted for Samson’s AmSteel®-Blue mooring lines, made with Dyneema® SK78. Manufactured by DSM, Dyneema® SK78 is specifically designed to withstand the long-term load bearing requirements found in extreme applications, and shows consistent quality, achieving its claimed strength of 35 cN/dtex batch after batch. In fact, AmSteel®-Blue mooring lines made with Dyneema® SK78 offer better bend fatigue characteristics than other grades of HMPE, and improved service life in applications where long-term static loads can lead to rope elongation. Just what BW FM needed.
Dyneema® SK78: resistant to abrasion, bending fatigue, and creep
Ropes made with Dyneema® SK78 are typically used in applications where lightweight strength plus one or more of the following criteria are needed: resistance to abrasion, bending performance, resistance to compression fatigue and resistance to creep. In the case of BW FM, the primary requirements were abrasion resistance, resistance to bending fatigue and creep resistance.
Take abrasion: mooring a large vessel involves running the rope through fairleads and over capstans. It’s a rough, tough life, and the external abrasion on the rope eventually degrades and breaks the fibers. Ropes made with Dyneema® SK78 have a proven abrasion lifetime that is four times longer than that of generic HMPE ropes. And even higher abrasion-resistance can be achieved by applying a proprietary coating to the ropes.