Mooring systems for marine energy converters

John F. Flory, Stephen J. Banfield, Isabel M L Ridge, Ben Yeats, Tom Mackay, Pengzhu Wang, Tim Hunter, Lars Johanning, Manuel Herduin, Peter Foxton

    Research output: Chapter in Book/Conference paperConference paper

    2 Citations (Scopus)

    Abstract

    This paper discusses several new technologies for mooring floating marine energy converter (MEC) devices, such as wave energy generators, tidal current turbines and floating wind turbines. The principal mooring component is a special nylon fiber rope which provides cyclic tension fatigue endurance much superior to that of conventional nylon ropes. The nylon fiber is treated with a new proprietary coating which has excellent wet yarn abrasion properties. The parallel-subrope type rope construction further reduces internal abrasion. Extensive laboratory testing was carried out on this new nylon rope design. Cyclic tension fatigue tests were conducted at mean loads and load amplitudes typical of actual service conditions and at higher mean loads and amplitudes. These tests demonstrate that the special nylon rope has essentially the same, desirable stretch characteristics as conventional nylon rope and has much better endurance performance. The mooring connection to the floating MEC device consists of a high-modulus fiber rope pendant which passes through a low-friction bell-mouth nylon fairlead on the MEC device. This eliminates the use of heavy, unreliable chain in this critical connection. A unique bag anchor system would be used on sand, clay, rock and other sea beds in which conventional drag embedment anchors and driven piles are impractical. The bag anchor consists of a large abrasion resistant carcass with lifting straps and top closure. The bag is transported to site in a collapsed form and is filled with local sand or aggregate to provide ballast weight. Several or many such bags are enclosed within a fiber rope net for deployment and are grouped together for connection to the mooring line. The paper will be of particular interest to designers of moorings for MEC systems in shallow water and severe wave environments. It will also be of interest for other mooring applications.

    Original languageEnglish
    Title of host publicationOCEANS 2016 MTS/IEEE Monterey, OCE 2016
    EditorsJill Zande, Bill Kirkwood
    PublisherIEEE, Institute of Electrical and Electronics Engineers
    ISBN (Electronic)9781509015375
    ISBN (Print)9781509015375
    DOIs
    Publication statusPublished - 28 Nov 2016
    Event2016 OCEANS MTS/IEEE Monterey, OCE 2016 - Monterey, United States
    Duration: 19 Sep 201623 Sep 2016

    Conference

    Conference2016 OCEANS MTS/IEEE Monterey, OCE 2016
    CountryUnited States
    CityMonterey
    Period19/09/1623/09/16

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