Far-field vessel wakes in Tallinn Bay

Kevin Parnell, Nicole Delpeche, Ira Didenkulova, Tony Dolphin, Ants Erm, Andres Kask, Loreta Kelpšaite, Dmitry Kurrenoy, Ewald Quak, Andrus Räämet, Tarmo Soomere, Anna Terentjeva, Tomas Torsvik, Inga Zaitseva-Pärnaste

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

The properties of wave fields induced by high-speed ferries and recently introduced conventional ferries with increased cruise speeds are analysed for a site in Tallinn Bay, the Gulf of Finland, the Baltic Sea, located about 3 km from the sailing line and up to 8 km from the wave production area. The analysis is based on high-resolution profiling of the water surface for about 650 wakes from fast ferries, measured during 4 weeks in June-July 2008. The new large conventional ferries with cruise speeds of 25-30 knots (~45-55 km/h) sail at near-critical speeds along extensive sections of eastern Tallinn Bay, and excite wakes equivalent to those of high-speed ferries. The peak periods of these wakes are between 10 and 13 s. The typical daily highest ship wave is approximately 1.2 m, measured prior to wake breaking. The largest recorded ship wave in calm conditions had a height of 1.5 m and in the presence of some wind wave background 1.7 m. The cumulative impact of ship wakes results in a gradual increase in the suspended matter concentration in near-bottom water over the course of a day. The largest and longest ship waves produce considerable wave runup at the coast and prevent several coastal sections from achieving an equilibrium state. The largest ship waves have an asymmetric shape both in terms of the water surface elevation above and below the mean level and in terms of the shape of the wave front and back. The overall intensity of anthropogenic waves has remained at the same level as it was in the year 2002, although the ships that produced the highest waves in the past are no longer in service.
Original languageEnglish
Pages (from-to)273-302
Number of pages30
JournalProceedings of the Estonian Academy of Sciences: Engineering
Volume14
Issue number4
DOIs
Publication statusPublished - 2008

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