The implications of frequent high-speed ferry wakes, Tallinn Bay, Estonia

Soomere, Tarmo, Parnell, Kevin E., and Didenkulova, Ira (2009) The implications of frequent high-speed ferry wakes, Tallinn Bay, Estonia. In: Proceedings of the FAST 2009 10th International Conference on Fast Sea Transportation (2), pp. 923-934. From: FAST 2009 10th International Conference on Fast Sea Transportation, 5-8 OCT 2009, Athens, Greece.

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Abstract

The almost-tideless Tallinn Bay, the Baltic Sea, is one of the few places in the world where high-speed ferries have been operating for about 10 years close to the shoreline, with up to 50 sailings per day. A new class of large, conventional, highly powered ships operating at ~50 km/h has been introduced in recent years. The properties of ship waves were measured continuously over a four week period in summer 2008, offshore from a semi-sheltered beach located ~2700 m from the sailing line. During calm conditions, vessel generated nonbroken waves of up to 1.5 m, with periods of 10–13 seconds were measured in the nearshore. The typical daily highest ship wave is approximately 1.2–1.3 m. Frequent, intense wake-waves add significantly to the total wave energy experienced on several sections of the coastline and may have a significant effect on the morphology and the sediment dynamics on medium-energy beaches, in particular, because of the difference between the wake propagation direction and that of the dominant wind waves. The potential of ship wakes to alter the natural beach processes is demonstrated based on observations of a semi-sheltered beach on the Island of Aegna, that receives substantial ship wave energy. Beach profiles were measured up to several times a day for more than 20 days. An adjacent jetty restricts sediment transport from the east. Overnight and during high-energy wave conditions, wind generated waves build the beach adjacent to the jetty. During calm periods the beach is not replenished and significant loss of sediment across the beach profile is evident, due to ship wakes. The beach, therefore, never reaches an equilibrium shape, as might normally be expected on the up-drift side of a groin. Instead, the area offshore adjacent to the jetty serves as a sink for the beach sediments.

Item ID: 5570
Item Type: Conference Item (Research - E1)
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Date Deposited: 12 Nov 2009 23:01
FoR Codes: 09 ENGINEERING > 0911 Maritime Engineering > 091104 Ship and Platform Hydrodynamics @ 50%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040601 Geomorphology and Regolith and Landscape Evolution @ 50%
SEO Codes: 88 TRANSPORT > 8802 Water Transport > 880204 Passenger Water Transport @ 40%
88 TRANSPORT > 8898 Environmentally Sustainable Transport > 889899 Environmentally Sustainable Transport not elsewhere classified @ 30%
96 ENVIRONMENT > 9609 Land and Water Management > 960902 Coastal and Estuarine Land Management @ 30%
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