Re-routing of traffic via alternative navigation channels should only be considered if it is accepted that there is a very real problem with the current patterns in vessel movement and there is an alternative route available. This consideration is particularly important given the navigation and safety implications of re-routing. The practicality of re-routing traffic via alternative navigation channels will depend upon the location of a particular port or harbour and the geography of the surrounding area. In some cases additional dredging, at some cost and with potential environmental impacts, may be required to allow alternative routes to be used safely.

Examples where re-routing has been employed include Stena Line’s operation to Gothenburg Harbour (Hynds 1997). In response to growing concerns about ship wash and in an attempt to reduce any potential impact of its fast ‘water jet’ ferry operation on the Gothenburg archipelago, ferries were re-routed through the northern Torshamn Channel during the peak season when there is a considerable concentration of shipping within the channel to the north of Vinga. This response may have been appropriate in this situation, but consideration of such a step would need to be done (as in this case) in conjunction with operators and with a careful evaluation for any navigational and safety implications.

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