traffic separation schemes

traffic separation schemes, areas designated by the International Maritime Organization (IMO), and authorized by the International Convention for the Safety of Life at Sea, or SOLAS, for separating marine traffic where it converges. Their purpose is to reduce traffic density, and usually lessen the incidence of encounters between ships on reciprocal or nearly reciprocal courses, which are the most dangerous kind. In 1963 the Institutes of Navigation in Great Britain and France with the Deutsche Gesellschaft für Ortung und Navigation issued a report on traffic regulation in the Dover Strait which in the following year was accepted by the Inter-governmental Maritime Consultative Organization (now IMO).

The situation as it appeared to the Dover Strait Working Group at the time was that, in an area bounded by the Elbe and the English Channel where almost half the collisions in the world then took place, and through which something like 750 ships passed each day (a somewhat inflated figure as it turns out based on port returns), almost all the traffic used a passage barely 5 nautical miles wide between the Varne Bank and the English coast, irrespective of which way it was going. The report proposed a voluntary separation of the through traffic by the Varne Bank, the observance of which would be governed by the Ordinary Practice of Seamen as envisaged in Rule 29 of the International Regulations for Preventing Collisions at Sea, or Colregs.

A further report from the same three institutes entitled ‘The Separation of Traffic at Sea’ proposed measures to enable ships to navigate through heavily congested areas with more efficiency and greater safety, and in due course this was accepted by the IMO. It outlined the principles of routeing which now form the basis of traffic separation schemes throughout the world. In 1967 the first traffic separation scheme in international waters was implemented in the Dover Strait and its adjacent waters. Within the next few years some 50 other separation schemes were adopted, mainly in north-west Europe and the USA. Today some hundred separation schemes have been adopted by the IMO and over two hundred, some imposed by governments within their territorial waters, appear on official charts. In 1977 revised Collision Regulations came into force and it became mandatory to comply with the new Rule 10 which deals with the observance of traffic separation schemes.

The high incidence of collisions between vessels going in opposite directions has now been largely eliminated and there has been a substantial reduction of collisions worldwide since the introduction of traffic separation schemes.

Mike Richey