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The International Maritime Organization (IMO) has decided to establish a new routeing system in Kattegat and the northern part of The Sound from 1 July 2020.

The intention is to reduce the large number of ships in the existing Route T by establishing a new recommended route, Route S, along the Swedish coast from Læsø Island to The Sound. Along Route S, three traffic separation schemes will be established in order to separate north- and southbound traffic. Vessels to and from The Sound shall use Route S and vessels to and from the Great Belt shall use Route T. The existing Route T will change slightly when the new routeing system comes into force.

What are the consequences?

Along the Swedish coast
These changes will result in an increase in the number of merchant ships along the Swedish coast, east of Fladen and Lilla Middelgrund. The number of merchant ships in the area close to Kullen will therefore also increase.

Between Læsø Island and Tistlarna light
A precautionary area will be established northeast of Læsø Island where Route T and Route S will join. In this area, northbound vessels will approach from both Route T and Route S and proceed into the northern part of Route T. The southbound traffic will be split as some vessels proceed in Route T and others use Route S.

Which rules apply for traffic separation schemes (TSS)?

The International Regulations for Preventing Collisions at Sea (COLREG), most specifically Rule 10, apply to the water in and around a traffic separation scheme. In short, Rule 10 states:
- A vessel shall proceed in the appropriate traffic lane in the general direction of traffic flow for that lane.
- A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.
- A vessel navigating in areas near the terminations of traffic separation schemes shall do so with particular caution.
- A vessel of less than 20 metres in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane.

Where can I find more information?

Detailed information will be published in Notice to Mariners during the first half of 2020. Additional information will be published throughout 2020 on this website.

When will updated charts be available?

New editions of the affected charts will be available from April-May 2020. A new edition of the small craft chart Västkusten Södra is planned for spring 2021.


Inshore traffic zone: A designated area between a traffic lane and the coast. Inshore traffic zones may be used by vessels with a length less than 20 meters.
Notice to Mariners: The official publication for corrections of navigational charts.
Precautionary area: An area where a vessel must navigate with particular caution.
Recommended route: A suggested route for vessels in transit.
Routeing system: A system of routeing measures, for example recommended routes and traffic separation schemes, aimed at reducing the risk of casualties.
Traffic separation scheme: An area where opposing streams of traffic are separated into different traffic lanes.

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