IMO issues a circular for routeing measures other than traffic separation schemes

The International Maritime Organization has issued the circular regarding routeing measures other than traffic separation schemes.

This circular has been issued on November 28th, 2022.

Routeing measures other than traffic separation schemes

The Maritime Safety Committee, at its 106th session (2 to 11 November 2022), having considered the recommendation made by the Sub-Committee on Navigation, Communications and Search and Rescue at its ninth session (21 to 30 June 2022), and in accordance with the Procedure for the adoption and amendment of traffic separation schemes, routeing measures other than traffic separation schemes, including designation and substitution of archipelagic sea lanes, and ship reporting systems (resolution A.858(20)), adopted routeing measures other than traffic separation schemes, as follows:

1. recommended route Off the coast of Shio-no-Misaki;
2. amendments to areas to be avoided Off the California coast (resolution A.711(17));
3. no anchoring area In the southern portion of Pulley Ridge; and
4. recommendation on navigation for containerships in the traffic separation schemes Off Vlieland, Vlieland North and Vlieland Junction, Terschelling-German Bight, Off Friesland and German Bight western approach,

as set out in annexes 1 to 4, respectively.

Annex 1: Recommended route "Off the coast of Shio-no-Misaki"

(Reference chart: JP93, 2007 edition. Note: These charts are issued by the Japanese Coast Guard and based on  World Geodetic System 1984 datum (WGS 84).)

Description of the recommended route

Masters of ships in transit should be aware of the concentrated traffic close to the Shionomisaki Lighthouse and consider avoiding the area.

Should they decide to navigate within 3.5 nautical miles south of the Shionomisaki Lighthouse, they are advised to follow the recommended route with the corresponding direction of traffic flow, with a central line between the following geographical positions:

(1) 33°24.3' N 135°45.3' E (2.0 nautical miles 180 degrees from Shionomisaki Lighthouse); and

(2) 33°25.9' N 135°52.5' E (2.5  nautical miles 165 degrees from Kashinosaki Lighthouse).

In  addition, the following geographical position is depicted to clearly indicate that the recommended route is established landward:

(3) 33° 22.7' N 135° 45.3' E (3.5 nautical miles 180 degrees from Shionomisaki Lighthouse).

Note 1: Ships not intending to use the recommended route should navigate further south of 3.5 nautical miles from the Shionomisaki Lighthouse.

Note 2: Two virtual AIS-AtoNs are deployed at positions (1) and (2) above to mark the centre line of the recommended route and another at position (3) to indicate the point north of which the recommended route is established.

Annex 2: Amendments to areas to be avoided "Off the California coast"

Off the California coast

(Reference charts: United States 18700, 2013 edition; 18720, 2020 edition; 18721, 2009 edition. Note: These charts are based on North American 1983 datum.)

Description of the area to be avoided

(a) In the region of San Miguel, Santa Rosa, Santa Cruz and Anacapa Islands off the coast of southern California

The existing area to be avoided is replaced by the area bounded by a line connecting the following geographical positions:

(1)  34°27'.23 N, 121°07'.57 W
(2)  34°02'.01 N, 119°16'.56 W
(3)  33°59'.77 N, 119°11'.85 W
(4)  33°54'.01 N, 119°16'.87 W
(5)  33°46'.03 N, 120°09'.56 W
(6)  33°49'.02 N, 120°54'.39 W
(7)  34°14'.04 N, 121°11'.90 W

Annex 3: No anchoring area "In the southern portion of Pulley Ridge"

(Reference chart: United States US2GC09M, edition 25.0 of February 2022. Note: This chart is based on North American 1983 datum.)

Description of the no anchoring area

A no anchoring area for all ships is established in the area bounded by a line connecting the following geographical positions:

(1) 24° 52'.87 N, 83° 41'.85 W
(2) 24° 58'.30 N, 83° 38'.55 W
(3) 24° 58'.30 N, 83° 37'.00 W
(4) 24° 41'.12 N, 83° 36'.91 W
(5) 24° 39'.67 N, 83° 42'.65 W
(6) 24° 47'.55 N, 83° 55'.24 W
(7) 24° 57'.06 N, 83° 48'.41 W

Annex 4: Recommendation on navigation for containerships in the traffic separation schemes "Off Vlieland", "Vlieland North and Vlieland Junction", "Terschelling-German Bight", "Off Friesland" and "German Bight western approach"

1. Masters of containerships, when planning their passage through the waters north of the Wadden Islands, either eastbound or westbound, and making use of the traffic separation schemes (TSSs) located in this area, should be aware of the risk of loss of containers to the sea under unfavourable weather conditions.  

This risk becomes particularly imminent during heavy sea conditions and high waves from a north to north-west direction.

2. The most probable phenomena leading to the loss of containers are extreme ship motions and accelerations due to roll resonance, ship contact with the sea bottom, impulsive loading on containers due to green water* and slamming-induced impulsive loading on the hull.

In this respect, masters should ensure that there is an adequate under-keel clearance at any time of the passage.

*Green watermeans a large quantity of wateron a ship'sdeck as a result of massive waves, typically during a storm.

3. In particular, the following classes of containerships risk losing containers to the sea under the following unfavourable circumstances:

• containerships with a length between 100 and 200 metres when predicted significant wave heights exceed 3.3 metres. Masters of these ships are recommended to take appropriate measures and alter course and/or speed if necessary,  to avoid the mentioned phenomena in paragraph 2 (typically occurring when coming transverse to the wave direction); and
• containerships with a length of 200 metres or more, or with a beam of 32 metres or more, when predicted significant wave heights exceed 4.5 metres. These ships are recommended to take the northern route (i.e. the TSS East Friesland and TSS German Bight western approach) in order to retain an adequate under-keel clearance and avoid bottom contact, and take appropriate measures and alter course and/or speed if necessary, to avoid the mentioned phenomena in paragraph 2 (typically occurring when coming transverse to the wave direction).

4. In order to mitigate the risk of loss of containers to the sea, the German Federal Waterways and Shipping Administration and the Netherlands Coastguard have established similar warnings or advice transmitted via NAVTEX and/or calling ships by VHF. Predictions of wave heights in the area are also transmitted via NAVTEX.

RELEVANT DOCUMENTS (AVAILABLE ONLY TO SUBSCRIBERS):

Routeing Measures Other Than Traffic Separation Schemes

Ships' Routeing