The purpose of traffic separation schemes (TSS) at sea is to organize the traffic of vessels and improve safety of navigation. Vessels that decide to use TSS, have limited freedom of choosing a route. As early as back at sea they have to adjust their courses in order to enter the appropriate traffic line. This causes channeling of the shipping routes back at sea many miles before the TSS.
The introduction of a new TSS Slupska Bank by the maritime services without prior ordering to carry out detailed surveys of approach basins from the eastern and western sides by hydrographic services, has created a threat to the safety of navigation, especially for vessels with deep draught, exposing them to the risk of damage to the hull.
The State Commission for the Investigation of Marine Accidents considered reasonable issuing safety recommendations, forming the proposal of actions which may contribute to prevention of similar accidents like the one of the Twinkle Island, in future to the following bodies.
The Commission has recommended to carry out as soon as possible detailed multibeam hydrographic surveys using full sea floor search of the belt of water used for navigation by sea-going vessels from TSS Slupska Bank to the east towards the ports of the Gulf of Gdańsk. The Commission has recommended to intensify the activities associated with the initiative to appoint a new safe track of TSS Slupska Bank, to carry out appropriate surveys and to prepare relevant documents to be submitted to IMO.
The Commission has recommended to consider the possibility of determining and marking out on nautical charts a “recommended track with maximum recommended draught” – for vessels with deep draught going from the area of the Gulf of Gdańsk along the Polish coast in a westerly direction to the Danish Straits – from exit from the traffic separation schemes in the Gulf (e.g. from the latitude of φ = 54°45.0’N, after leaving the VTS Zatoka controlled area) to the TSS Slupska Bank and from the TSS Slupska Bank to the TSS Adlergrund, along the entire route or some (selected) sections of the route which had been checked in terms of bathymetric conditions.
The Commission has recommended to local units of the maritime administration, through the Port Captains of Gdańsk and Gdynia and shipping agents, to advise masters of vessels with deep draught, departing from these ports and heading for the Danish Straits, to use the assistance of sea pilots.
Moreover, the Commission has drawn the attention of the minister responsible for the maritime economy to determine with the Minister of National Defense the priorities in conducting surveys of the main shipping routes to Polish ports (including ports of the Gulf of Gdańsk and the external port in Świnoujście prepared for handling LNG, among others) and to increase the use of hydrographic units of the Polish Navy to carry out bathymetric surveys of Polish marine areas for the safety of navigation.
The Commission has recommended to apply to the United Kingdom Hydrographic Office to correct the Admiralty chart no 2369 and to remove the marking of wrecks in the vicinity of shallows of the depth of 14.2 m detected in June 2013 in the entrance area to the TSS Slupska Bank from the eastern side at a level of Stilo lighthouse.
The Commission has appreciated the initiative taken by the hydrographic service, after the accident of Twinkle Island, of active measures associated with surveying the depth on the shipping route from the ports of the Gulf of Gdańsk to the Danish Straits running to the south of the Slupska Bank, and in particular the fact of accomplishing the survey works to the west of the TSS Slupska Bank towards the traffic separation scheme TSS Adlergrund (east of Rügen). At the same time, the Commission has recommended to prepare, in cooperation with the maritime administration, a detailed plan of survey works, including a schedule specifying dates (months and years) and water basins where such works shall be conducted for the remaining water regions of the Republic of Poland. The activities carried out in accordance with such schedule would ensure the fulfilment of international obligations for Poland arising from the Copenhagen Declaration and would improve the safety of navigation in these areas.