For the operations, a total of 5 crane barges or grab dredgers were chartered at ports on the coast of the Seto Inland Sea. This was because, as always, no vessels appropriate for oil recovery operations were available in the Japan Sea during winter, which is characterized by rough weather ( most of the work boats had been transferred to the Pacific side.)
The initially planned sweeping formation consisted of one vessel towing a guide boom and one crane barges recovering oil collected by the boom. However, the actual operations were carried out by a single crane barges, because the planned operational co-ordination between the 2 vessels was not possible or was difficult under the prevailing bad weather. It is estimated that a total of about 1,000kL of the mixture of spilled oil (85%) and sea water (15%) has been recovered.
b) Oil recovery vessels and equipment
The oil recovery vessel ASUWA of the Fukui Oil Storage Co., Ltd., registered in the Port of Fukui, was engaged in operations at sea from 9 January, 1997 when the rough weather temporarily ceased to dominate the area.
On 4 January, 1997, 5 days before these operations, the Maritime Safety Agency had already requested the dredger/oil recovery vessel SEIRYU MARU of the Ports and Harbours Bureau, Nagoya, Ministry of Transport, to proceed to the affected areas and commence oil recovery operations. The SEIRYU MARU actually commenced operations on 9 January.
The other vessels chartered for oil recovery operations include the TAKAHOKOMARU NO. 3 of Mutsu-Ogawahara Oil Storage Co., Ltd. and the HAKURYU of Shirashima Oil Storage Co., Ltd.
Vessels and equipment from overseas, which were dispatched in co-operation with the operations, included RO-SKIM system of EARL, Singapore, and oil recovery vessels from Russia carrying oil booms, oil trawl nets, DESMI 250 and FOXTAILS.
The oil recovery operations carried out by these vessels and equipment proved to be poor in terms of operational efficiency because of the high viscosity of the oil. They are assumed to have collected oil/water mixtures of about 1,100 kL (oil: about 100 kL). The RO-SKIM system failed to recover oil. The amounts of the oil/water mixture recovered by the Russian systems and equipment were about 430 kL of which about 200 kL were oil.
c) Others
Groups each comprising 2 small fishing vessels carrying recovery nets also participated in the operations. These vessels towed oil recovery nets and used dippers.
The oil recovery operations by these vessels covered large areas including Wakasa Bay, sea areas off Mikunicho (Fukui Prefecture), Kaga City. Kanazawa City, Noto Peninsula (each Ishikawa Prefecture), Toyama Prefecture and Niigata Prefecture, which were affected by the diffusing and drifting oils. Special measures were taken to prevent the oil from approaching the cooling water intakes of the nuclear power plants located on Wakasa Bay in Tsuruga City and in Shigacho, Ishikawa Prefecture.
(2) Recovery of oil drifting near the coast
The oil spilling from the bow and drifting oil slicks were driven ashore on the coasts of Ojima, Mikunicho, on which the bow ran aground on 7 January, 1997. The layers of oil near the coast lines passed under the Ojima Bridge and continued drifting southward toward Tojimbo. Oil booms were stretched along the bridge to prevent the oil from further diffusing and other items of oil recovery equipment were used.
a) Oil recovery equipment
2 types of recovery equipment, wear and disk types, as well as beach cleaners owned by the Petroleum Association of Japan were used. These items of equipment were used as oil transfer pumps between the beach and the drum cans/FASTANK, because oils subjected to cycled wave motions on the shoals tended to become highly viscose oil mass.
b) Vacuum cars and mobile concrete pumps
Vacuum cars were used for drawing oil directly from the coast and indirectly drawing oil from drum cans.
