Marine Link
Monday, September 26, 2016

A World’s First in Underwater Repair:

January 6, 2012

The insertion of a complete, prefabricated replacement hull section in a badly damaged ship at anchor. 
 
 

On Friday 22nd July, 2011 the Tsavliris Salvage Group urgently dispatched salvage tug Stevns Battler in response to a call for assistance from bulk carrier Navios Sagittarius (GRT: 38,849, DWT: 75,756), laden with 73,419 metric tons of iron ore pellets. The Sagittarius had run aground on the Tonneberg Banke, about 23.5 miles east of Frederikshavn, Denmark, while on passage from Finland to China. The salvage team arrived the same day and prepared a refloating/salvage plan, incorporating environmental and safety measures. On July 26th, a salvage plan was approved by the Danish authorities and on July 28th, after about 3,000 tons of cargo had been transferred to the lightering vessel, by pressurizing certain tanks and with the assistance of tugs, the Sagittarius was refloated.

 

On the 23rd of July, a Hydrex diving team contracted by the salvors had carried out a preliminary video inspection which found large penetrations, indentations and cracks in the hull, and heavily deformed plates. However, it was impossible to get a full picture of the damage with the ship still aground. The vessel was then towed to Frederikshaven for a detailed underwater inspection, extensive bottom repairs, and reloading of cargo.

Detailed inspection


With the Sagittarius refloated it was possible to carry out a detailed inspection of the hull and note all damage. Tsavliris had signed a Lloyd’s Open Form salvage contract with Navios and subcontracted several companies to carry out inspection and repairs. The chief subcontracting company for the inspection, planning and repair work was Hydrex. Tsavliris had previously contracted Hydrex to carry out a stern tube replacement on the bulk carrier Minoan Euro in Manila. Captain George Polychroniou, Tsavliris’ Operations Manager overall in charge of both salvage projects confirmed that, “The cooperation with Hydrex was excellent in both operations.” This was particularly important in a complex salvage operation which lasted three months and for which Hydrex mobilized 24 divers full time, in two shifts, for the duration of the operation, under the technical directions of Tsavliris naval architects and salvage master. The Hydrex team of 24 full-time divers was organized and assembled by Onno De Nooijer, Technical Services Officer for Hydrex in Antwerp, Captain Barend Visser, Tsavliris Salvage Master and Michalis Chourdakis, Tsavliris Technical Consultant, and headed up initially by Toon Joos, one of Hydrex’s most experienced diver/welders, who was able to provide much technical input and assistance to the naval architects during the planning stages. Toon was later replaced by Jan Botte who successfully led the Hydrex divers for the majority of the repair operation.

 

Thus it was Hydrex divers who examined the hull, took measurements and photographed and videoed the damage. They reported two very large holes in the hull, one about 5 x 5 meters aft on the port side and the other about 8 x 1.8 meters near the forepeak on the port side, as well as many smaller holes, cracks and indentations. The damage was very severe indeed.
 



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