Koole Contractors has added a new semi-submersible heavy-lift vessel to its fleet and is towing it to Gibraltar to support a major wreck removal project
After almost three months of maintenance, class inspections and mobilisations in Rotterdam, the Netherlands, this heavy-lift barge with accommodation, Fjord, is en route to Gibraltar, towed by Koole’s 2011-built anchor-handling tug Norne.
This convoy is expected to arrive 26 March, ready to assist in the removal of the wreck of OS 35 bulk carrier outside of Gibraltar.
Its arrival will be timely as Koole Contractors has to complete this wreck removal project by the end of May and the wreck has been damaged by storms. The plan is for the sunken ship to be cut in two at a point which avoids the oil tanks. The bow will be hoisted using chains, while the stern will be refloated.
Both sections will be placed on semi-submersible vessel Fjord and shipped to an EU-approved recycling facility.
The Port of Gibraltar and Koole Contractors are confident this plan is deliverable by 30 May, and fully compatible with the strictest of measures for the protection of the environment.
In the latest report on the wreck, the captain of the Port of Gibraltar reported damage to both the accommodation block and hull following adverse weather and sea conditions. OS 35 has sustained structural damage, most visibly to the starboard side of the accommodation block and hull, but it is not considered too extensive and debris from this is contained within the site of the wreck.
The original crack in the hull has extended to the port side, and the two parts of the ship are now only tenuously held together by the bilge keel. Shifting sands and heavy swells mean the bow is now sitting a further 4 m into the sandy seabed, while the stern is sitting a further 2 m into the seabed. However, OS 35 has not moved from its original site, according to the latest port captain’s report.
This demonstrates the effectiveness of the strategy to stabilise the vessel with a controlled sinking, which provided the wreck with the maximum possible stability to weather the expected winter storms.
Damage to the hull has enabled divers to conduct visual inspections of fuel Tank 1. They confirmed all four tanks that make up Tank 1 have suffered damage and any light sheening from fuel oil discharges are being contained within the boom. The other set of fuel tanks remain undamaged and are situated in the aft area of the wreck, which has not suffered much damage. The dive survey has confirmed with certainty these tanks are intact and are not at risk of failing and causing a sudden release of residues.
Salvors have been removing the cargo from OS 35 at a rate of 600-900 tonnes per day, and damage caused by the storms has had no detrimental impact on the cargo removal operations or their timelines.
The current condition of the wreck and the damage to its hull and structure means plans for its final removal may need to be tweaked, although it is unclear as to how this may affect the projected timelines, if at all.
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