Salvage tshd THOR R

In the early morning of 26 September 2004, the Danish trailing suction hopper dredger ’Thor R.’, owned by Danish dredging contractor Rohde Nielsen, collided with the construction vessel ’Ocean Ace’, while executing maintenance dredging in the navigation channel to the Port of Esbjerg. The next day the ’Thor R’ sank and subsequently capsized under water, partially impeding traffic into the port.

The contract for the salvage was awarded to the Dutch towage and salvage company Multrahip of Terneuzen, which immediately mobilized the 1500t floating sheerlegs ’Matador 3’. The sheerlegs owned by Bonn & Mees of Rotterdam and designed by Vuyk was collected in Rotterdam by the tug ’Multratug 7’.

Vuyk assisted on-site with engineering for preparation of parbuckling and lifting of the vessel.

The salvage of the vessel was complicated by strong tides, which allowed only four hours of diving time per day and by the soft sandy bottom, into which the wreck continually sank. The vessel was lifted on 24 October 2004 and subsequently transported into the port of Esbjerg by the sheerlegs and tugs. To place the dredger in Esbjerg’s local small dry dock (120 x 19.5 m) the sheerlegs had to re-rig the slings.

The ’Thor R.’ re-entered service after completing repairs with new Wärtsilä main engines.


Principal characteristics of the casualty  
Owner Rohde Nielsen
Flag state  Denmark
Built by  IHC Sliedrecht B.V., The Netherlands
Built 1984
Gross tonnage 1 995 GT
Deadweight 3420 ton
Hopper capacity 2 507 m3
Length overall  79.00 m
Breadth moulded
14.00 m
Depth moulded 6.30 m
Draft loaded 4.90 m
Totally installed power 3 622 kW

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