Over the last month Hydrex diver-technician teams have carried out several in-situ insert and doubler plate repairs across Europe. While these repairs may not entail a very large mobilisation, they are nevertheless very important in keeping a vessel on schedule without unnecessary loss of time or money.
The following article focuses on three of these operations, starting with a bilge plating repair on the port side of a 230-metre container vessel berthed in Rotterdam.
An inspection performed by Hydrex divers shortly after arriving at the location revealed that an earlier installed temporary doubler plate measuring 700 x 700mm was covering the damage on the outer shell plating. While it was being removed, a cofferdam was adjusted to the size of the affected area and subsequently installed. Next a frame was cut away to enable the team to remove the damaged bilge plating and to fit the new insert plate (measuring 480 mm x 690 mm). The insert was then welded with full penetration welding and approved by an ultrasonic testing operator. The permanent repair was carried out in accordance with Germanischer Lloyd's and will require no further care.
Shell plating repair in Flushing
Hydrex was contacted to install a doubler plate over a corroded hole located under the sounding pipe in the bilge tank of a 200-metre general cargo vessel. After the exact location of the hole had been pinpointed on the outside of the hull, a cofferdam was installed over it. The corroded area was then cleaned from the inside of the vessel and filled with clad welding. A doubler plate measuring 300 x 300 mm was then installed over the area to prevent the damage from reoccurring.
Thanks to this underwater repair the owner has the opportunity to plan in permanent repairs at a more convenient time during the next scheduled docking instead of having to take his vessel into drydock immediately.
Double bottom plate repair on bulker in Brixham
A 225-metre bulker had suffered a large crack in its double bottom plate and a repair was scheduled during the vessel's stop in Brixham, United Kingdom. The damage found required a 300 x 550 mm insert.
The operation started with the removal of a 2,200mm area of the bilge keel and a 1,700 square millimetre area of the doubler plate underneath. This was done to enable the installation of the cofferdam on the underwater hull of the vessel.
Next the operation continued on the inside of the vessel. The area around the crack was cut away and the insert was installed and welded into place. Its integrity was verified by ultrasonic testing and authorised by the class. This allowed the owner to sail his vessel again, permanently repaired.
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