One of the our good Owners / Manager requested in order to underwater repair the damaged echo-sounder while vessel was berthed alongside Algeciras port, TSE diving team proceed with a permanent afloat repair and install the new hat structure and fitted the new echo-sounder on the oil/chemical tanker vessel of 8500 DWT.
Close-up underwater cctv-video inspection together with Owners Superintendent and Class LR Surveyor representatives were taken in order to determine the damaged on the echo-sounder cover hat structure caused by impact scrapping.
The shell plating around the damaged area was found to be in an apparent good condition only affecting on the hat structure and subsequently on the echo-sounder navigation aid.
TSE diving team proceed to placing of one hand-made reinforced aluminium cofferdam of 700 mm lenght x 700 mm wide x 300 mm high x 10 mm thickness and 30 mm thick of rubber gasket foam provided with two inlet – outlet valves to cover securely the damaged cover hat. Divers secured the cofferdam to the bottom shell plating by means of wet-welding of a total 2 in number steel dogs together with steel wedges.
Following to the TSE approved procedure coded fitters and welders team cropped the damaged section in order to place the new approved hat cover structure.
After positioned the new echo-sounder structure, coded welders proceed to start with the SMAW first pass weld root full penetration welding (without backing strip). An independent NDT tester then carried out a dye-penetrant method to inspect the full penetration welding seam and proceeded to complete the welding permanent repairs. On completion of welding repairs, Ultrasonic method to inspect 100% of butts ´welds were carried out. No significant indications or anomalies were observed and was approved by LR Surveyor who was present during the operations.
Internal welding works were agreed by LR Surveyor and Owner´s Superintendent.
After finishing the internal permanent repair, divers removed the cofferdam and proceeded by close-up cctv-video system to inspected the full penetration weld seams and found agreed by LR Surveyor.
Divers proceeded to installing the new Echo-sounder. Also divers applied epoxy-cement around the weld seams to prevent corrosion.
The Echo-sounder replacement was concluded and confirmed approval of “permanent repairs” were satisfactorily concluded to a satisfaction of LR Surveyor and Owner´s Superintendent.