Octopus Harald - Marine Accident Investigation Branch

Figure 5Octopus agroundOctopus refloated 40 minutes after the grounding, and was returned to Hatston Pier inKirkwall where all four legs were found to be damaged. The damage to the barge costan estimated £1m to repair. The delay in returning Octopus to Seal Skerry Bay alsoresulted in extensive delays to the project when the seabed frame, constructed duringthe initial installation stage, collapsed in the strong tides.Following the grounding, the UKHO initiated NAVTEX warnings of the shoal danger inthe area. A week after the grounding, the Orkney Harbour Authority pilot boat carriedout a survey of the area, which confirmed the presence of an uncharted shoal area witha minimum depth of less than 8m, the bank covering an area of approximately 2.5 x 2.5cables.The MCA, UKHO and the Shetland Coastguard were advised of the survey’s findings,and the area of the grounding was subsequently re-surveyed by the MCA’s EmergencyTowing Vessel (ETV) Anglian Sovereign. The more accurate survey data obtainedduring this survey was used to generate the chart correction data issued in AdmiraltyNotices to Mariners (NTM) Week 41, published on the UKHO Web site on 5 October2006 and in paper format on 12 October 2006. The revised charted depth in thelocation of the grounding was shown in the NTM as 7.1m (Figure 6).7