Octopus Harald - Marine Accident Investigation Branch

SECTION 3 – CONCLUSIONSThe following safety issues have been highlighted by this investigation. They are not listed inany order of priority.3.1 SAFETY ISSUES DIRECTLY CONTRIBUTING TO THE ACCIDENT WHICHHAVE RESULTED IN RECOMMENDATIONS• Melbourne Marine Services• The tug skipper and the tow master relied upon 19 th Century leadline surveyedcharts for the passage of a deep draught vessel outside of a recognised trafficroute. [2.4.1, 2.4.4]• The passage plan and execution underestimated the effect of tidal stream onthe tug and tow. [2.4.2, 2.4.6]• Surveys• Depths that are significantly less than charted might exist around the UKcoastline. The hazard of the bank was not identified as this was not charted.[2.4.2]3.2 SAFETY ISSUES IDENTIFIED DURING THE INVESTIGATION ALSOLEADING TO RECOMMENDATIONS• An increase in commercial activity, particularly of large cruise vessels, is noted inthe Orkney Islands. [2.4.4]• Electronic charts• The significance of CATZOC is not fully understood by many operators. [2.6]• The use of CATZOC is an ECDIS menu option and is therefore not immediatelyavailable to the navigator. [2.6]• CATZOC is unavailable on many unapproved ECS and chart plotters. [2.6]SECTION 4 - ACTION TAKENNone29