Octopus Harald - Marine Accident Investigation Branch

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2.4.5 Decision to divert west of Little Green Holm IslandThe minimum depths expected once clear of the port of Kirkwall were in excess of 20m,and the tow master’s decision to increase the draught of Octopus from 5m to 13m toincrease stability, reduce rolling, and save time at the destination, was based on thecharted information available and the advice of the tug skipper.The subsequent choice of routing to the west of Little Green Holm Island was madedue to the strength of tide being experienced on passage. Routes both east and westof Little Green Holm had been evaluated prior to the voyage, and both options wereconsidered to be acceptable, with the final decision being made on the tide and swellconditions encountered during the voyage.2.4.6 The method statementThe method statement did not identify the maximum permitted draught for the voyage,and the depth at which the legs were extended was left to the discretion of the towmasters and tug skippers. In using the routes either side of the Green Holm Islands, theplan did not take into account the limitations of the chart in use, and did not questionthe local tug skipper’s knowledge of operating deep draught vessels in the area. Duringthe planning stages, the option to pass to the west of little Green Holm Island did notacknowledge that this route was primarily used by shallow draught vessels, whereasthe route to the east had been tested by deeper draught vessels via the Falls ofWarness.As the hazard of incorrect charted depth had not been identified, the options outlined at2.4.2 were not considered.2.5 STANDARD OF UK SURVEY2.5.1 Orkney Islands Survey StandardMuch of the area in the Orkney Islands is surveyed to 19 th Century standards withleadline surveys still prevalent in the area. The area in the Falls of Warness wherethe grounding occurred was last surveyed more than 150 years ago. As MCA budgetsallow, the area is surveyed to modern standards. Surveying the waters to the east ofthe Islands was progressed in 2006, as was the area to the north of the grounding.However, this survey stopped 200m short of the shoal patch. The surveys had led tonumerous depth alterations and changes, although none of these corrections were ofthe same magnitude as the reduction in depth from 26m to 7.1m.That the UKHO was not aware of the shoal patch in the area was primarily due to thelack of hydrographic survey. However, the area was frequently transited by vesselsfitted with echo sounders and some of these could have been aware of the shoal patch.Also, the area to the south of the Green Holm Islands was infrequently used by localfishermen, and they might have been aware of its presence. While a depth of 7mmight be of little concern to the local user, it could have been catastrophic to a cruisevessel or tanker of sufficient draft. Had any of the local traffic reported the possibleexistence of an uncharted shoal in the area, either by Hydrographic Note or to the localCoastguard, earlier action could have been taken to accurately survey the hazard.26
2.5.2 MCA survey progressThe CHP budget in 1982 was around £5m. The 2003 IHMC report recommended, asa high priority, the doubling of the CHP budget to attempt to improve the rate at which19 th Century surveyed areas would be resurveyed to modern standards, yet in 2006the MCA’s budget for hydrographic survey was still only £5.4m.Since the setting of the budget for the CHP of around £5m in 1982, the real value ofthis figure has reduced considerably over the intervening period. While savings havebeen achieved by the use of modern survey methods and by the use of contractedsurveying in lieu of RN assets, the static budget still represents a significant reductionin funding over time.Although the IHMC’s 2003 report was tabled and accepted at the annual meeting of theCHRC in January 2004, no subsequent request for additional funding has been madeto DfT.Further, at the time of this investigation, work had still to start on the MCA’s new riskmatrix for identifying survey priority, by combining AIS data with survey source data.2.6 ELECTRONIC CHART INFORMATIONProgress in transferring chart survey source data into CATZOC for use with electroniccharts is being progressed worldwide as resources allow. At this early stage in theprocess, while the definitions of CATZOC are in the Mariners Handbook, and the datais available to ECDIS users, the industry’s understanding of the system appears limited.While the modern British Admiralty metric-style colour charts might give a misleadingimpression of their accuracy to inexperienced mariners, the current system ofdisplaying source data, with its associated warnings, does ensure the information canbe read by those who know what they are looking for. Of more concern is that manyelectronic navigation and charting systems using vector chart presentations, eitherdo not display source data at all, or contain the information in sub-menus. MAIB’sexperience from previous accidents is that the training of watchkeepers in the use ofECDIS and ECS systems is, at best, patchy and that many are only able to use thesystems’ most basic functions. Specific concerns include:• CATZOCs do not provide the navigator with the detail currently shown in the sourcedata diagrams on paper chart.• On ECDIS displays, CATZOC data is available, but has to be operator selected.Depending on the make/model of the ECDIS, this selection could be in any of thesub-menus.• ECS displays that use official electronic charts, are not always able to displayCATZOC information, even when it is available, and basic ECS systems that useunapproved charts may not display CATZOC at all. Numerous vessels now carryECS as a supplementary aid to their approved paper charts, but by default it hasbecome the primary method of navigation for some navigators.In this accident, Harald’s skipper was navigating using both paper charts and amonochrome electronic vector chart plotter with Seatrack software. The Seatracksoftware system was primarily aimed at the leisure market and did not displayCATZOC.27
Page 1 and 2: Report on the investigation of the
Page 3 and 4: CONTENTSGLOSSARY OF ABBREVIATIONS A
Page 5 and 6: IHMC - International Hydrographic M
Page 7 and 8: SYNOPSISThe jack-up barge Octopus w
Page 9 and 10: 1.2 PARTICULARS OF OCTOPUS AND ACCI
Page 11 and 12: 1.3.2 The voyageAt 1300 on 8 Septem
Page 13 and 14: Figure 5Octopus agroundOctopus refl
Page 16 and 17: Figure 7Admiralty Chart 2250 before
Page 18 and 19: Reproduced from Admiralty Chart 225
Page 20 and 21: Figure 10MCA Survey following groun
Page 22 and 23: 1.6.3 Category of Zone of Confidenc
Page 24 and 25: 1.7.3 ResearchIn 1997, the Departme
Page 26 and 27: 1.7.6 CHP survey effortAll survey w
Page 28 and 29: 1.8 INTERNATIONAL HYDROGRAPHIC ORGA
Page 30 and 31: SECTION 2 - ANALYSIS2.1 AIMThe purp
Page 34 and 35: 2.7 CRUISE SHIPS AND OTHER DEEP DRA
Page 36: SECTION 5 - RECOMMENDATIONS2007/165

Octopus Harald - Marine Accident Investigation Branch

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