SAFETY4SEA Focus - Q1 2018

Q1 2018 I issue 01 I SAFETY 4SEA 17 safety4sea.com ARTICLE ECDIS wrong settings The main cause of the grounding was the wrong parameters set on ECDIS. During voyage in this spe- cific area the safety depth was 7m (Safety depth = draught + squat + minimum UKC – height of tide). The safety contour set in the system was 5m. This created a false navigationable area for the bridge watch as no danger was alarmed through passage. Alarm Fatigue Warning of deviation from the planned route is achieved by use of the XTD setting, which is an opera- tor defined safety corridor either side of the planned route. For the leg of the passage plan at the time of grounding, the XTD settings were: XTD (port): 0.025nm (50 yards), XTD (starboard): 0.06nm (120 yards) The XTD alarm on board was active for 11 minutes when the ves- sel crossed outside the safety cor- ridor until the time of the grounding, but no one addressed it. Lessons to be learned 1. Plan correctly the passage. Use the appropriate param- eters on ECDIS for each sailing area. Remember that when- ever the safety depth changes (draught,squat,tide) the safety contour should be reconsidered. 2. All alarms to be addressed and considered. They are warnings that may save the vessel. The difference in navigationable waters with different safety contours is shown on images below. 2m Safety Contour (Credit: UK MAIB) 10m Safety Contour (Credit: UK MAIB) Note: This case study is edited from UK MAIB safety digest to highlight lessons learned from an ECDIS related accident.