The Marine Accident Investigation Branch (MAIB) has released its report covering the sinking of 24m, privately owned motoryacht Isamar, which struck the Grand écueil d’Olmeto shoal while on passage from Bonifacio, Corsica to Roccapina bay on 17 August 2013. The three crew on board were unable to halt the flooding, but were able to abandon the vessel with the eight passengers before Isamar foundered in 55 metres of water.

Isamar. Credit: MAIB

The report reveals that Isamar left Bonifacio in calm seas and good visibility, and because of this the master decided not to switch on the radar. “The master navigated by eye and monitored the vessel’s passage on an Electronic Chart System (ECS), which was set on a 6-mile scale," the report states. "The vessel had no paper charts on board, and the master relied on the ECS to identify land masses and seabed topography. The ECS’s electronic charts had not been updated for nearly 10 years. Although the echo sounder was switched on, its shallow water alarm had not been set.” Further to this, the report mentions that no waypoints or course lines were set on the ECS.

“At about 1730 Isamar lurched suddenly,” the MAIB report continues. “This was followed by violent vibrations and the sounding of the high level bilge alarms for the engine room and lazarette. The mate looked behind the vessel and saw an underwater reef through the clear sea. The master immediately disengaged Isamar’s engines and rushed towards the engine room, which was entered through the lazarette. On descending into the lazarette, he found himself thigh deep in water. He passed through the watertight bulkhead door into the engine room, where he found about 0.5m depth of water. He started two bilge pumps and, in an attempt to ensure their efficiency, led a flexible 75mm suction hose from the pump suction chest, directly into the lazarette through the open watertight door.

"Had the watertight door been closed and the pumps set to pump out the engine room, the vessel would have stayed afloat longer and might have been saved.”

"While the master was below decks, the mate mustered the passengers and instructed them to don their lifejackets. He then checked the vessel’s position on the ECS and noted that the display was on quite a large scale. By pushing the scale adjustment button four or five times, he reduced the scale to its minimum setting on 0.5 mile. At this scale, the ECS did show an area of shoal water not apparent on the larger scale. However, it did not display any depth soundings as shown on official hydrographic charts.”

Upon returning to the bridge, the master transmitted a ‘Pan-pan’ urgency message by radio, which was heard by both the coastguard and vessels in the area. Isamar settled by the stern and a nearby sailing yacht came to assist. A lifeboat later arrived on scene, but by this time it was apparent that Isamar was beyond saving and that any attempt to put men on board would be hazardous. Isamar finally sank in 55 metres of water about three hours later.

Intended route of Isamar on official chart. Credit: MAIB

The MAIB report followed up its narrative by drawing several conclusions from the incident that should be noted by the industry to avoid similar situations taking place. “Isamar’s master relied on an ECS with electronic charts that were set to the wrong scale, unsuitable for the intended voyage and out of date as the primary means of navigation,” the MAIB report considers. “Had appropriate, updated charts been available on board, Isamar’s master could have prepared a passage plan which would have enabled him to ensure that the intended route was suitable for Isamar’s draught.

The standard marine emergency procedure of isolating damaged areas by closing watertight doors were not applied, allowing the vessel to flood and sink faster than would have been the case had the watertight openings been closed. Flooding was not contained by closing the watertight door between the lazarette and the engine room, and pumping capability was not used to best effect. Had the watertight door been closed and the pumps set to pump out the engine room, the vessel would have stayed afloat longer and might have been saved.”

The full report on the incident can be read here.