As previously reported on Afloat.ie, David Warnock and Daryl Burke died after the borrowed boat in which they were travelling with John Trimble overturned in Lough Ree outside Athlone on the afternoon of 20 March 2014.
Trimble, the only survivor, was released from hospital five days after the incident, but Warnock died in hospital later that day, and Burke's body was not recovered till two weeks later on 5 April.
MCIB investigators found that the trio had dismissed warnings about changeable weather by a local man while preparing to return to Hodson Bay after their day's angling.
Upon his rescue, Trimble described how the boat began to get lower in the water, and when the three men on board moved to the centre to bring it to an even keel, it suddenly went down by its stern, throwing them into the water.
Subsequent investigations of the boat, once recovered from the lake, found that significant parts were in poor condition, with a number of drain holes missing bungs, and several holes in the transom big enough to allow as much as 3 litres of water per minute into the boat's void spaces.
"It is probable that the rate of flooding would have increased the longer the boat was in the water as the flooding was causing the vessel to lose freeboard and in turn, immerse more holes," according to the report. "The low freeboard, combined with the spray and waves caused by the wind gusts of 35 knots, would also have led to the vessel shipping water over the gunwales."
Additionally, investigators found there were only two PDFs on board for the three passengers, and no other safety equipment which might have alerted rescue services to arrive sooner.
The MCIB's full report on the incident is available as a PDF to read or download HERE.