One passenger sustained head injuries when the RIB, with a helmsman and three passengers on board, collided with the centre support polars of the Athlone Railway Bridge, close to the Westmeath town's marina, on the evening of 14 July 2012.
Though the injured passenger required a transfer to Beaumont Hospital in Dublin after losing consciousness, all four people on the RIB were later released from hospital.
The RIB itself, however, was damaged beyond repair, says the Marine Casualty Investigation Board (MCIB) report into the incident, which also detailed that the nature of the damage caused was consistent with a RIB accelerating at a speed greater than 15 knots.
This was in spite of speed limits of the Shannon Navigation set at no more than 5kmph within 200m of any bridge, quay, jetty or wharf, when in a harbour area or within 100 of any moored vessel.
It was also determined that was the collision occurred around sunset, "it is likely that the light conditions would not have been good".
The full MCIB report into the Lough Ree incident is available to download below.