A rescue operation involving Gardaí and RNLI began after three men, who set off for Carnagh from Hodson Bay, fell into the water from a small fishing boat on Thursday afternoon.A man in the area raised the alarm at around 3.20pm after he witnessed the group in the 15-foot boat in windy conditions.Two men who were on the vessel were rescued by lifeboat crew and were taken to hospital in Ballinasloe, Co Galway.One man was retrieved semi-conscious from the water at 4pm and taken to shore to a waiting ambulance. The second man was found by the crew at 5.15pm and was also taken via ambulance for treatment.They are both reported to be in a critical condition.The RNLI lifeboat crew along with the Irish Coast Guard helicopter Rescue 118 and members of the Athlone Sub Aqua club and Lanesborough Sub Aqua Club were engaged in a full scale search for the third man until they were stood down due to fading light.The search is due to resume at first light on Friday.Commenting on the search, Lough Ree RNLI Lifeboat Operations Manager Damien Delaney said: "This was a major search and rescue operation on Lough Ree involving the RNLI, Coast Guard, Athlone Sub Aqua, Lanesborough Sub Aqua, and other local boats."The lifeboat crew were able to rescue two men from the water but a third remains missing."Our thoughts are with the men's families this evening. We will be launching again at first light to resume the search."