Cape Town - Nearly four months after contact was lost with the three-man South African crew of a catamaran in the Indian Ocean, an upturned catamaran has been sighted in the Indian Ocean.Jared Blows, spokesperson for the Maritime Rescue Coordination Centre (MRCC) in Cape Town, said on Monday that a cargo vessel had sighted the upturned hull about 1 078km east of Mauritius.He said it could not be said with 100% certainty that the hull sighted by the cargo vessel was that of the missing catamaran Sunsail RC044-978, which set out from Cape Town for a delivery trip to Phuket, Thailand, on December 14.The crew of the Sunsail - Anthony Murray, Reg Robertson and Jaryd Payne – was last heard from on January 18.Blows said the upturned hull was spotted late on Thursday and, like the Sunsail, had a blue hull.“We were sent photos, but we can’t say for sure that it is the boat. They [the photos] aren’t very clear and were taken from some distance,” he said.Blows said that the MRCC had called off the search and rescue, but would continue to provide information to the families of the crew.Salvage operation“It is now a salvage operation, but we cannot get involved in that. We are still assisting locating the vessel.”He said that a navigational warning had been sent to ships by the South African maritime authorities and the Indian maritime authorities.Diane Coetzer, Murray's sister-in-law, said: “The families are all very distressed at this sighting. There has potentially been a loss of life and there needs to be an investigation.”The delivery was for US-based world maritime leisure business Tui Marine.The families of the four men reported the failure of the crew to arrive at their destination on February 12.Skipper Murray, 58, was reported to have over 25 years experience at sea, including multiple international catamaran and yacht deliveries while 59-year old Robertson is also reported to be an experienced yachtsman and a member of the Royal Natal Yacht Club. Payne was 20 years old at the time of the Catamaran’s disappearance.Emergency beaconThe yacht's Emergency Position Indicating Radio Beacon (EPIRB) was never activated.If a signal from the EPIRB is detected then search and rescue will be activated, the extent of which is dependent on the resources available in the area at the time.Blows said the sighting of the upturned hull was well within the area which it was believed the Sunsail had gone missing.