Three fishermen feared drowned off Dorset coast A coastguard helicopter and three navy ships have joined the search for the 50-year-old wooden boat, the Purbeck Isle. Three fishermen are missing, feared drowned, after their boat vanished without trace in the Channel. The 50-year-old wooden vessel, the Purbeck Isle, disappeared in choppy seas off Portland Bill, Dorset. A major air and sea search was launched involving three navy ships and the coastguard helicopter, but they could find no trace of the boat or of wreckage. The skipper is believed to be an experienced fisherman in his 30s, while the crew are both in their 20s. One has been identified as Robert Prowse, 22, a father of three. His mother, Maxine Prowse, said: "I'm just listening to the news now and waiting. He's a hard-working lad. He has a lot of friends. Coastguards are examining a sonar image of an object on the seabed 55 metres (180ft) down taken by a survey ship. A spokesman, Fred Caygill, said: "What we have is an image from 55 metres down, but it can't be clearly identified. We had a survey ship in the area with a sonar and it scanned the seabed. It did give us an image from about 10 miles south of Portland Bill, but it is impossible to decipher. According to locals the crew had been potting for whelks. Ron Brown, a local skipper, highlighted the dangers, saying: "If you are pulling in pots and one gets stuck it can pull the boat down and then if a wave hits you and everyone is on deck there might not be time to raise the alarm." Dave Pitman, another skipper, said: "They were working with whelking pots as I understand it. They were moving the gear from one place to another, which is a normal operation. We just all hope they are safe. Andy Alcock, the secretary of the Weymouth and Portland Fishermen and Licensed Boatmen Association, said: "There was a life raft on board and there is a chance the men are in that and have been blown up and down the Channel and are awaiting rescue." The alarm was raised late on Thursday afternoon when the 11-metre (36ft) boat failed to return to port in Weymouth. By that time there had been no word from the fisherman for nine hours since they left the harbour at 8.30am. Coastguards repeatedly tried to contact the crew by radio but were met with silence. Two British naval vessels including the type 42 destroyer HMS York and an US navy supply vessel joined the search. A coastguard helicopter searched the Purbeck Isle's regular fishing grounds, up to 10 miles off Portland. Caygill said on Friday: "The boat went out yesterday morning and was seen leaving the harbour at 8.30am. We received a call at 5.40pm from a fisherman who was concerned about the Purbeck Isle. We commenced a major air and sea search for the Purbeck Isle but with no specific location we went over its usual fishing grounds. We are in touch with the men's families and the police. We obviously live in hope of finding the men and we will continue with this search and keep going for the best part of today.