NAHANT – A U.S. Coast Guard helicopter spotted a small pleasure boat under the waves in Lynn Harbor late Thursday morning, according to Nahant Harbormaster Robert Tibbo.Tibbo said the small pleasure craft sank at its mooring off the state Department of Conservation and Recreation boat ramp, which is on the Lynn/Nahant line, sometime Wednesday during the winter storm that hit the area.Tibbo said the vessel was moored off the DCR boat ramp, but he has not been able to get in touch with the boat’s owners.Tibbo said he called in the Coast Guard helicopter to fly over the area late Thursday morning to help determine if the vessel had sunk.”I checked the area where the boat was moored and saw no indication a boat had actually sank. When boats sink you can usually tell where they are. There is usually a glaze on the water and stuff washed up on the beach,” he said.Tibbo said the U.S. Coast Guard did not see a sheen or any discharge on the water so he does not believe the boat poses a hazard to the environment.”We have no reason to believe anyone was aboard,” he said.Lynn Harbormaster Jim Perry said the boat belongs to a Nahant resident and it was towed from Seaport Landing to its mooring in Lynn Harbor last fall.”The owner has been maintaining the boat for several months,” Perry said. “It’s a small boat. If there was any oil or gasoline in it, it was very minimal. I think the owner will contact a commercial salvage company to bring the boat up.”Perry added he would not be surprised to find out the boat sank from the weight of snow and ice on board.The Coast Guard issued a public information notice informing boaters about that danger.Capt. Verne Gifford, who is the Commander of Coast Guard Sector Southeastern New England, said boats that are in the water are at risk in this weather.”Harbormasters, marina owners and operators and owners of recreational or small fishing boats still in the water should consider examining their boat for excess snow and ice,” Gifford said in a statement. “If safe to do so, they may want to consider removing their boats from the water altogether.”