MEDFORD — A fire broke out on a boat in the Wellington Yacht Club's storage lot early Friday, causing gas explosions that severely damaged two other boats and shot flames into the air above the boatyard, State Police said.

The blaze started about 6:15 a.m. in the Medford lot, and no one was injured, State Trooper James Vines said. The fire began on one boat and spread to another, and the plastic covers of six other boats burned, Vine said.

The state fire marshal's office and Medford Fire Department are investigating the fire, but Vines said the fact that it broke out in the dark amid rain makes it suspicious.