MARSHFIELD — Dave and Karyn Walsh dreamed about life ­after retirement, sailing the East Coast from Florida to Massachusetts aboard their 40-foot Viking boat Naut Again.

But that dream came to an abrupt halt in the early-morning hours of Thursday, when their boat, along with two commercial vessels stored at a Marshfield marina for the winter, were destroyed by a suspicious fire under investigation by Fire Marshal Stephen D. Coan’s ­office.