The Beliveaus' townhouse affords a few views of Boston Harbor, which is a working port. Ships of all shapes and sizes steam past Charlestown everyday, and regularly dock in the channel. Heatin and plumbing expert Richard Trethewey goes aboard one of ... (more)the harbor's frequent visitors, a liquid-natural-gas tanker, to learn more about the vessel operates. Meanwhile, at the townhouse, work continues on the Beliveaus' prime viewing spot, their roof deck. Seeking some inspiration for its design, Steve visits a spectacular roof deck nearby.