He held a few zip ties with his teeth as he unfurled blue icicle string lights — an on-sale find from Walmart a couple of years ago. By the end of the day, more than 2,000 string lights decorated Welch’s 2006 270 Sea Ray Amberjack for the Casco Bay Summertime Parade of Lights, his masterpiece. The idea for the parade started as a chat with his buddies at Aspasia Marina about why there was a winter boat parade but not a summer one. Shawn Welch uncoils red tube lighting on boat in preparation for the Parade of Lights. He twirled the post while wrapping more string lights around it, pausing to add zip ties along the way to secure it.