Big projects are on the horizon in the next couple of years on the barrier island of Longboat Key, including the installation of an underwater sewage pipeline, which Town Manager Howard Tipton describes as “the most complicated project the town has ever taken on.”Expected to break ground in the coming months, the installation of a 20-inch-wide plastic pipe from Longboat Key, under Sarasota Bay to the mainland is No. 1 on the town’s list of prior…