A year and a half after the Memorial Bridge was closed, severing Route 1 — the main artery for traffic between Portsmouth and Kittery, Maine — the first section of a new span was eased into place on Tuesday.

With helicopters hovering overhead in a clear and cool winter sky and more than 100 rubberneckers looking on, two smoke-belching tugboats eased the new 300-foot-long southbound span into place between reconstructed piers around 9:30 a.m. at dead low tide.