Moran Towing Tugboats, Portsmouth NH

Photo by PortsmouthNH.com
Moran Towing maintains at least three and often four tugs in Portsmouth to assist with river traffic that brings several million tons of cargo a year - coal, natural gas, road salt, and products for a Foreign Trade Zone - up the the Piscataqua River and through Portsmouth Harbor.
It can be a challenging job. While deep and ice-free, the Piscataqua is also the third-fastest tidal river in North America and extremely narrow by shipping standards.
As a result, the tugs operate only at "slack tide," periods of about an hour twice a day when the incoming tide temporarily balances the outgoing current of the river.
Location: 34 Ceres St., Portsmouth, NH map
Hours: Not open to public; viewable from nearby streets.