The Ted Williams Tunnel (TWT) was the first major link constructed as part of Boston's Big Dig. It is constructed from twelve "binocular" shaped steel sections fabricated in a Baltimore shipyard. These sections were then brought to the Black Falcon Pier near the site and each was fitted with a large surrounding mass of concrete (so that the tunnel section was more neutrally buoyant). Using additional flotation, the tunnel sections were then floated into place, lowered into a dredged channel, and joined to the other sections. At this point, the steel panels sealing the now-joined sections could be cut out and the finishing operations could be completed.