The project consists of the replacement of four main drydock dewatering pump motors, controllers, and wiring. The project overhauls these four dewatering pumps, including thrust bearings, and replaces the four main dewatering pump discharge operators. As a result of the increased floor loads from the new pump motors and revised pump configuration, structural modifications to the existing historic structure have been required. The pumpwell and its equipment remained operable during the execution of the contract. Pumpwell 2 is a five-level, 75-foot tall building structure on the National Register of Historic Places. It is part of the 189-acre historic section of the shipyard’s 1,347 acres, constructed just prior to World War II. No shop drawings are available for the existing pumps.  Nova was required to reverse-engineer the pumps to custom order new replacements.

Electrical work includes revising the primary building electrical service from 2,300V to 11.5KV, which required removal and replacement of existing medium voltage underground feeder circuits that service the pumpwell.  Feeder removal and replacement was performed in the existing manholes and ductbank leading to the pumpwell.  Two new sections of 15 kV switchgear were installed at the new Substation 10, which services Pumpwell 2, and a retrofit of two sets of existing switchgear at Substation 9 and Substation 5B was also performed.  A new MCC, MCC valve controller, a power transformer, dry-type transformer, and a new 400A panel were installed to support the new electrical service for the upgraded motors.

COMPLETION:

2021