Portsmouth Naval Shipyard, Kittery, ME
Dry Dock No. 3

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Dry Dock No. 3, originally constructed in 1962, is used for docking nuclear powered submarines. In 2016, HEGER was part of a teaming arrangement hired to modernize and improve the facility.

As part of the project, HEGER provided complete functional design drawings and specifications for a replacement caisson gate. HEGER was responsible for the design of the structural hull and naval architecture aspects of the floating gate including stability and draft requirements.

As part of the design team, HEGER coordinated with COLBY ENIGNEERING who provided mechanical and electrical designs for the caisson gate.

The new gate was constructed by STEEL AMERICAN in Norfolk, Virginia and delivered to Portsmouth Naval Shipyard in 2019 where it continues to operate successfully.

Caisson Gate #3 PSNY at launch
Figure 1 – Caisson at Launch
Caisson Gate #3 afloat Portsmouth Naval Shipyard
Figure 2 – Caisson Afloat
Portsmouth Naval Shipyard, Kittery, ME
Dry Dock No. 2
Norfolk Naval Shipyard, Portsmouth, VA
Dry Dock No. 3