on_the_cover_buttonmasthead buttonsubmit_feedbacksubmit_article
The Sea Shuttle Barge Arriving with a Hull Section off Groton, Conn. This highly specialized barge had to be strengthened to handle the larger modules now being shipped under the four-module build plan. The vertical steel columns projecting up from the deck are actually legs. At the shipyard, they will be lowered to the bottom to keep the barge firmly in position as the module is transported ashore.

Of the many technical breakthroughs made so far in building the Virginia (SSN-774) class, perhaps the most important—and certainly the most visually arresting—is reducing from ten to four the number of hull sections that reach the final assembly yards.

Experience has demonstrated that it is more efficient—and therefore less costly—to deliver fewer hull sections to the yards in a more advanced state of completion.

Consequently, as part of the ongoing effort to reduce cost so the Navy can acquire more submarines, General Dynamics Electric Boat and Northrop Grumman Shipbuilding are routinely handling larger and heavier hull sections than ever before.

The following photos provide a glimpse into how that work gets done. (To find out more about the origin and benefits of the four-module build plan, see the following article.)

 

map
image 1

The Sea Shuttle Barge Arriving with a Hull Section off Groton, Conn. This highly specialized barge had to be strengthened to handle the larger modules now being shipped under the four-module build plan. The vertical steel columns projecting up from the deck are actually legs. At the shipyard, they will be lowered to the bottom to keep the barge firmly in position as the module is transported ashore.

 

image 2

The Sea Shuttle Barge Docked at the Electric Boat Shipyard in Groton. The barge has docked beside the upriver end of the shipyard pier, and the three legs have been lowered to the bottom in preparation for transferring the hull section ashore. Beams and bracing support the hull section during transit. A bit of the bracing is visible to the right of the blue structure surrounding the nearest leg.

 

image 3

The Module Moves Ashore. In this long-distance shot taken from the roof of the Main Building Shed, the land transporter has slid beneath the beams supporting the module, lifted the entire load, and begun to carry it onto the pier. Before the introduction of new modular land transporters like this one, previous transporters had to remain beneath the module on the barge during the seaborne transit. This added to the total weight on the barge and thus reduced the maximum payload the barge could carry.

 

image 4

The Land Transporter Begins to Turn. This is a good view of how the transporter carries the hull section, still supported by the beams and bracing that held it in place on the barge. The modular nature of the wheeled sections that support the load is apparent. Adding modules enables the transporter to carry hull sections larger than the one shown here. Note that the wheels of the forward modules are beginning to make the 45-degree turn toward the landward end of the pier.

 

image 5

Turn Completed. After making the turn, the transporter shifts to the left before proceeding up the pier toward the Main Building Shed. The wheels align to make the shift without changing the orientation of the transporter. The power modules project from the front end of the transporter assembly. The end plate on the module makes it unnecessary to cover that end.

 

image 6

Moving Along the Pier. The transporter carries the hull section toward the building shed. To the left, the previous submarine assembled at the Groton shipyard has been lowered into the dry dock, where it is receiving the final touches prior to float-off.

 

image 7

The End Product Takes to the Water. The final assembly process, which begins with the arrival of the four large modules at the shipyard, culminates with the flooding of the dry dock so that a completed submarine can float off. In this case, the submarine is USS Missouri (SSN-780).

All photos courtesy of General Dynamics Electric Boat.

Top