New payload tubes from BAE Systems will upgrade the firepower of the U.S. Navy's Virginia-class submarines. (Andrew C. Jarocki/Staff)

WASHINGTON ― The U.S. Navy’s latest Block III Virginia-class attack submarine has been delivered to the service nearly four months late, but the Navy thinks the program is getting back on a steady course with future boats.

Huntington Ingalls delivered the attack submarine Indiana to the Navy on Monday, with its commissioning slated for September, according to a Naval Sea Systems Command news release. The Indiana, designated SSN-789, was supposed to be delivered in February 2018, according to Navy budget documents, but supplier issues, a doubled production rate and cuts to production time from 84 months to 66 months contributed to delays for the Navy’s gold-star program in recent years.

In an April interview, the Navy’s top submarine program manager, Rear Adm. Michael Jabaley, told Defense News that all the Block III boats have delivered plus or minus 5 percent of the contracted span ― or about three months.

The Washington was delivered three months late. The Colorado, which was commissioned in March, was three weeks late. The Indiana should be the last boat in the series to be delivered late, Jabaley said.

“For SSN-790 (South Dakota), we’re working very hard to make sure that she delivers on time,” Jabaley said. “Right now, she is scheduled to deliver a little bit early to contract delivery date, which will be in August of this year.

“Then [SSN]-791 is the last boat of Block III. She’s scheduled to deliver next February, and we’re working very closely with the shipbuilders to ensure that we get her out on time as well.”

On issues related to the suppliers, Jabaley told Defense News that his office was pressing prime contractors Electric Boat and Huntington Ingalls Industries’ Newport News division to stay on top of it, especially as the Navy and Congress weigh building as many as three Virginia-class subs annually in years the Navy is not building Columbia-class subs.

“We have been stressing with Electric Boat and Newport News for the last three to four years that they need to do a better job in light of, again, this tremendous ramp up in construction work that’s coming and that they need to understand the supply chain,” Jabaley said.

“I look at it in terms of: What is the capacity of each of these suppliers? Will they be able to handle this change from two boats per year to as much as four and a half boats per year? What is the quality? Are they providing a quality product now? Is their process resilient, and how will it hold up under the additional work?”

Jabaley said the focus on the supplier base has shown some fruit, but he added that the Navy will continue to apply pressure as it moves into higher production rates going forward.

As the Navy moves from Block III Virginia-class subs to Block IV, the focus will be on driving down the production time from 66 to 60 months, then it will move onto the major redesign for Block V.

Block V includes the new payload module. Adding the new section of the boat ― designed to boost vertical launch capacity ― will drive construction times back up as the yards adjust to the new design.

Despite the redesign work, the Navy feels like its on a good path with Block V.

“Virginia originally was 42 percent when we started construction,” Jabaley said. “So we’re well beyond anything that we’ve ever accomplished before in terms of design-completed construction start. For the Virginia payload module, we’re tracking to about 75 to 80 percent completed-construction start, which is good.”