The Navy says a minor issue involving improper documentation of a part on the future attack submarine Vermont, set to be commissioned in April, has prompted a review by submarine builders Electric Boat in Groton and Newport News Shipbuilding in Virginia to ensure the problem doesn't happen again.

A fiber optic cable aboard the submarine wasn't working properly, so a spare cable was put in its place, but there was no documentation of the spare cable.

EB discovered the issue in early January, during the Vermont's fast cruise, when a submarine operates as if underway so that its crew can be assessed on its level of preparedness and systems aboard the submarine can be tested in a controlled environment. The company reported the issue to the Navy.

Rear Adm. David Goggins, the Navy's program executive officer for submarines, described it as a "minor documentation issue" and said there's no effect on the submarine's nuclear propulsion plant, critical systems or the safety of the ship or reactor plant.

Liz Power, spokeswoman for EB, declined to comment.

The delivery of the Vermont to the Navy will be delayed but the commissioning still is expected to happen as scheduled on April 18 at the Naval Submarine Base in Groton.

The two shipyards are "taking a pause" to review their procedures, identify areas of improvement and whether any other documentation issues have occurred, Goggins said. He is expecting to receive a report signifying the completion of that review early next week. The "pause" has been in effect for a couple of weeks.

In the meantime, Vermont is not continuing with its sea trials, which test a submarine's seaworthiness, until the review is complete.

The Virginia-class attack submarine program largely has been hailed as one of most successful Navy shipbuilding programs. Goggins said the program has "a history of high standards and attention to detail," and that's expected to continue.

The Navy already is keeping a close eye on the Virginia program to ensure it stays on track and does not impede the ability of EB, Newport News and their suppliers to construct a new class of ballistic missile submarine, known as the Columbia program, a top priority given these submarines represent one leg of the U.S. nuclear triad.

The Virginia program has faced delays due to welding issues and materials not being delivered on time, and the Vermont has been affected by the delay of materials.

U.S. Rep Joe Courtney, D-2nd District, said to EB's credit, the company reported the latest issue with the Vermont.

"In some ways that bolsters the Navy's confidence that they are determined to get it right," Courtney said. Reiterating what Goggins said, Courtney said the issue did not extend to operations or nuclear propulsion. "That's where you would have crisis of confidence."

j.bergman@theday.com