KITTERY, Maine (AP) Navy Secretary Carlos Del Toro is going to be on hand for the groundbreaking of a $1.7 billion project that will expand the number of dry docks at Portsmouth Naval Shipyard.

The seven-year project that follows the creation of a super flood basin will allow two submarines to utilize the dry dock simultaneously. It will accommodate both Los Angeles- and Virginia-class attack submarines.

The event on Wednesday is closed to the public.

The project is a key part of the Navy’s $21 billion modernization efforts at four public shipyards that repair and overhaul ships, with a goal of returning ships to the fleet faster at a time of growing threats.

About 60% of today’s fleet was commissioned in 2001 or before — causing growing maintenance and operation costs.

Eliminating a maintenance backlog and getting ships back into the fleet is key as tensions grow in the South China Sea, Russia’s navy is emboldened, Iranian speedboats are harassing vessels in the Persian Gulf.