These are the massive ships that can transport other ships for repairs

After colliding with a civilian cargo ship earlier this year, the USS Fitzgerald sustained over $500 million worth of damage to its structure and systems.

Though the Arleigh Burke-class warship was brought back to port at Yokosuka, Japan, it will likely be unable to transit the ocean in its current condition, officials say.

However, as the Navy and its contractors don't maintain large maintenance facilities and dry docks in Japan capable of carrying out the repairs the Fitzgerald needs, it will have to somehow be delivered to the United States for fixing.

To bring the Fitzgerald home, the Navy will make use of massive heavy-lift ships, designed to hoist smaller vessels onto a platform and carry them across the world's waterways. The alternate name of these unique ships — float on/float offs (FLO/FLO) — hints at how they're able to load and carry ships weighing thousands of tons.

To load a vessel aboard a heavy-lift ship, it takes on water into ballast tanks, submerging its main deck area enough that its cargo can be floated into position, sometimes onto a cradle which will keep it stabilized during transport. When its cargo is in place, the ship releases its ballast and is now able to move under its own power.

This won't be the first time the Navy has had to use a civilian heavy-lift ship to bring one of its own back to American shores.

In 1988, the USS Samuel B. Roberts, an Oliver Hazard Perry-class frigate, was struck by an Iranian mine during Operation Earnest Will. The Roberts was marred with a 15-foot gash in its hull, and its engines were rendered inoperable.

To return the Roberts back to the US, the Navy contracted Dutch shipping firm Wijsmuller Transport to the tune of $1.3 million to provide a heavy-lift ship — MV Mighty Servant 2 —  that would carry the stricken frigate back to Newport, RI, where further damage assessments would take place.

Years later, in 2000, the USS Cole, another Arleigh Burke-class destroyer, was damaged on its port side at the waterline during a suicide attack which claimed the lives of 17 sailors and injured 39 more. Though the ship was still afloat in the aftermath of the attack, it was quickly determined that it would not be able to proceed back to mainland America under its own power for repairs.

As such, the Navy contracted a Norwegian company, Offshore Heavy Transport, to sail a heavy-lift vessel to Yemen where the Cole remained after the attack, in order to bring the warship home.

Offshore Heavy Transport provided the Navy with the MV Blue Marlin as part of the $4.5 million contract to bring the Cole stateside.

In addition to carting damaged warships around the globe, the Navy's Military Sealift Command also charters heavy-lift ships to carry its smaller craft to various operating locations in foreign seas, including minesweepers and patrol boats.

A number of these heavy-lift ships are still in service today, save for the Mighty Servant 2, which was lost at sea near Indonesia in 1999. It's possible that the vessel which brought the Cole back to the United States — the Blue Marlin — could be the same one to return Cole's sister ship, the Fitzgerald, to America to begin the repair process.

It was recently reported that the move could begin as early as September, depending on when the contract for transport is issued and inked.