An intense 14-hour accidental fire on the attack submarine Perle, which was in dry dock for repairs last June, made the front part of the boat unusable, according to the French Ministry of Defense. It suffered structural damage to steel components that could not be repaired.
However, the rear half of the 73 meter long submarine with a displacement of 2,600 tons was not damaged during the fire at a shipyard in Toulon, southern France.
Fortunately for the French Navy, one of the Pearl’s sister boats, the Saphir, which was withdrawn from service in 2019, was waiting to be dismantled at a shipyard in the north-western port of Cherbourg.
The front section of the Sapphire was structurally sound, and French officials determined that it could be paired with the rear section of the Perle to make a serviceable attack submarine.
The damaged pearl was moved from Toulon to Cherbourg on a semi-submersible ship in December.
According to a press release from French shipbuilder Naval Group, workers cut the pearl in half in February and did the same with the sapphire in March.
Earlier this month, the back half of the pearl and front half of the sapphire were placed on “walkers” at the Cherbourg shipyard so they could be carefully aligned and then welded together, the Naval Group press release said.
Naval Group spokeswoman Klara Nadaradjane said accession work would be completed in the coming months.
The resulting submarine, which is still referred to as the Pearl, will be about 1.4 meters longer than any of its predecessors to accommodate a “joint area” as the miles of cables and pipes pass through the submarine, it is said in the press release.
The crossing area also provides space for new living quarters and can accommodate the crew of 70 submarines.
All of this work is rehearsed with a three-dimensional digital model before attempting on board the submarine, the Naval Group said.
The task comprises 100,000 hours of engineering studies and 250,000 hours of industrial work by 300 people.
Nadaradjane said industry regulations did not allow the company to disclose costs of operation.
Commissioned in 1993, the Pearl was the newest of six Rubis-class nuclear submarines in the French fleet. The second boat in the class, the Saphir entered service in 1984 and served 35 years before it was decommissioned.
The Rubis-class submarines are slated to be replaced in the coming years with Barracuda’s new nuclear submarines, the first of which, the Suffren, was delivered to the French Navy in November. However, the sixth Barracuda submarine is not expected to join the fleet until 2030. Hence, half the pearl is needed to keep the number of French attack submarines at the required six, according to the Naval Group.
“Conducting this type of project under these circumstances, ie repair work that joins the front and rear ends of two sister ships together, is of course a first in the Naval Group’s modern history,” said Ferrer.
Modern submarine construction
But it’s not the first of its kind.
“The United States Navy did something similar when they replaced the bow of the damaged USS San Francisco, which ran aground in 2005 on a seamount near Guam, with the bow of the USS Honolulu, which was due to be retired,” said Thomas Shugart, a retired U.S. Navy submarine commander.
And those kinds of repairs start all over again, he said.
“Sure, it would be a lot of work, but probably a lot less than building a whole new submarine,” said Shugart, now a member of the Center for New American Security.
Shugart said current submarine construction is essentially doing what the French are doing now at the Cherbourg shipyard.
“All newly built US submarines are now being built in a modular manner, in which essentially submarine parts are put together, but much more planned than this repaired French submarine,” he said.
The Miami was set on fire by a disgruntled shipyard worker in 2012 when it was being repaired in Portsmouth, Maine. It would have cost too much to get back into service and it was scrapped.