In March 2021 a French SSN (nuclear attack submarine) was successfully repaired by having the front section of a recently (2019) retired SSN of the same Rubis class replacing the same section of the SSN Perle, whose front half was severely damaged by a shipyard fire in 2020. Following the example of a similar procedure for two American SSNs in 2006, the French shipyard devoted 100,000 man hours to planning the operation and 250,000 hours by 300 shipyard workers to successfully take the usable front half from SSN Saphir and put on the SSN Perle, after the same fire damaged front end of the Perle sub was removed. Estimated cost was under $40 million and was considered a worthwhile expense because France only builds six SSNs every thirty to forty years. The six, 2,600-ton (surface displacement) Rubis class SSNs entered service between 1983 and 1993. Saphir was the first one to be decommissioned, after 35 years’ service. The Perle was the youngest of the class, and was undergoing an upgrade that was to keep it in service into the late 2020s.

By late 2021 the first of six new French Barracuda class SSNs, the Suffern, will enter service. All six will enter service in the 2020s. Putting a new class of SSNs into service in timed to overlap with the retirement of the previous class so that at least six SSNs are always in service,

Back in 2006, France decided to buy six new Barracuda class SSNs, for about $1.5 billion each. The 4,700-ton boats are smaller than America's new 7,300- ton Virginia class subs, which cost about $2.8 billion each. A new class of Russian SSNs will displace 6,000 tons. The older American Los Angeles class boats were about 7,000 tons. Size does matter, as it indicates how much space you have available for sensors and weapons. Larger boats are better equipped and more heavily armed. The new Russian SSN construction was delayed by shortages of cash and qualified shipyard personnel. The U.S. already had two Virginia's in service by 2006 and now there are 17 with 11 under construction. Two Virginia's a year are entering service, for an eventual total of about 60 subs.

The U.S. Navy was also the first to keep an older SSN in service by replacing a damaged section of one with the same section from a recently retired boat. The work took two years and cost $79 million. The expense was justified by the fact that damaged San Francisco had recently (2002) completed a mid-life refueling and upgrade that was to keep the boat in service until 2017. The San Francisco is still in service and expected to be retired later in the decade. This is because in 2016 the San Francisco was withdrawn from sea service and, for at least ten more years, given a stationary assignment as one of two moored training ships for new Los Angeles SSN crew. The Los Angeles class SSNs were put into service between 1976 and 1995 and were designed to serve up to 40 years. All 62 Los Angeles class boats are to be retired by the early 2030s, replaced by about the same number of Virginia class SSNs. Currently about half the Virginias have been completed, with the first entering service in 2004.

Meanwhile in France construction on the first Barracuda began in 2007 and it was supposed to be launched by 2012. That launch date was tentative because the development of the Barracuda nuclear power plant began in 2003 and soon ran into problems. Problems with the power plant were no surprise because France, unlike Britain, did not license the American submarine power plants. This would make it more difficult to export French nuclear subs and so on. The French chose a different design that used commercial (not weapons) grade nuclear fuel. This meant French nuclear subs had to be refueled more often but this was made easier by building the hull with special large hatches that could be quickly opened for the once every 7-10 years refueling then sealed again. France is the only nation using this type of ship power plant and has to handle development and maintenance procedures itself. With a small fleet of nuclear subs, this drives up the cost per sub. Britain, by licensing the American tech, gets the benefit of a much larger American nuke fleet and the larger budget for work on the power plants. Ever since the first Barracuda began construction, the delays have come from power plant problems. By 2012 it was believed that launch date could be 2017 but delays perfecting the power plant continued. The sub could not be launched until the power plant was completed and the hull made watertight

The Barracudas will rely on a lot of automation and have a crew of sixty, plus berths for 12 passengers. These will usually be commandos and their gear will be stored in a pod attached to subs sail. The Barracuda design emphasized silencing, making it more difficult to detect. The Barracuda's have four 533mm (21 inch) torpedo tubes, which can also be used to launch missiles, mines or torpedoes. Twenty weapons are carried with the mix of torpedoes, mines and missiles depending on the mission. French SSNs have two crews which each operating the boat for three months. Enough food is carried to sustain the crew for 70 days.