The Indonesian navy KRI Nanggala-402 went missing on Wednesday. Alex Widojo / Anadolu Agency / Getty Images The search for a missing Indonesian Navy submarine has been going on for days, and time is running out, hopes seem to have faded. “The submarines are designed to be hard to detect, this is a problem that can happen when one sinks,” said Bryan Clark, a former US Navy submarine officer. Submarines are built to penetrate enemy waters, engage and engage enemy navies, shoot at ground targets with cruise and ballistic missiles, and even deliver force. amount secretly entering enemy territory / territorial waters. Not all submarines can perform every task, but regardless of the mission and the ship’s capabilities, stealth is considered to be of primary importance. The KRI Nanggala-402 is a German-made diesel-electric attack submarine that is more than 40 years old. Due to the age of the submarine, it may lack the coating and stealth features of newer ships, even after being refurbished in 2012, giving search and rescue teams a bit of an edge. as they try to look for it, but other challenges will overwhelm any potential advantage. In the event of an emergency, the submarine can either trigger a “ping” device on the ship or send a buoy to monitor (if the Indonesian submarine has these systems and the systems are in operation as well. the submarine crew knew how to use them and did not lose their ability to act). A “ping” signaling device is extremely valuable because it allows search and rescue teams to use passive sonar to scan a larger ocean area with other tools. There is no indication that KRI Nanggala-402 is making a sound that would aid with the search. Mr. Clark, a defense expert at the US Hudson Institute, speculates that if the ship makes a sound, it may have been located. “If it makes a sound no matter what form it is, it will be much easier to find,” he said. Without a ping or other type of noise, search and rescue teams are limited to using active sonar, narrowing the scanning range and prolonging the time it takes to search for a site. field. While passive sonar involves listening to sounds coming from objects in the ocean, sonar actively emit pings and then listens for echoes from objects in the ocean. The Indonesian navy identified the submarine disappeared in the waters north of Bali island. Search teams soon noticed oil slicks in their search area, narrowing the scope of interest. In this common area, search units found an object with “strong magnetic resonance” that could be emitted from the missing submarine. While these developments have significantly reduced the overall size of the search area, there is still a lot to consider. Indonesia has dozens of ships and aircraft, supported by international forces participating in the search. The Indonesian navy said the ship may have sunk at a depth of more than 600 meters, which would certainly complicate the search. Not only does that depth exceed the maximum depth of the ship, potentially putting the hull in danger of rupture, but it could also leave it out of the reach of existing recovery options. Finding things on the ocean floor is also quite difficult, Mr. Clark said. “Like we’ve seen with so many airline crashes, it’s hard to find something, even big, when it falls to the sea floor, because it’s mixed up in the mess down there,” he said. The ARA San Juan submarine of the Argentine navy went missing in 2017. It wasn’t until a year later that search teams found the ship, 44 crew members killed, on the ocean floor at a depth of about 1,000m. “If a diesel submarine as small as an Indonesian submarine sinks more than 600 meters, it is unlikely to survive,” Clark said.

Ship with structural damage with steel parts and cannot be restored. But the second half of the 73-meter submarine was unaffected in the fire. CNN said. Fortunately for the French Navy, a submarine of the Saphir class was decommissioned in 2019, awaiting dismantlement at a shipyard in the port of Cherbourg, northwest France. The front section of the Saphir is still very good. French officials decided to take the first part of the Saphir, combined with the rear of Perle to form a new submarine. The Perle submarine was transferred from the city of Toulon to Cherbourg on a dedicated train in December 2020. At the shipyard, workers cut the Perle in half in February and did the same with the Saphir in March. The Perle submarine was cut in half at the Cherbourg shipyard. Photo: Naval Group. In early April, the second half of the Perle and the front half of the Saphir were fixed to tow them, then welded to connect the two hull halves together. The connection of the two hull parts will be completed in the coming months, said Klara Nadaradjane, spokesman for Naval Group, main contractor. The new submarine is still called the Perle. It will be 1.4 m longer than the original, as an additional component connecting the two halves of the hull is needed. Spokesperson Nadaradjane said the connection of the two halves of the hull was simulated with a 3-dimensional digital model, before being put into practice. However, a Naval Group spokesman did not disclose the cost. The Perle, commissioned in 1993, is the newest of six French Rubis-class nuclear attack submarines. Rubis-class submarines are expected to be replaced by more modern Barracuda-class nuclear attack submarines. However, it was not until 2030 that the last of the Barracuda-class submarines was delivered to the French Navy, forcing them to find a way to repair the Perle submarine. This is the first time the French shipbuilding industry has cut two different ships in half to merge them into one complete ship. Previously, this technique was used by the US to repair their damaged submarines.

Fortunately, the second half of the 2,600-ton submarine, 73 meters long, displaced the water, remained undamaged after the fire. And in the difficult emergence of wisdom, French naval officials had the idea of ​​pairing the rest with its “sister” – the Saphir submarine. Perle nuclear submarine intact. Photo: Reddit Although decommissioned in 2019, and waiting to be dismantled, the Saphir front section remains relatively stable in construction. Therefore, French authorities determined that the ship could still be combined with the back of Perle to form a new attack submarine. Perle was subsequently relocated from Toulon to Cherbourg in December of last year. The workers cut it in half and the Saphir. According to French naval contractor Naval Group, earlier this month, the second half of the Perle and the front half of the Saphir were put on “conveyor” at the shipyard in Cherbourg, so that they can be carefully calibrated and welded. together. Perle submarines after being burned by fire nearly half. Photo: Marine Nationale A Naval Group spokesperson said assembly will continue to be completed in the coming months. The complete submarine, still named Perle, will be about 1.5 meters longer than its “predecessors” thanks to an additional “intersection zone”. The intersection zone on the new version of the Perle submarine will add a bit of living space for about 70 sailors operating inside the ship. Digital model According to Naval Group, all assemblies are simulated using 3D digital methods before being applied to a real ship. This is the effort spent more than 100,000 hours of technical research and 250,000 hours of manual work by more than 300 technicians and shipbuilders. Two pieces of the Perle submarine after being cut in half at the Cherbourg Shipyard, France. Photo: AP Franck Ferrer, Director of Naval Group Services, said in January the new version is expected to return to Toulon by the end of this year, for further engineering and upgrade of the combat system. . The ship will rejoin the French Navy fleet in early 2023. “The implementation of the project for these cases, namely the repairing and joining of parts of two sister ships together, was the first thing Naval Group did in modern history,” said Ferrer. said. Rare luck The Perle was not the first instance of two parts of two different ships being assembled together. According to Thomas Shugart, a retired commander of the American attack submarine, the US Navy did the same thing by replacing the damaged bow of the USS San Francisco with the bow of the soon-to-be retired USS Honolulu. The process of assembling two-part Perle submarines with Saphir. Video: Le Télégramme However, the Perle submarine can “revive” is still considered a rare luck compared to similar cases in the past. In 2012, a disgruntled worker caused a serious fire on the USS Miami submarine, while the ship was undergoing repairs at the port of Portsmouth, Maine (USA). The ship then became a waste product due to the high cost of restoration. By 2020, the amphibious assault ship USS Bonhomme Richard is also damaged by fire while being upgraded in San Diego port (USA). After determining it would take up to $ 3.2 billion and seven years to repair, the USS Bonhomme Richard was finally removed from service with the US Navy.