「1本のホースだけで生かされる」いよいよ始まる「飽和潜水」知床沈没船捜索 リスク冒して「水圧」と戦う もうひとホリ 2022年5月10日放送

The search continues off the coast of the Shiretoko Peninsula using unmanned underwater vehicles. Detailed searches require human diving. The tourist boat "KAZUI" sank to the ocean floor at a depth of 120 meters. Currently, search and investigation are being carried out using unmanned underwater vehicles, or robots. However, a thorough search and investigation into the cause of the accident require the salvage of the vessel. The key to this is a process called "saturation diving." [Experiment using a plastic bottle at Gifu Diving Center (Gifu City)] The deeper you go underwater, the greater the pressure. An empty plastic bottle easily collapses at a depth of just 5 meters, and at 25 meters, it loses its original shape. At a depth of 120 meters, the water pressure is 4.8 times greater, so unmanned underwater vehicles are responsible for the search. However, due to the large size of unmanned underwater vehicles, search and investigation onboard are difficult, and humans must actually dive to check detailed areas. This involves a special diving method called "saturation diving." We spoke to an expert to find out more about this process. Atsushi Abe, Director of the Japan Society of Underwater Rescue, said, "The divers are kept alive by a single hose. It's extremely risky." A "saturation dive" will be conducted soon to search and investigate the sunken vessel, "KAZU1." Divers enter a "special chamber" with adjustable pressure inside the vessel, and while taking in a mixture of helium and oxygen, they spend about a day acclimatizing their bodies to the water pressure corresponding to the target depth. Once their bodies have acclimatized, they can continue working, moving back and forth between the chamber and the ocean repeatedly. However, they can only work for about 30 minutes at a time. Jun Abe, a former JMSDF physical education instructor and director of the Japan Society for Marine Rescue, explains that divers face considerable danger. Director Abe "Warm water is supplied to the diving suit. Breathing gas, communications, and light—all these things keep the diver alive through a single hose. A malfunction in even one hose can directly endanger the diver's life. It's extremely risky." Saturation diving allows humans to thoroughly search the inside of the ship. Director Abe "I think the search will involve looking for people on top of the ship, or in the pools of jackets." The hull will be inspected in detail, and the team will also be tasked with attaching wires to the hull for salvage. However, raising a ship that has sunk to the deep seabed is not so easy. A JNN reporter's report from Kagoshima in 2002 "It was slowly being raised by a crane." In 2002, a North Korean spy ship was salvaged 390 kilometers off the coast of Amami Oshima, Kagoshima Prefecture. It was raised from the ocean floor at a depth of 90 meters, eight and a half months after it sank. In 2010, a fishing boat that was wrecked off the coast of the Goto Islands in Nagasaki Prefecture and sunk to the bottom at a depth of approximately 154 meters was raised, and it took five months for the bodies of all 10 crew members to be recovered. Regarding future work off the coast of Shiretoko, Abe, a director of the Japan Society for Marine Rescue, said: Director Abe: "Saturation divers will be dispatched in May to gather information to consider various options for raising the current ship. The salvage will likely take place after June, and it will depend on the workload." And here's the information received on the afternoon of the 10th. A vessel carrying specialized equipment departed Mojiko Port in Fukuoka to conduct saturation diving at the site of the "KAZU1" sinking off the coast of Shiretoko. According to the Japan Coast Guard, the vessel is expected to arrive at the site no earlier than the 17th. #Shiretoko #TouristBoat #Hokkaido #HBC #JSDF #JMSDF #JapanCoastGuard #MojiPort #Diver #WaterPressure #GifuDivingCenter ◆Please subscribe to the HBC News channel.    / @hbc7142