The vast sea is a three-dimensional "stage" for military ships. On this "stage", different ships play different roles. But when it comes to which warship has a more "dense" and "compact" onboard structure, a submarine rescue ship is undoubtedly one. Adapting to the needs of emergency rescue, submarine rescue ships give the impression of "wishing every inch of space on board could be utilized" in terms of shipborne equipment. In recent years, the practice of various countries in rescuing and salvaging several wrecked submarines has proved the necessity of this equipment configuration mode and the importance of submarine rescue work. This is because, in addition to war damage, factors such as design defects, operational errors, accidental collisions, and equipment failures can all cause accidents to submarines during navigation. Therefore, submarine lifesaving has become an important "backstop" to ensure the safety of sailors and maintain the combat effectiveness of the submarine force. The practice of rescuing wrecked submarines in various countries over the years shows that the research on submarine lifesaving and the development and improvement of relevant lifesaving facilities are still ongoing. So, what are the life-saving means and methods in case of a submarine accident? What is the current development of submarine life-saving equipment in various countries? Please see this issue of "Weapons Wide Angle". Russian Navy's 21300 submarine rescue ship. Submarines also have a "portable emergency kit" in the deep underwater world, and they are worthy of being the "protagonist". However, underwater is more treacherous than water. For submarines, this external influence is only one of the many factors that contribute to their risk formation. Design defects, operational errors, accidental collisions, equipment failures, as well as fire and explosion accidents, can all be the inducements for submarine distress. Therefore, for submarines, every aspect of their development and use deserves high attention, including scientific planning and design, advanced construction techniques, complete operating procedures, and strict training. In addition, equipped with some "just in case" submarine life-saving equipment has also become an inevitable choice. However, submarines are mainly used for underwater warfare. This positioning determines that it must carry sufficient weapons and equipment such as torpedoes and submarine-launched missiles. With the "joining" of submarine launched drones and small unmanned underwater vehicles, the internal space of submarines is further occupied, so there is not much space allocated for life-saving equipment and devices. Judging from the specific situation of submarines in various countries, most of these small spaces are used to set up "personal first aid kits" for submarines, so that sailors can escape in times of crisis. Currently, there are three main types of "portable first aid kits" for submarines: one is a single person floating escape device. On the premise of using torpedo launch tubes as a common channel, some submarines will be equipped with 2-3 escape hatches on their hull. The crew of the wrecked submarine can escape from here using a single person floating escape device. However, this device can typically only be used at depths up to 180 meters. Many submarines in the US and UK navies have designed such escape hatches. The second is a pressure resistant watertight compartment. The pressure resistant watertight compartment is usually located in the middle of the pressure resistant hull of a submarine. Once the submarine is in distress, it can serve as an escape capsule for underwater escape. Sweden's Gottland class submarines use this method of escape. The third is a floating rescue capsule or life ball. one