As early as 20 years ago, the Japan Maritime Self-Defense Force saw the practical value of hydrofoils and believed that torpedo boats as a coastal defense force no longer meet the needs of modern maritime operations, and the successor missiles of torpedo boats Boats, especially missile hydrofoil boats with high speed advantages will have great development prospects. This kind of boat is equipped with hydrofoils like airplane wings on the bottom. After the hull reaches a certain speed, the lift generated by the hydrofoils will completely lift the hull out of the water. It is fast and easy to maneuver; its hull is small and very concealed; it is loaded with powerful missiles and has strong assault power. Therefore, the Japan Maritime Self-Defense Force has long been brewing and planning to develop such high-speed attack boats. However, because the design and manufacturing technology of hydrofoils was not mature at that time, and taking into account Japan's special sea conditions (such as strong winds and high waves in winter), it was not until 1990 that the defense plan was finalized, and it was decided to build the first batch of two missile boats. Hydrofoil.
As early as before World War II, some countries had conducted research on hydrofoils, but progress was slow and it was not until the 1960s that significant development was achieved. In 1968, the U.S. Navy built two hydrofoil patrol gunboats from Grumman and Boeing respectively. Since then, military hydrofoils have entered the practical stage. The fully immersed hydrofoil patrol gunboat "Tukmukri" developed by Boeing Company sailed to the Vietnam Sea in 1969 and was engaged in offshore operations for 6 months. The boat was transferred to the Italian Navy in July 1974. From 1982 to 1984, the Italian Navy built 6 "Harrier" hydrofoils imitating the "Tucumculi". The missile hydrofoil boat decided to build by the Japan Maritime Self-Defense Force in 1990 was designed and built based on the Italian "Harrier" hydrofoil boat.
Modern hydrofoils are divided into split hydrofoils, shallow submersible hydrofoils and fully submerged hydrofoils according to their hydrofoil forms. The first two missile hydrofoil boats of the Japan Maritime Self-Defense Force are fully submersible boats with a tail hydrofoil that is significantly longer than the bow hydrofoil. The construction of No. 1 and No. 2 missile hydrofoil boats started in February 1991, was launched in July 1992, was completed in March 1993, and has been in active service.
The Japan Maritime Self-Defense Force attempts to take advantage of the sea conditions in the coastal waters of the island country that are convenient for high-speed attack boats to hide, and give full play to the fast and flexible characteristics of hydrofoils. Under the guidance of the aviation force, it can attack enemy surface ships with ship-borne missiles , to achieve the purpose of intercepting and destroying enemy ships.
Following the first two missile hydrofoil boats, the Maritime Self-Defense Force will continue to develop this high-speed attack boat based on the experience of the first type of boat. *** plans to build 6 boats to meet the needs of the future the needs of offshore warfare.
Submarines in various countries around the world today still have a short underwater latency time due to various factors such as their endurance, the survival period of personnel in the existing cabin environment, and the effective time of the submersible oxygen regeneration device. Long, it cannot meet the requirements of nuclear submarines lurking underwater for a long time as a second strike force. Currently, shipbuilding experts from various countries are making comprehensive improvements to the latent capabilities of nuclear submarines, especially focusing on equipment that currently produces oxygen in submarine cabins, such as oxygen regeneration panels, oxygen bottles, and electrolytic oxygen generators.
The oxygen-generating equipment currently in use still uses old methods, and it is impossible to use them to increase the incubation time for a long time within a limited load range. Naval architects are developing a compact oxygen-generating device. Preliminary predictions are that this compact oxygen-generating device will be a box-packed grid composed of a special drug. Such a box of oxygen-generating equipment can provide a submarine with the oxygen it needs to lurk for one year. At the same time, this oxygen-generating equipment can also absorb various odorous gases that have nothing to do with human metabolism and keep the air in the cabin clean.
In terms of ship power, the scientific research departments of various countries will improve the nuclear fuel and engines of nuclear submarines to extend the submarine time. The way nuclear power propels submarines forward is currently the best underwater propulsion method for submarines. Some military experts analyze that unless there is unexpected progress in the development of superconducting engines, there will be no more advanced submarine propulsion methods in the past century. Therefore, nuclear propulsion is likely to be the preferred propulsion method for future submarines. However, the power and high-speed operation of nuclear-powered engines are always limited. To increase the underwater speed, we have to start by reducing the resistance encountered by submarines in underwater navigation.
For this reason, shipbuilding engineers believe that the purpose of reducing resistance and increasing speed can be achieved by reducing the openings in the hull and improving the smoothness of the hull, and by spraying a high molecular polymer on the surface of the hull. Some engineers have proposed building a "skin-driven submarine" that can bend forward like a snake to increase the speed of the submarine. Although this solution is not currently accepted by most naval architects and military experts. But it may give birth to the possibility of a new type of high-speed assault weapon.
The biggest advantage of submarines is their high concealment. However, due to the development of various underwater detection technologies, the noise of existing submarines and the echo reflected by the hull are easily received by the other party, and its concealment performance is increasingly reduced. In order to be "unconscious of God and unaware of ghosts", we can only work hard to reduce the noise of the submarine and reduce the echo from the hull.
The noise of submarines is mainly caused by the rotation of submarine propellers and other mechanical work. At present, the noise reduction work of submarines in various countries is mainly focused on improving the structure of submarine engines and propellers, as well as laying sound insulation devices in various parts that generate noise.
At present, some researchers believe that the main method to reduce the echo of the hull is to spray paint on the outer surface of the submarine that can absorb radio waves and increase the submarine's diving depth. Increasing the submarine's diving depth is mainly to increase the pressure resistance of the hull shell. The United States is currently studying a technology to replace metal submarine shells with reinforced plastics. The plastic is a new epoxy polymer that is smooth, hard and highly resistant to moisture. Tests have proven that submarines made of reinforced plastic can dive to a maximum depth of less than 4,000 meters. Attack submarines are mainly used for short-range raids, so their weapons and equipment will change with the changes in short-range weapons. According to analysis, particle beam weapons and laser weapons will become the main weapons of future surface ships. However, since these two weapons are not suitable for use as weapons for future submarines, military experts are eager to create a particle beam-like weapon that has no or very small energy attenuation when launched underwater to compensate for underwater attacks. The disadvantage of submarines is that they have no backup weapons. Some military experts are working hard on this. It is believed that attack submarines equipped with this new type of particle beam weapon will be available in the 21st century.
The development of things is endless. Submarines will become more advanced with the development of technologies such as accelerating speed, increasing diving depth, reducing noise and extending reactor life.