In the first half of this year, the Swedish Defense Equipment Agency announced the completion of the TP47 torpedo launch test on a fast assault boat. The TP47 torpedo is a new generation of lightweight torpedo developed by Sweden, powered by batteries, with a minimum speed of 35 knots (approximately 65 kilometers per hour), mainly used for shallow and nearshore operations, attacking underwater and surface targets. Torpedo is an indispensable combat weapon in modern naval warfare, known as the "underwater nemesis" of ships. In recent years, with the support of multiple new technologies, modern torpedoes have evolved from simple program controlled weapons to underwater intelligent nodes for systematic combat. As an important weapon in modern naval warfare, meeting different combat needs, the diverse classification of torpedoes reflects different combat requirements and technical characteristics. The main classification method is based on the diameter of the torpedo body, including micro, light, heavy, and super heavy torpedoes. Light torpedoes generally have a diameter of less than 400 millimeters (mostly 324 millimeters and 350 millimeters), are relatively light in weight, and are mainly carried and thrown by surface ships, helicopters, or fixed wing aircraft to perform anti submarine missions. The MU90 lightweight torpedo jointly developed by France and Italy adopts electric propulsion, has a small size and strong maneuverability, and is suitable for use in shallow waters near the coast. Heavy torpedoes typically have a diameter of 533 millimeters, are larger in size and weight, and have a longer range. They mainly attack submarines and large to medium-sized surface vessels. The American MK48 series torpedoes are a typical long-range heavy anti submarine/anti-ship torpedo. There are also super heavy torpedoes (with a diameter exceeding 650 millimeters) and micro torpedoes, which are respectively used to strike super large targets such as aircraft carriers and perform special shallow water missions. According to different attack targets, the positioning function of torpedoes is also clearly distinguished. Anti ship torpedoes are specifically designed to attack surface ships, with typically larger warheads that aim to cause fatal damage to the ship's structure. Anti submarine torpedoes are specifically designed for "hunting" large underwater targets such as submarines, and require high sensitivity and anti-interference capabilities for their self guidance systems. They can accurately identify and track submarine targets in complex underwater acoustic environments. Multi purpose torpedoes can switch combat modes according to mission requirements, balancing anti submarine and anti-ship missions. In addition, there is also an anti torpedo torpedo. This is a hard kill defense weapon that actively seeks, intercepts, and destroys incoming torpedoes. The power system determines the speed, range, and stealth of torpedoes, and based on this, torpedoes are classified into thermal powered torpedoes and electric powered torpedoes. Thermodynamic torpedoes use fuel combustion to generate power, which has the advantages of fast speed, long range, and high power. However, they produce noise and wake during navigation, and have poor concealment. Electric powered torpedoes are driven by electric energy, with no wake and low noise during navigation. They have the advantages of good concealment and unrestricted depth of navigation; The disadvantage is that the speed is relatively slow, the range is short, and it is greatly restricted by battery technology. In addition, there is a type of rocket assisted torpedo. This is a special weapon that combines torpedoes with rocket (missile) propulsion systems. The torpedoes are quickly delivered by rockets to distant target areas and then re entered into water for attack, greatly expanding the attack range and suitable for anti submarine operations. The guidance system directly determines the positioning accuracy of torpedoes. According to the guidance method, there are self controlled torpedoes, self guided torpedoes, line guided torpedoes, and composite guided torpedoes. The self controlled torpedo adopts program control to navigate according to the preset course. Self guided torpedoes mainly include acoustic guided torpedoes and wake guided torpedoes. Acoustic guided torpedoes use sonar technology to track targets by receiving target noise or by emitting echoes of sound waves; Tailstream guided torpedoes detect targets by detecting the wake generated by surface ships after navigation. The wire guided torpedo is connected to the launch platform through a slender wire and remotely guided by the platform, with strong anti-interference ability. Modern torpedoes often use composite guidance technology, such as first using wire guidance to guide the torpedo to the target area, and then switching to self guided mode for final precision strike, which is currently the mainstream torpedo guidance technology. Aiming at the forefront and exerting multi-directional force, the exploration of torpedo technology mainly focuses on improving the probability of breakthrough, enhancing combat effectiveness, and accelerating system integration. Its cutting-edge breakthroughs focus on three aspects: high-speed penetration of supercavities, intelligent guidance and control, and innovation of integrated power systems. The supercavitating technology can greatly increase the speed of torpedoes and compress the response time of enemy defense systems. This technology generates and maintains a gas cavity around the torpedo body at the torpedo head, reducing resistance and achieving extremely high underwater speeds when the torpedo navigates in water. The new Russian supercavitating torpedo has a speed of 60 knots and a sprint speed of 300 knots during the attack phase. The American ASRock anti submarine missile modified supercavitating torpedo has a speed of over 200 knots. Due to the failure of the sonar system of supercavitating torpedoes during high-speed navigation, inertial navigation combined with pre-set programs is often used for combat, mainly attacking large targets that move in a straight line at low speeds. Intelligent guidance and control enable torpedoes to have higher autonomous decision-making and adaptability to complex environments, especially modern torpedoes commonly adopt a "human in the loop" control mode. With the support of fiber optic or other underwater acoustic links, the operator of the launch platform can receive real-time data returned by torpedoes and issue commands. In addition, the introduction of intelligent algorithms enables torpedoes to accurately identify predetermined targets in complex ocean background noise and multi-target environments through voiceprint library comparison and deep learning, with strong anti-interference capabilities. Some intelligent torpedoes can lurk underwater for a long time, entering an activated state and launching attacks upon receiving specific instructions or being triggered by targets. The innovation of the power system is the key to the evolution of torpedoes into underwater precision guided "killers". With the support of the new power system, the fuel combustion of the thermal power torpedo is more complete, the power is stronger, and the exhaust emissions are less, making the trajectory more concealed. Electric torpedoes rely on high-energy batteries (such as lithium silver oxide seawater batteries) to drive, resulting in extremely low noise during navigation and no visible wake, making them more concealed. With the support of new technological breakthroughs, modern torpedoes have transformed from a single defensive combat weapon to an underwater intelligent node in systematic combat. Becoming a system combat node in regional denial of defense operations, advanced heavy torpedoes carried by submarines are one of the most effective and intimidating means to counter large surface formations. It can force the enemy fleet to invest huge resources in anti submarine defense, effectively enhancing the depth of our own defense. In the context of information warfare, maritime operations particularly emphasize intelligence and autonomous combat capabilities. Torpedoes are not only combat weapons, but also an extension of underwater networks. Submarines can transmit intelligence to other platforms through torpedoes or receive information detected by torpedoes, forming a temporary underwater intelligence network. At the same time, with the help of intelligent algorithms, torpedoes can autonomously identify targets in adversarial environments, select the best attack point, and perform complex tactical attack tasks. Under the concept of systematic warfare, modern torpedoes will further become intelligent combat nodes at sea. It is combined with new platforms such as unmanned underwater vehicles and unmanned surface vessels, and carried forward by unmanned underwater vehicles and unmanned surface vessels to perform diverse tasks such as intelligence, reconnaissance, and strike. The transformation of this underwater combat mode will greatly affect the form of underwater attack and defense, upgrading underwater combat from platform confrontation to system game, and promoting the continuous upgrading of underwater attack and defense operations. (New Society)