The prototype of the "Low Profile Autonomous Vessel" semi submersible unmanned supply vessel participated in the "Fusion Project Vertex 4" joint exercise. Recently, a semi submersible unmanned supply vessel called the "Low Profile Autonomous Vessel" appeared in the US military's "Fusion Project Vertex 4" joint exercise, attracting attention from the outside world. It is reported that this type of unmanned boat adopts a semi submersible fast boat design, mainly used to provide flexible and efficient logistics and weapon supply for the US Marine Corps to carry out "interior line operations" and "island hopping operations" in disputed waters, and enhance the tactical logistics supply capability of the US military in the Asia Pacific region. The US Marine Corps stated that the "low profile autonomous vessel" draws inspiration from the semi submersible speedboat design used by drug traffickers and has been improved based on the combat concept of the US Marine Corps' "Expeditionary Advance Base". In the future, it will develop into the exclusive unmanned supply vessel of the US Marine Corps. According to reports, two prototype "low profile autonomous vessels" have been put into testing. This type of boat is about 21 meters long, 2 meters wide, with a water depth of 1.5 meters and a water surface freeboard of about 30 centimeters. The prototype boat is equipped with two engines and propelled by twin propellers, with a speed exceeding 11 knots; The midship of the hull is equipped with a load compartment, and the stern is equipped with a simple mast, which is used to install communication equipment such as navigation radar and satellite antennas. The boat does not have a crew compartment and is remotely controlled by two operators using handheld controllers. The boat can carry a payload of 1 ton or 2 Navy Strike Missiles (NSMs). In addition to adopting a semi submersible design, this type of boat can also dive more than 1 meter deep underwater for concealed navigation. The US Marine Corps was impressed by the semi submersible speedboat used by drug traffickers during their collaboration with the Coast Guard and DEA to combat drug trafficking groups. This semi submersible speedboat is not only difficult to detect and track, but also has a small tonnage, simple structure, and high cost-effectiveness. It can be widely used as a consumable in war. According to foreign media reports, the US Marine Corps will conduct further tests on this type of unmanned boat in the upcoming joint exercises and will make bulk purchases in the coming years. In recent years, the US Marine Corps has considered adopting unmanned autonomous combat systems in almost all fields and hopes to delegate as many tasks as possible to unmanned autonomous combat systems. To this end, the US Marine Corps is accelerating the development of autonomous equipment such as semi submersible unmanned supply boats to enhance the autonomy of the troops. The senior management of the US Marine Corps believes that unmanned autonomous combat systems that exclude humans have unparalleled advantages in high-end maritime warfare. The unmanned autonomous combat system can not only overcome the physiological and psychological challenges posed by combat environments such as the ocean and sky, but also further expand the combat space and means, making controversial military operations simpler and more efficient, with lower combat costs. Especially in the "Interior Force" combat concept developed by the US Marine Corps, the unmanned autonomous combat system conforms to the combat force description of "small, lethal, low feature, high mobility, and easy maintenance". In the future, it will be deployed in large numbers to the Asia Pacific region to improve wartime transportation efficiency. To this end, the US Marine Corps is accelerating the development of unmanned autonomous transportation platforms at sea. In early 2023, the US Navy received its first unmanned autonomous expeditionary high-speed transfer ship - the Pioneer class Apalachicola. The ship adopts a catamaran design, with a length of 103 meters and a width of 28.5 meters, a full load displacement of 2362 tons, a maximum speed of 45 knots, and a stern cargo hold area of 1800 square meters. The ship is capable of autonomous operation and combat, and is currently the largest unmanned vessel in the United States Navy. It can operate autonomously for up to 30 days without intervention and has a range of approximately 2770 kilometers. It can provide rapid supply to the distributed deployment of the Marine Corps over a large area. It can be foreseen that in the future "island hopping operations" in the Asia Pacific region, the coordinated use of Pioneer class expeditionary high-speed transfer ships and semi submersible unmanned supply boats will become the main mode of tactical logistics supply operations for the US Marine Corps. The core value of supporting the "missile wall" containment strategy for semi submersible unmanned supply vessels lies in their concealed, fast, and inexpensive transport and supply capabilities. This type of boat can carry two "Navy Strike Missiles" and provide rapid firepower and logistical support for the US Marine Corps Expeditionary Anti Ship System in the vast western Pacific Ocean, providing direct and front-line firepower and logistical support for its implementation of the "Missile Wall" strategy, and helping to break through the "last mile of the battlefield". The so-called "missile wall" strategy of the US military is to deploy mobile land-based anti-ship and anti-aircraft missiles on the Asia Pacific island chain to form a firepower advantage. These firepower systems are mainly composed of medium range cruise missile launchers installed on joint light tactical vehicles, carried by Pioneer class expeditionary high-speed transfer ships or transport planes, and flexibly deployed and rapidly evacuated between forward bases and islands in the Asia Pacific region. However, a major challenge facing this strategy is the inability to provide timely ammunition supply. For this purpose, the idea of the US Marine Corps is to use semi submersible unmanned supply boats carrying "Navy Strike Missiles" to dive into the water, covertly cross to designated islands or expeditionary bases, and be transported by the US Marine Corps to the nearest missile launch base in need of supplies, achieving ammunition supply during the "island hopping operation". Although the US Marine Corps has verified the advantages of semi submersible unmanned supply boats through exercises, the practical reference of this non adversarial background test is insufficient. Firstly, this semi submersible unmanned supply vessel with a speed of less than 12 knots is difficult to effectively supply the "island hopping operation" in high adversarial environments. Secondly, due to the lack of defense measures, the probability of semi submersible unmanned supply boats being discovered and sunk during navigation is relatively high, especially in the case of navigation information being blocked and interfered with, which will greatly reduce their combat use. Once again, the survival capability of the US military's wartime sea supply points in the Asia Pacific region is worrying. As a semi submersible unmanned supply vessel that connects the "last mile of the battlefield", it is difficult to complete the closed-loop of ammunition and material supply operations. Its future use remains to be further observed. (New Society)