The modern submarine has gone through more than 100 years of history since its birth in the early 20th century, and it has played a huge role in the long years and has undergone many changes in itself. From the "Holland-6", "XXI type", "Nautilus" to "typhoon" class, leaving a monument to look up to.
Most of today's submarines, especially nuclear submarines, are slender and streamlined. The bow is round and round like a spindle, the hull is curved everywhere, and the tip of the stern tip gradually tapers from the middle to the back, like a drop of elongated water. Or add some trapezoidal superstructures and parallel mediators, becoming a popular "cigar type".
Epoch-making "Holland 6"
But this was not the case with World War II-era submarines, which had a bow curved bow, a flat stern, a propeller in front of the rudder, and a buoyant water tank on the bow, which looked a lot like a surface warship from the side. Such a shape is suitable for surface navigation, which can reduce the resistance of Xingbo and improve the maneuverability of the surface, the surface speed is more than a dozen knots, and the underwater speed is only four to five knots.
Early German U-boats, conventional linear types like boats
In fact, early submarines also tried to streamline the shape, in order to improve the underwater speed, people designed the hull to spindle shape to reduce drag.
However, at that time, the technology was limited, and it was difficult to solve the problem of submarine underwater maneuvering. Coupled with the fact that military ideology cannot keep up with technological development, people have not yet realized the true power of the submarine, and only use it as an auxiliary ship of surface ships, as a "torpedo boat that can dive".
1878 "Risugan" 2 spindle submarine
Therefore, engineers from all over the world worked hard to improve the surface performance of submarines, most of the time on the surface of the water, until the operation of the underwater, until the middle and late stages of World War II.
But by 1943 the situation had changed, and as the amount of Allied anti-potential had increased rapidly, the once-arrogant and crazy German "wolves" had become fish on the chopping block, and life was getting harder and harder every day.
The once unimpeded surface of the water is now a shura field, and submarines have to hide more and more underwater. Therefore, Germany stepped up the development of submarines based on underwater navigation, which gave birth to the XXI type, XXIII type and other true "submarine" originators.
Type XXI, the real "submarine"
After the rapid development of science and technology after World War II, countries have carried out large-scale research on the underwater navigation performance of submarines. In 1948, Rear Admiral Momson, deputy commander of the U.S. Navy's Submarine Warfare Unit, proposed the construction of a new submarine with optimal underwater performance, and the military leadership then asked the Naval Ship Bureau to conduct related research.
The designers conducted a lot of hydrodynamic studies, did a lot of experiments in the David Taylor test pool, and finally found the hull linear type with the least underwater high speed resistance - the teardrop shape. This was the beginning of the birth of the "Big Blue Fish" submarine.
Construction of the AGSS-569 submarine began in March 1952 at the Portsmouth Naval Shipyard in New Hampshire, and was launched in August 1953 as a vital underwater experimental platform.
In 1953, the Big Blue Croaker
It was the first submarine to adopt a teardrop-type shell, with a total length of 62.2 meters, a width of 8.2 meters, a draft of 5.6 meters, a standard displacement of 1242 tons, and an underwater displacement of 1837 tons. The hull adopts a double-hull structure, all cross-sections are approximately circular, and the pressure-resistant shell is made of the newly developed HY-80 low-carbon high-strength steel.
After the "Big Blue Croaker" entered service, the US military could not wait to carry out experiments, and tested a variety of subjects in 5 stages, and made many modifications inside and outside the submarine.
The first phase of experiments began in 1954, testing the shape of the symmetrical slewing hull, the high-strength steel properties of hy-80, the multi-purpose antenna, and an aircraft joystick-like maneuver.
Experimental results proved that the new high-strength steel is fully applicable on submarines without any adverse consequences, and later promoted in large quantities on new submarines together with multi-purpose antennas.
In December 1955, the "Big Mackerel" underwent the first modification, the propeller was moved to the rear of all rudder surfaces, and the stern elevator and rudder were arranged in a cross shape, which was very different from the previous oar arrangement in front of the rudder.
In the second phase of the experiment in 1956, this new arrangement achieved good results, forming the common submarine stern shape today.
Common cross-shaped stern rudder
The experiment also tested digital multi-beam scanning sonar, which detects weak acoustic signals in all directions underwater, and later developed into advanced BQR series sonar systems.
In the third phase of the experiment in 1959, the "Big Mackerel" was equipped with an X-shaped stern rudder.
Experiments proved that this rudder had many advantages, but considering safety and reliability, the U.S. Navy did not adopt it in the end. However, Sweden, the Netherlands and other countries have been inspired by this, and have been improved and installed on their own conventional power submarines to develop a fashionable rudder scheme.
X-shaped rudder of the big mackerel
In order to carry out underwater high-speed slewing experiments, the designers installed a control surface called "ridge rudder" behind the shell of the command platform, which can swing like the dorsal fin of a fish, hoping to enhance the balance and prevent the submarine from tumbling when it makes sharp underwater turns.
A ring of submersible brakes was also installed at the rear of the hull, and a B-47 bomber's parachute was installed behind the shell of the podium to help the submarine decelerate underwater and lift the bow upwards. But these methods are not ideal, the simplest and most effective is to float the submarine through the bow elevator.
The experiment also tested new active/passive sonar and towed sonar arrays, equipped for later use in nuclear submarines.
In 1965, the "Big Mackerel" entered the fourth phase of experiments, the Navy installed a high-capacity silver-zinc battery in the boat, the propulsion motor power increased to 7500 shaft horsepower, and the single propeller was replaced by a double reverse propeller. Due to the lack of silver, the Navy even borrowed a lot of silver ingots from the mint, and it is not known whether it was returned later.
In the experiment, the "Big Blue Croaker" soared to 33 knots in one breath underwater, setting a record for the highest underwater speed of conventionally powered submarines. The designers also tested two spindles of different lengths to study the effect of the longitudinal distance of the propeller from the hull on propulsion efficiency.
In 1968, the Big Mackerel underwent two more modifications in Portsmouth, including a propulsion system and new electronics, and was extensively tested in the fifth phase of experiments. But the test results have been kept highly confidential and have not been declassified to this day.
After five stages of experimental testing, the US military obtained a large amount of precious data from it, laying a solid foundation for the development of nuclear submarines later.
Soviet "Alpha" class teardrop shape
The Navy had intended to conduct a phase VI test, but was stranded due to a lack of funding. The "Big Blue Croaker" also needs to be repaired due to aging equipment, and the main engine is also damaged, and the military can only temporarily seal it. And the wind talks about originality, and plagiarism is prohibited.
These experiments on the "Big Blue Fish" had a profound impact on the submarines of later generations, and the perfect combination of teardrop hull and nuclear power pushed the nuclear submarine to the top of the list of horror tycoons.
On its basis, the United States built the droplet-type "Bonito" class attack nuclear submarine and formed the world's first underwater high-speed nuclear submarine fleet.
Bonito-class attack nuclear submarine
If the "Nautilus" has created a vast world of nuclear-powered submarines, then the "Big Blue Fish" is the promoter of the underwater high-speed era, and it is called a milestone in the history of submarine development with epoch-making significance.
The Mackerel was mothballed for many years until it was officially retired in 1972. The U.S. Navy converted it into a museum and parked it in Portsmouth, the birthplace of portsmouth, to commemorate the submarine, which made an outstanding contribution to the history of submarine development.