cryowizard: (Peace Through Superior Firepower)
Submarines could become invisible to sonar 

Scientists at the University of Illinois in the United States have developed and successfully demonstrated a sonic cloak that could make submarines completely invisible to sonar.

The team of scientists, led by mechanical science and engineering professor Nicholas Fang, announced earlier this month that they have produced and demonstrated an acoustic cloak that makes underwater objects invisible to sonar and other ultrasound waves, finally proving what has long been speculated.

“We are not talking about science fiction. We are talking about controlling sound waves by bending and twisting them in a designer space,” Fang said in a statement. “This is certainly not some trick Harry Potter is playing with.”

Rather than absorbing sound waves, the new material bends sound waves around the object, making it appear invisible.

The researchers tested their clock by wrapping it around a steel cylinder and submerging it in a water tank with an ultrasound device on one side and a sensor on the other. The cloaked cylinder did not show up on their equipment and proved invisible to a broad range of sound waves.

They then tried testing objects with different materials and densities, with similar results.

The cloak itself consists of 16 concentric rings of acoustic circuits that channel sound waves. Sound waves vary their speed from the outer rings to the inner ones, becoming faster further inside the rings. Because speeding up requires energy, the sound waves flow around the cloak’s outer rings, guided by channels in the acoustic circuits. The circuits bend the sound waves to wrap them around the outer layers of the cloak.

The metamaterial cloak can cover a wide variety of sound wavelengths, from 40 to 80 kHz, although in theory it could be tuned to cover tens of megahertz. Military sonar systems operate anywhere from 1000 Hz to 500 kHz, according to an Australian government report. This would make submarines covered in the cloak invisible to sonar, as the sound waves pass around the vessel rather than bouncing back to the sonar detector.

"This is not just a single wavelength effect. You don't have an invisible cloak that's showing up just by switching the frequencies slightly," Fang said.

The technology could also be applied to other areas of submarine stealth, such as cavitation, whereby small bubbles form and implode around fast moving objects like propeller blades. Fang and his group believe they could harness their cloak’s properties to balance energy in caviation-causing areas. Thus, the cloak could be used to keep noise from getting out of a submarine in addition to stopping sonar waves from bouncing back to their source.

via DefPro
cryowizard: (Default)
Popcorn, anyone?

A design flaw in Britain's nuclear arsenal means that warheads could set off a chain reaction "like popcorn" if they were accidentally dropped, according to Ministry of Defence docuuments. More than 1,700 warheads are affected by the problem which would cause them to explode one after another, an effect known as "popcorning."

A typical Trident nuclear missile contains three to six warheads, and some submarines carry up to 24 missiles, meaning the potential for disaster could be huge.

We don't need the Brits any more, do we?
cryowizard: (Default)
From a submarine blog:
Those of us who left active duty before the year 2000 probably missed this sonar tidbit. Although the concept sounds goofy, it is supported well enough in scientific communities to assure winning your next beer bet.

From the start of WWII, researchers studied snapping shrimp. As any submariner knows and many heard firsthand, these "biologicals" create loud, underwater noise. Colonies produce such a din that during World War II, the constant crackling from these shrimp sometimes foiled the military's attempts to find enemy subs.

For years, the assumption had been that the cracking sound occured when the moving part of the shrimp's claw struck its stationary opposite, like castanets. Instead, cavitation -- the mechanical process which plagues ships' propellers--is to blame. Cavitation occurs when liquid is forced to move above a certain speed and, as a result, experiences a pressure drop (known as Bernoulli's principle). This phenomenon causes tiny air bubbles in the fluid to swell. As the fluid slows and the pressure again rises, the imploding bubbles generate a shock wave with audible sound.

The little ol' shrimp communicate with one another, defend their territory, and stun their prey with this sound.

For doubters: here, here and you more scientific folk will like the link here.
cryowizard: (Default)
Google Maps coverage of the New London Submarine Base in Connecticut.

Top Secret )

Look at that thing inside the dock! It's huge, even compared with two subs above it.

It has to be an Ohio-class boomer...
cryowizard: (Default)
117 successful launches in a row. Not too shabby.
CAPE CANAVERAL: The U.S. Navy conducted a successful test launch Nov. 21 of two Trident II D5 Fleet Ballistic Missiles (FBMs) built by Lockheed Martin. The Navy launched the unarmed missiles from USS Maryland (SSBN 738) at the Eastern Range in the Atlantic Ocean.

With this two-missile mission, the Trident II D5 missile has achieved 117 consecutive successful test launches since 1989 -- a record unmatched by any other large ballistic missile or space launch vehicle. The launches are part a continuing series of operational system evaluation tests conducted by the Navy to assure the safety, reliability, readiness and performance of the Trident II D5 Strategic Weapon System, as required by the Department of Defense's National Command Authority and conducted under the testing guidelines of the Joint Chiefs of Staff.
First deployed in 1990 and scheduled for deployment until 2042, the Trident II D5 is aboard 12 of an eventual 14 Trident II-configured Ohio-class submarines. The three-stage, solid propellant, inertial-guided ballistic missile has a range of 4,000 nautical miles and carries multiple independently targeted reentry vehicles.

From DefenceTalk
cryowizard: (Default)
Ouch, ouch and ouch again. I wonder if anybody's going to lose their commission because of this. Very embarrassing.
A Chinese submarine stalked a U.S. aircraft carrier battle group in the Pacific last month and surfaced within firing range of its torpedoes and missiles before being detected.


According to the defense officials, the Chinese Song-class diesel-powered attack submarine shadowed the Kitty Hawk undetected and surfaced within five miles of the carrier Oct. 26.

The surfaced submarine was spotted by a routine surveillance flight by one of the carrier group's planes.

The Kitty Hawk battle group includes an attack submarine and anti-submarine helicopters that are charged with protecting the warships from submarine attack.

According to the officials, the submarine is equipped with Russian-made wake-homing torpedoes and anti-ship cruise missiles.

UPD: a lot of discussion, some opinions are interesting:
cryowizard: (Default)
Любителям и ценителям атомных подводных лодок, как российских, так и американских.

Неплохая книга/набор статей.

В общем, как почитаешь, так видно, что наши, при всех хороших ТТХ лодок, всё равно уступали по живучести из-за "технических недоработок", "ускоренной" постройки, а самое главное, из-за плохого обучения экипажей тому, что в Штатах называется damage control. Чётко прослеживается традиционное пренебрежение Советского командования и правительства к человеческой жизни.

Статьи про К-19, прозванную "Хиросимой", про "Комсомолец" -- жуткие истории, а по сравнению с Чажмой Чернобыль -- чепуха собачья...
cryowizard: (Default)
Сижу, читаю справку про стратегические ракеты подводного базирования Trident II (D5). Тут натыкаюсь на вот такое и о@*еваю:
As a first step, the specialised Submarine Command System (SMCS) which was originally developed for the UK's Vanguard submarines, is being converted to a new version called SMCS-NG which runs on the Microsoft Windows operating system. This is probably the first use of Microsoft Windows to command a militry platform whose purpose is the firing of intercontinental nuclear missiles.

Дайте две!!
cryowizard: (Default)


Краткая справка:

Aтомный подводный ракетоносец проэкта 941, классификация НАТО "Тайфун". Производится в Северодвинске. Самая большая подводная лодка в мире. В полном вооружении несёт 20 баллистических ракет РСМ-52, по 10 разделяющихся ядерных боеголовок мощностью 100кТ на каждой.
cryowizard: (Default)
The only documented use of a nuclear submarine in anger took place during the 1982 Falklands conflict between Britain and Argentina.

On May 1, 1982 nuclear submarine HMS Conqueror sighted Argentinian cruiser General Belgrano and two of its Exocet-equipped destroyer escorts. The Royal Navy Task Force considered the group a threat and on May 2 the War Cabinet cleared HMS Conqueror to remove General Belgrano from the theater. The Conqueror fired torpedoes from 2000 yards, scoring two hits and sinking the Argentinian cruiser. Subsequent depth charge attacks on the Conqueror by the cruiser's escort were unsuccessful.
cryowizard: (Default)
Q: Who holds the record as the longest serving active duty military officer in the history of US Armed Forces?

A: Admiral Hyman G Rickover, "father of the nuclear fleet", with 64 continuous years in the US Navy

I personally admire the man whose singular vision literally forced creation of the US Nuclear Navy culminating with the launching of the first nuclear submarine SSN 571 "Nautilus". For a first-generation Jewish immigrant he made an astonishing career. He a was a tough son of a bitch, people were scared shitless of him, but he had a vision for using nuclear propulsion and employed everything in the arsenal to see that vision implemented. His brash style and absolute contempt for bureaucracy pretty much guaranteed him loads and loads of loyal enemies within US Department of Defence, ultimately resulting in him being forced into retirement by President Reagan in 1982. In 1984, two years prior to his death, a Los Angeles-class attack sub (SSN-709) was named after him, one of only 9 vessels in the US Navy to be named after a living person. Rickover died in 1986.

It was interesting, and shocking to me, to find out that closer to the end of his career Rickover said that given the choice, he'd "sink them all".

From Wiki:

Given Rickover's single-minded focus on naval nuclear propulsion, design and operations, it came as a surprise to many when near the end of his career he testified before the U.S. Congress that, were it up to him, he "would sink them all." A seemingly outrageous enigma of a statement -- and perhaps one attributable to an old man beyond his time -- in context Rickover's personal integrity and honesty were such that he was lamenting the need for such war machines in the modern world, and specifically acknowledged as well that the employment of nuclear energy ran counter to the course of nature over time.

Personal quotes from WikiQuote :

"At any moment during a twenty-four-hour day, only one-third of the people in the world are asleep. The other two-thirds are awake and creating problems."

"Good ideas are not adopted automatically. They must be driven into practice with courageous patience."

"Great minds discuss ideas, average minds discuss events, small minds discuss people."

cryowizard: (Default)
US Navy humour:

Q: On an Ohio-class strategic missile submarine carrying 24 Trident D5's, what is the compartment housing missile tubes called?

A: "Sherwood Forest"


cryowizard: (Default)

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