#1 "Almost Like a Nuclear Submarine" 2 Weeks Underwater
09-10-2011, 10:51 AM
- Join Date
- Aug 2005
The new submarines have a dramatically different capability from the existing ones in terms of their propulsion systems,” a security official tells IsraelDefense.
This comes on the heels of recent publications about Israel and Germany agreeing to the construction of a sixth submarine for the Israeli navy’s fleet of three active submarines.
The reports say the deal was almost closed, during German Defense Minister Thomas de Maizière’s last visit to Israel. A previous contract, following the Second Lebanon War, was between Israel and two German companies-Howaldtswerke-Deutsche Werft of the city of Kiel and Thyssen Nordseewerke of the city of Emden—for the construction of two additional Dolphin submarines. The navy expects these vessels will be delivered by 2013-2014.
According to international sources, the submarines provide a second-strike capability. The upgraded Dolphin will be able to remain underwater for weeks—longer than the maximum submersion time of the submarines currently in the navy’s service.
The Dolphins, based on the German A212 submarine, weigh 1,900 tons and equipped with ten launchers for torpedo missiles. Reports also claim that Israel has modified the Dolphin’s 650mm torpedo to launch cruise missiles with nuclear warheads.
Air-independent propulsion (AIP) is a term that encompasses technologies which allow a submarine to operate without the need to surface or use a snorkel to access atmospheric oxygen. The term usually excludes the use of nuclear power, and describes augmenting or replacing the diesel-electric propulsion system of non-nuclear vessels. The United States Navy uses the hull classification symbol "SSP" to designate boats powered by AIP, while retaining "SS" for classic diesel-electric attack submarines.
AIP is usually implemented as an auxiliary source. Most such systems generate electricity which in turn drives an electric motor for propulsion or recharging the boat's batteries. The submarine's electrical system is also used for providing "hotel services"—ventilation, lighting, heating etc.—although this consumes a small amount of power compared to that required for propulsion.
Torpedo Tube Launched Tomahawk Cruise Missiles
BGM-109A Tomahawk Land Attack Missile - Nuclear (TLAM-A) TTL with a W80 nuclear warhead.
Operational range........Block III TLAM-C, Block IV TLAM-E - 900 nmi (1,000 mi; 1,700 km) Block III TLAM-D - 700 nmi (810 mi; 1,300 km)
W80 (nuclear warhead)
The W80 is a small thermonuclear warhead (fusion weapon) in the enduring stockpile with a variable yield of between 5 and 150 kt of TNT.......It was designed for deployment on cruise missiles and is the warhead used in the majority of nuclear-armed US Air Force ALCM and ACM missiles, and their US Navy counterpart, the BGM-109 Tomahawk...... It is essentially a modification of the widely deployed B61 weapon, which forms the basis of most of the current US stockpile. The very similar W84 warhead was used on the BGM-109G Gryphon GLCM.
Nuclear weapons and Israel
It is believed that Israel had possessed an operational nuclear weapons capability by 1967, with the mass production of nuclear warheads occurring after the Six-Day War....Although no official statistics exist, it has been estimated that Israel possesses from 75 to as many as 400 nuclear weapons, which are reported to include thermonuclear weapons in the megaton range. Israel is also reported to possess a wide range of different systems, including neutron bombs, tactical nuclear weapons, and suitcase nukes....Israel is believed to manufacture its nuclear weapons at the Negev Nuclear Research Center, a highly secretive nuclear installation located near Dimona.
Delivery mechanisms include Jericho intercontinental ballistic missiles, with a range of 11,500 km, and which are believed to provide a second-strike option. Israel's nuclear-capable ballistic missiles are believed to be buried so far underground that they would survive a nuclear attack.Additionally, Israel is believed to have an offshore nuclear second-strike capability, using submarine launched nuclear-capable cruise missiles, which can be launched from the Israeli Navy's Dolphin-class submarines.
09-10-2011, 01:16 PM
- Join Date
- Mar 2010
I got interested in this Air Independent Propulsion and started searching around. Evidently, they are talking about things like fuel cell technology where the main source of surface propulsion is diesel. The diesel is used to get to the designated cruising area, and then fuel cell engines get them around underwater.
Can't find where the U.S. has commissioned any SSP boats, but Germany has, and so has Greece. I can see where it makes sense for Israel because they wouldn't go searching around the world like the U.S. does.
Interesting concept for North Korea, also.
Anyone know anything else about these types?
09-10-2011, 01:56 PM
- Join Date
- Aug 2005
AIP - The Early History
The original designs used hydrogen peroxide (H2O2) In Walter's system.. hydrogen peroxide is highly unstable and prone to explosions..For their Initial Experiments in AIP The Germans used T-Stoff - Rocket Fuel comprising 80% hydrogen peroxide plus oxyquinoline or phosphate as a stabilizer and Z-Stoff - Water solution of Na (Natrium) and Potassium Permanganate (kaliumpermaganat) to produce steam for the turbine and fresh oxygen ..
Despite their initial successes, submarine pioneers were still eager to find some means to free their boats from the necessity of surfacing frequently for access to the atmospheric oxygen demanded by the gasoline or diesel engines that charged the batteries. A number of approaches were tried, but eventually, open-cycle diesel engines, lead-acid batteries, and electric motors for submerged propulsion became the standard submarine engineering plant that served well through two world wars.
In the early 1930s, however, a brilliant German engineer, Dr. Helmuth Walter (ca. 1900-1980) of Kiel's Germaniawerft, proposed a radical new submarine propulsion plant based on the use of high-purity hydrogen peroxide (H2O2) as an oxidant. In Walter's system, hydrogen peroxide from an onboard supply was decomposed using a permanganate catalyst to yield high temperature steam and free oxygen. Into the reaction chamber was injected diesel fuel, which combusted with the oxygen to yield a mixture of steam and hot gas that drove a high-speed turbine. The exhaust and condensed steam were then expelled overboard. Walter's primary design goal was high underwater speed, rather than long endurance, and indeed, his first submarine prototype, the experimental V80, reached 28.1 knots submerged in its 1940 trials - at a time when conventional submarines were limited to 10 knots or less. Thus, V80, only 76 tons and 22 meters long, also served as an early test bed for studying the dynamics and control of high-speed underwater vehicles.
....Todays AIP Uses Fuel Cells pumped by hydrogen and oxygen gas combined to produce electric current and fresh water..
In simplest terms, a fuel cell is an electrochemical conversion device that combines hydrogen and oxygen to produce water, electricity, and heat. Fuel cells are already seeing a number of promising applications in the space and automotive industries, and many authorities believe that fuel cells offer the best potential for developing more capable AIP systems in the future. There are several alternative configurations, but for submarine propulsion, so-called "Polymer Electrolyte Membrane" (PEM) fuel cells have attracted the most attention because of their low operating temperatures (80° Centigrade) and relatively little waste heat. In a PEM device, pressurized hydrogen gas (H2) enters the cell on the
Diagram of a Fuel Cell; Caption follows. In a typical fuel cell, gaseous hydrogen and oxygen are combined catalytically to produce water, heat, and useful electricity. Already successful in the U.S. space program, fuel cells are seeing increasing use as submarine power sources.
The anode side, where a platinum catalyst decomposes each pair of molecules into four H+ ions and four free electrons. The electrons depart the anode into the external circuit - the load - as an electric current. Meanwhile, on the cathode side, each oxygen molecule (O2) is catalytically dissociated into separate atoms, using the electrons flowing back from the external circuit to complete their outer electron "shells." The polymer membrane that separates anode and cathode is impervious to electrons, but allows the positively-charged H+ ions to migrate through the cell toward the negatively charged cathode, where they combine with the oxygen atoms to form water. Thus, the overall reaction can be represented as 2H2 + O2 => 2H2O, and a major advantage of the fuel-cell approach is that the only "exhaust" product is pure water. Since a single fuel cell generates only about 0.7 volts DC (direct current), groups of cells are "stacked" together in series to produce a larger and more useful output. The stacks can also be arrayed in parallel to increase the amount of current available.
The greatest challenge for fuel-cell AIP systems lies in storing the reactants. Although oxygen can be handled with relative safety as LOX, storing hydrogen onboard as a liquid or high-pressure gas is very dangerous. One solution is to carry the hydrogen in metal hydride accumulators, at low pressure and ambient sea temperature. (A metal hydride is a solid compound of hydrogen and metallic alloy, in which individual hydrogen atoms occupy interstitial positions in the host metal's crystalline lattice. By manipulating temperature and pressure, hydrogen gas can be absorbed or released at will.) Another, less efficient, approach is to generate gaseous hydrogen from a stored liquid hydrocarbon such as diesel fuel, kerosene, or methanol. This requires an auxiliary device called a "reformer," in which a mixture of hydrocarbon and water is vaporized and superheated under pressure to yield a mixture of hydrogen and carbon dioxide.
They have long endurance underwater and allow the sub to remain hidden in enemy waters.When moving they are extremely quiet at speeds below ten knots..
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