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Submarines
Submarines are naval craft that can operate for an extended period of time underwater. They are used primarily as warships, as well as for business, scientific and other purposes. Submarines are different from submersibles, which only have limited underwater capability.
2,056 Questions
How does a submarine move sideways?
Modern submarines have a deployable motor/propeller that can be used to move sideways if necessary. It's not used very often since most boats are moored using 2 or 3 tugs, and it's not that powerful to begin with.
Form of sonar used to detect and locate enemy submarines by means of ultrasonic waves?
Type your answer here... ASDIC
How fast can nuclear submarines go?
The fastest known nuclear submarine to date was the Russian ALFA class (NATO reporting name) submarine. Its design featured a lead-bismuth cooled reactor, enabling the reactor to be much smaller and powerful, making the boat design more streamlined and capable of reaching higher speeds. Its top sustained submerged speed was 41-42 knots, with speed burst capabilities of between 43 and 45 knots. I could reach top speed within a minute.
Most boats can only maintain between 12-15 knots on the surface - this is because modern submarine designs are to allow them to travel much faster underwater than on the surface. The average for most boats is between 25 - 35 knots submerged, depending on class and screw configuration.
Modern submarines are designed to go much faster underwater than on the surface - typically, top speed on the surface is around 17 knots for most boats.
How many countries had submarines in world war 2?
the Americans, Germans and japenese, british and the french had some. the french eventually scuttled their whole fleet, surface and sub, when it was apparent they would be defeated.
What does rov submarine stand for?
ROV stands for "Remote Operated Vehicle". ROV's are not submarines by definition, since they are robots controlled by tether, by an operator stationed on a support vessel.
Who is faster submarines or submersible?
A submarine is way faster. Submersibles have very small electric motors and are usually placed into the sea from their 'mother ship' very close to whatever they are going to work on or survey. In this way they can reduce moving around a lot. Many submersibles do tasks underwater such as hooking up cables, repairing oil well equipment or searching for something. There is no need for them to be fast or to move very far except down and up, ( and they don't use motors for that )
All submarines have specific design limits based on their overall hull construction material and shape. In general, the smaller, more compact, and spherical a submarine is, the deeper it can go, but that's not always the case. Hull material is a big factor as well. Most submarines today are built with steel which has elastic properties, i.e., it can contract and expand with sea pressure many times without hull degradation. By contrast, a Titanium hull (e.g., a Russian ALFA) may be able to go deeper, but the properties of Titanium make it brittle when exposed to extreme pressure over time. Think of a the difference between squeezing a tennis ball repeatedly, and an egg - the egg will begin to crack well before the ball ever will.
The other main reason is that at deeper depths, it doesn't take much damage to the hull to cause a major casualty. At the massive pressure of deep ocean depths, even minor damage can result in catastrophic flooding and failure. You don't need a submarine that can go to deep depths - all you need is a weapon that can go to deep depths.
When was the first US submarine Turtle used?
The Turtle was used during the American Revolution, while the fighting for New York City was taking place. The Turtle's one-man, volunteer crew was Sergeant Ezra Lee from Washington's Continental Army. He made his first attempt to attack the HMS Eagle on September 7, 1776. The Turtle's method of attack was to maneuver beneath its intended target and drill into its bottom, then detach an explosive charge from the outside of the Turtle, which would hang from a chain drilled into the enemy ship and explode with a time fuse. The drill, like the submarine's propulsion, was hand-cranked. The Turtle was thwarted on this attempt because the HMS Eagle's bottom was sheathed in copper sheets, as a protection against tropical boring worms and barnacles. The Turtle's drill could get no "bite" against the copper sheets. In 1777 Lee and the Turtle tried again but this time failed to sink the HMS Cerberus.
In WWII & Korea, submarines used Radar primarily for search operations - ships, surfaced submarines, and especially planes, which were a major threat. Long range detection of an incoming plane allowed the boat to dive to a safe depth and avoid being detected and attacked. They also used it for navigation close to shore.
Modern submarines today use Radar for surfaced navigational operations, typically when transiting from port to their dive point, or from their surface point to the port they're going to. This is primarily for surface ship detection, but in the case of entering a military port, it's for surfaced submarine detection as well. Modern submarines transmit few active signals even when entering port, and those are usually short-range civilian signals (VHF, etc.). Radar is also used in conjunction with GPS and other systems to gain a precise navigational fix when close to shore regardless of weather. No single system is ever relied on for anything onboard a submarine.
Submarines are not easy to see in the water, even surfaced, due to their low cross-section and color (black for most of the time, but their are camouflage paint patterns that can be applied as well in certain circumstances). Surfaced transit during the night require that submarines use a flashing yellow beacon atop one of the masts to denote to other ships that a surfaced submarine is in the area. Having done many small-boat transfers at night on a black submarine deck, I can honestly say it's impossible to see anything of the hull in the dark, and even barely with the light flashing, not to mention what it's like trying to work in pitch-black conditions when you can't see your feet and the deck.
As such, it is important that the crew know exactly what surface ships are where, and their range, so that proper action can be taken to avoid collision. When the boat nears the port it's heading for, Radar is used for establishing precise fixes to compare with GPS, charts, and other systems. Remember that most submarines are nuclear-powered - while the threat of collision when surfaced isn't that high, the problem of running aground is, especially if you're entering an unfamiliar port. Such an occurrence usually results in the relief of Commanding Officer.
How does a diesel submarine recharge its batteries?
World War II submarines were powered by large electric motors. On the surface, the motors drew their power from diesel generators, not unlike how a diesel locomotive operates today. When submerged, the diesel engines could not be operated, and the motors drew their power from huge banks of electric batteries. After the batteries were drained of their power, the submarine would have to surface in order to run its diesel generators to provide propulsion and electric power to the submarine. During this period, the sub's batteries were recharged. Toward the end of World War II the submarine snorkel was invented, which gave a submarine the capability of running its diesel engines while submerged. The submarine was required to stay relatively close to the surface, but it was fully submerged with the exception of the snorkel mast.
Nuclear powered submarines also have banks of electric batteries, but they are only used when the main propulsion plant and/or its steam-powered electric generators are disabled. When a nuclear-powered submarine's batteries are fully drained, they are recharged by the boat's diesel generator if its steam-powered electric generators are not available, or by the steam-powered electric generators when they becomes available. Just like a diesel-electric submarine, a nuclear-powered submarine must operate its diesel generator on or near the ocean's surface.
Most of the unrestricted submarine warfare occurred?
UN-Restricted sub warfare was conducted in both WWI & WWII, & in all oceans & by all major combatants (US, Japan, Germany, Britain, Russia, etc.): Atlantic Ocean, Pacific Ocean, Indian Ocean, etc.
Un-restricted sub warfare simply meant, "not giving prior warning to the vessel to be sunk."
How can ships use ultrasound to detect the depth of water beneath them?
Submarines use standard fathometers, though they're more powerful and more focused than most commercially available units, for depth measurement. The actual frequency used is classified, but it's in the upper Kilohertz range and short pulsed to minimize detection when used during submerged operations close to shore. Anything above 20khz is considered ultrasound.
In the deep ocean they're typically not used, as most boats rely on navigational charts for depth estimates. Most areas of the oceans are deeper than design limits of submarines anyway, so they're rarely used in deep water unless you need to verify a chart depth.
Where might a submarine explore new areas?
Submarines can be manned or robotic submersibles. In the undersea universe they can be used to explore the deepest points on Earth such as the Marianna Trenches. Within the Solar System the possibility of using robotic submarines may allow us to explore the Europa's under ice ocean.
What does the term or acronym SEALOL mean in respect to the British Navy Submarines?
SEALOL is the brand name for a group of industrial seals used on both RN and US submarines. Originally patented and manufactured for years by EG&G in Warwick, RI, the company sold the business to the John Crane company.
Seals of every type are used in many areas aboard submarines, from compressors to water seals, hydraulics, etc. There are few systems aboard a submarine that don't require some type of seal.
The original Patent description for the SEALOL seal is linked below.
How long does it take to make a submarine?
The US Gato class sub could be built in less than 9 months.
Why were submarines significant in World War 1?
Submarines were significant in World War I because they inflicted a lot of damage on shipping around Britain. They sank both military ships, supply ships, and anything else, which brought out the term unrestricted submarine warfare. To site a single example, the U-9 sunk three British cruisers within an hour. We also saw the strategy of the convoy appear in defense. The other significance of submarine warfare in World War I is that the capability of the submarine was clearly demonstrated, and the strategy and tactics (as well as the technology) was developed even further. World War II submarine activity was an extension of the lessons provided in the first war.
The term "Boat" used to reference Submarines goes back to the very earliest submarine designs. A "Boat" is a term used for a vessel launched from a Ship; Submarines were first designed during the days of wooden sailing vessels, and were launched like any other boat from the ship.
Though the official U.S. Navy designation for a submarine ("SS", for Submersible Ship) goes back to the days when submarines were surface vessels (Ships) that had limited submerged operational capability, submariners have always referred to them as "Boats". Even today, 20 years after leaving the Submarine Force, I still get irritated when someone refers to a submarine as anything other than a Boat.
Today's submarines are true submersibles - their operational capability is limited only by their crews (still need food, even if everything else is taken care of). Even modern Diesel Electric submarines, who in WW2 could only stay submerged for hours, can now remain submerged for weeks.
The other major difference that changed the submarine was the switch to a hull design that favored submerged operations. The old WWI and WWII boats were much faster on the surface than submerged. In contrast, today's boats are much faster submerged than they are on the surface.
How can submarines float and sink?
Submarines change their depth by use of ballast tanks. To dive, they open their tanks so that they become filled with water. They also angle their dive planes. To surface, they pump the water out of their tanks and fill them with pressurised air.
How do submarines float and dive?
Sinking a Submarine (or any other vessel) is pretty easy - with enough water it'll sink straight to the bottom of the ocean real fast. The key is getting the number of surfaces to equal the number of dives.
Submarines use several systems along with fixed ballast to decrease buoyancy to submerge, or increase it to surface:
1. Main Ballast Tanks (MBT's)
2. Trim Ballast Tanks (Trim Tanks)
3. Trim/Dive Planes
4. Main Propulsion Systems
Like all vessels, submarines have fixed and variable ballast weight. Her fixed ballast, essentially just iron weights, allow the boat to remain on the surface in a positive buoyancy state, i.e., floating on the surface but mostly submerged. All pictures you see of surfaced submarines only show about a 1/4 of the actual hull above water. Variable ballast, consisting of Main and Trim Ballast tanks, as well as personnel and all supplies onboard, help the boat maintain submerged operations at fixed or variable depths as required.
A boat's fixed ballast weight is a known variable; it is the addition or removal of variable ballast that must be closely monitored. All supplies and personnel (including weapons load-out) are monitored and estimated weight is calculated so that when the MBT's are purged and filled, the crew already knows how much trim ballast water to bring in to achieve a state of Neutral Buoyancy, which is a submerged state in which the boat neither rises nor sinks. Achieving Neutral Buoyancy is also used by Scuba Divers for maintaining their own depth control.
Without knowing an estimate of pre-submergence ballast amount, too much variable ballast can sink her too far upon submerging. If you're wondering, the boat's crush depth or the bottom of the ocean is considered too far, whichever comes first.
The calculations must be continually updated during longer missions, as supplies are used and trash is put overboard via the trash tube, or exercise weapons are shot.
For anyone who is certified in SCUBA, the principles are essentially the same. A diver, using a combination of personal weight and added lead weights for fixed ballast, uses air inflated into, or deflated from, a buoyancy compensator (variable ballast) to adjust for neutral, positive, or negative buoyancy. The only difference is that divers initially make themselves negatively buoyant to get beneath the water.
Water temperature and salinity are also variables and affect variable ballast. For example, due to the cold freshwater ice of the Polar ice cap, water in the Arctic has a lower salinity level than the open ocean. Since colder temperatures affect density, and lower salinity causes less buoyancy, submerged operations under the ice must take this into account for ballasting purposes.
The Main Ballast Tanks are nothing more than large sections between the outer hull and inner hull. Submarines have 2 hulls, much like a thermos bottle; the outer Superstructure which is visible, and the inner Pressure hull, which houses the crew. The bottom of a tank has an open grate, where the top of the tank has a hydraulically activated valve. Think about a bottle without a bottom and a cork in it; if you put it in water and pull the cork the air is forced out by the water pressure - same principle. The pressure on the air inside the tank when surfaced is enormous - to dive the boat, the MBT valves are opened, and the sea pressure forces the air out of the tank through the open valve. Once the tanks are full of water, the valves are closed. As with all onboard systems, the MBT valves, which are physically located on the main deck of the Superstructure, can be opened or closed hydraulically or manually.
After submerging, the Chief of the Watch (the primary operator of the key diving and control systems for the boat) will bring in or pump out water from several Trim Ballast Tanks (used for ship leveling and minor ballast adjustments as the boat moves to specific depths) on the boat. Trimming the boat gets the boat to Neutral Buoyancy. The Chief of the Watch takes orders from the Diving Officer, who is in charge of keeping the boat at NB while submerged. The Diving Officer also gives orders to the Helmsman and Planesman (Helmsman steers, Planesman maintains depth) as necessary, and the Trim/Dive planes and ship propulsion help maintain the boat on depth until the Trim tanks can be adjusted to the new depth, if required.
From there the Dive Planes take over for moving deep or shallow. Older WW2 era submarines used Bow Dive Planes, which were located at the bow of the boat. When the Teardrop Hull shape used today was developed, the Dive Planes were moved to the Fairwater, which is the superstructure above the hull that houses the periscopes and other masts. It is often incorrectly called a Conning Tower, which is a holdover from the older Fleet type submarines of WWI and WWII. The boat was controlled (conned) by the CO from an area above the main control room where the helm and planesmen and other crew were during an attack. The correct term for submarines with dive planes on the Fairwater is Fairwater Planes. For planes on the bow, they are called Bow Dive Planes, or simply Bow Planes.
Fairwater Planes have their problems though. In rough water, if the boat is at Periscope Depth, and is inadvertently sucked to the surface by a large enough wave, the boat can lose its depth control ability very quickly. If in a tactical situation, it makes it even more dicey if non-discovery is imperative. For this reason. the new Seawolf and Virginia class boats have gone back to Bow Planes, which give the boat depth control whether the sail is out of the water or not. A boat with a broached sail and bow planes can dive much faster than one with Fairwater planes can, since the latter must rely on bringing on more trim ballast to submerge when the primary control surfaces are out of the water.
There are 2 primary methods of surfacing a boat - an "Emergency Blow", used in emergency situations to surface rapidly, and a "Low Pressure Blow".
During an EB, compressed air stored in tanks (outside the pressure hull in the MBT's) is released rapidly into the Main Ballast Tanks to expel water and thus create Positive Buoyancy. The other method is a Low Pressure Blow, using the boat's onboard Low Pressure Blower (essentially a large fan blower) to slowly blow air into the MBT's. This is only used near the surface at Periscope Depth, as it requires the Snorkel Mast to be raised. Utilizing the LPB saves vital compressed air, which is used for emergency systems and weapon ejection. A Low Pressure Blow is the most common method of surfacing a Submarine in a non-emergency situation. The backup Diesel Generator exhaust can also be used in place of the LPB if needed, though the ship's ventilation system must be rigged to pipe the exhaust to the ballast tanks.
If you've seen pictures or film of a boat's bow coming out of the water at a steep angle at high speed, that's the result of an emergency blow at deep depth. It takes about 90 seconds from Test Depth to broach the surface, with the engines pushing the boat at full or flank speed. It's a hell of ride, and one that we all looked forward to as we didn't get to do it often, just for drills or certifications. Once the boat broaches, it sinks back down to about PD, and the LPB is used to fully surface the boat.
It is important to also note that the boat's propulsion type (Diesel-Electric or Nuclear) plays a big role in keeping the boat on course and depth. Without functional propulsion, any major casualty is next to impossible to deal with. It is this fact that is believed to be at the heart of the USS Thresher's loss.
In those days, during any casualty, the procedure was to perform a Reactor Scram (inserting all Control Rods to slow reaction to minimum), or to shut down the reactor. This left her without vital propulsion power after a major hull valve ruptured and left her with a major flooding casualty to fight. Pressure at deeper depths compresses air, and any air dumped into the MBT's during an emergency blow will take time to expand as the boat heads for shallower water. However, without functional propulsion, if the boat is sinking already, it's fighting a losing battle. Without the aid of her main engines to push her to the surface, Thresher's sinking was inevitable.
The loss of the Thresher led to many changes in the Nuclear Submarine program in the U.S. (SUBSAFE QA program), and for other Allied Nations with similar capability. Since the institution of the SUBSAFE program, there has not been a similar accident in the U.S. submarine fleet.
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What does cv in us navy stand for?
CV is the hull type designation for an aircraft carrier. This is not to be confused with the aircraft carriers of today, which are CVN. The 'N' stands for nuclear powered. CVs were conventionally powered with boilers.
Was a Japanese submarine ever sunk off the Oregon coast?
If there was, it was an unknown. However an IJN sub did launch an airplane which bombed Brookings Oregon. Sometime back in the early 90's, the pilot returned to Brookings as an "honored guest" (bygones being bygones), he apologized for dropping ordnance on their town (which they all knew he was just doing his duty anyway, war being war and all that...but he felt bad about it and apologized anyway); he gave the small town his samuri sword and they gave him the "key" to the their fine city.
Modern subs have recirculation pumps akin to air conditioning in say, big stores that go all the time, and have filters to keep pollutants, etc out of the seamen"s breathing spaces, a smart and safety-oriented idea. On atomic and modern Diesel subs these recirculation pumps- also akin to those on airliners, run all the time, at least when the vessel is submerged.
