Submarines

ww2 submarines usually tried to hunt down and destroy enemy subs, sink high value ships like aircraft carriers or attack trading/commercial ships.

ADDED: The Allied navies' submarines were generally used against enemy warships. The main target of the Nazi U-boats was the merchant-shipping convoys on the Atlantic, though others certainly did roam further to attack naval vessels. One U-boat even managed to sink a ship within the St. Lawrence Seaway, but they normally patrolled much further out.

Though Diesel-Electric boats are in fact much quieter on the battery than Nuclear Powered boats (the first thing taught in Sonar school), even with today's battery technology, DE submarines are limited in range, equipment, speed, maneuverability, and weapons they can carry. This in effect limits their overall usage as a weapons/intelligence/covert insertion/Naval escort platform.

In the early '60's, there was a big debate over the cost of nuclear powered boats vs. conventional DE submarines, as the success of the USS Nautilus (SSN-571) led the Navy to push for more of its type. A tactical test pitted one NP boat against several DE submarines - in simulated attacks, all DE boats were discovered and sunk by the NP submarine. This is what led to the Navy's current doctrine of using only nuclear powered boats.

One of the largest drawbacks to DE technology today is the major advancements in Anti-Submarine Warfare (ASW) technology, which has developed considerably over the years since WWII. Though the biggest threat to any submarine is still a submarine, patrol aircraft (fixed-wing and rotor) use sophisticated sonobuoys and dipping sonars that can direct surface and other air assets to the area to track and destroy a submarine. In such cases, the ability to go deep and rapidly egress the area is paramount, and the speeds/depths of modern NP submarines allows them to do that, where DE submarine technology is limited in that regard.

A submarine is a sea going vessel that is designed to run submerged or on the surface of the sea. Basically, by filling ballast tanks with sea water, the submarine will sink, and by blowing out the sea water from the ballast tanks with compressed air, the submarine will float on the surface.

Submarines can operate under water, but not under land. The US is a nation on land, and submarines cannot operate under it.

In January 1960, Jacques Piccard and Lt. Don Walsh of the US Navy made the descent in the submarine Trieste to the floor of the Mariana trough

20,000 Leagues Under the Sea; Captain Nemo's Nautilus.

Underseaboats.

No - there has never been a submarine with that name in the current or past Naval fleet. The only ship to bear the name Poseidon was USS Poseidon, (ARL-12), an Achelous-class repair ship in WWI.

There was a movie, USS Poseidon: Phantom Below, which had a fictitious Navy submarine called the Poseidon. However, the hull number is for the active commissioned submarine USS Georgia (SSGN 729), and there has never been an attack submarine with that hull number or designation.

Hollywood rarely uses real hull numbers of active ships to avoid any legal problems. The exceptions are those in which the production involves ships/submarines in which the storyline actually involves them. For example, The Hunt for Red October featured the USS Dallas, a real LA-class fast-attack submarine, of which an old friend of mine served aboard during filming. Usually though, the film will use a decommissioned hull number - many older films use 593, the hull number of the Thresher, which sank in the early 60's.

Contrary to popular belief, submarines don't use their main sonar systems for primary navigation (they don't have windows either), and the Sonar acronym meaning (Sound Navigation and Ranging) is actually a misnomer. However, they do use it for avoiding objects (ships and submarines), so in that sense they do use it for avoidance navigation.

Submarines use 2 types of Sonar modes - Active and Passive. Active Sonar is equivalent to Radar, only it uses sound waves rather than radio waves as the source of the transmission and echo for target range. Passive Sonar, which is used almost 99% of the time, involves simply listening with all systems for signs of ships, aircraft, or submarines (yes, we can hear planes and helos if they're close enough to the water).

Sound travels much faster in water than it does air, and travels much further as well. Active/Passive systems use a transducer array, which is a large array of devices (transducers) that convert electrical signals to sound (for active transmitting) and sound waves to electrical signals (for passive reception of sound or receiving a return echo). Passive-only arrays (towed arrays and secondary forward arrays) use hydrophones rather than transducers, which can only receive sound waves and convert them to electrical signals.

All submarines use chart, satellite, gyro, visual, radar (close to shore), and dead reckoning for primary navigation in most oceans. On rare occasions, uncharted mountains or navigational screwups have led to submarine accidents. My own boat hit an underwater mountain in the Mediterranean in 1977; the USS San Francisco hit an uncharted mountain a few years ago.

The one exception is in the Arctic Ocean, where the ice pack is in constant motion and its configuration is ever-changing. In the Arctic, for fast travel, the boat will submerge to a deeper depth than ice keels can form; for navigating through the ice pack near the surface, forward-looking and top-sounding hi-frequency sonar is used to both detect ice and determine its relative thickness. The periscope can also be raised (the water is extremely clear there) to get a visual confirmation of ice configuration prior to surfacing.

Navigating in the Arctic isn't easy. The aggravating, constant noise from the ice shifting (think about having to listen to popcorn pop for hours while trying to find a target) makes it very difficult to pick out contacts. Fortunately, there aren't any noisy biologics (fish, etc.) or shipping noise to make it worse.

The primary use for a submarine's main Sonar system is to find surface and submerged contacts. Depending on the type of boat (Attack or Missile) and its mission, a boat will either seek out those contacts or seek to avoid them altogether. It is the mission of a Fast-Attack submarine to seek and destroy ships and submarines; a Ballistic Missile submarine's mission is to remain undetected. For those like me who were Sonarmen during the height of the Cold War, being on a Fast-Attack was the only way to go if you wanted to learn your profession.

Not that submarines can't use their main sonar systems to navigate if they wanted to - they could. It can be used for navigation in shallow, close-to-shore waters, but in the deep ocean you can't due to the physical configuration of the Sonar array (more on that below). To use sonar for navigation, a boat needs to use Active Sonar. All boats use Passive Sonar exclusively for normal operations - active is only used to get a range confirmation on a target just prior to torpedo launch, or in other rare circumstances. The reason for this is that a boat's active sonar is extremely powerful, and as such can be heard by other ships and submarines for many, many miles (sound travels faster and farther in water than it does in air). Using active sonar effectively gives away your position, and in submarine warfare, he who hears the other one first, wins.

Sonar depends on a clear echo return from an active pulse for navigation. As such, the echo is dependent on the return angle of the sound back to its source. The problem in deep ocean is that the bottom is far enough away from the Sonar array that the angle at which the sound hits means that the echo will travel away from the source, not necessarily back toward it. This is why fathometer transducers are located on the bottom of the hull and slightly angled toward the bow to compensate for traveling through the water.

Even using Active Sonar for navigation close to shore isn't that easy, nor is it really that accurate. The power output is so great that the resulting echoes make for a pretty messy return image. Sure, you can adjust the power levels, but the reality of today's submarine operations is that the only time you could really use it is when transiting to and from port, and in those cases you'd be using satellite, chart, and visual aids, which are more accurate. Fathometer soundings are used regularly to correlate with chart information, and satellite fixes are checked with other systems.

In the case of using Passive Sonar, how sound travels in water is affected by temperature, salinity, and atmospheric pressure. Sound travels toward colder water, so as such tends to travel toward deep water. However, at deeper depth, pressure becomes the overriding variable and sound is forced back toward the surface. It is Sonar's job to chart the sound profile of the operating area on a regular basis so that the Sonar system can be used to full efficiency. Listening to Passive Sonar is essentially trying to pick out distinct sounds among the thousands of sounds created by biologics and environmental sources (storms, geologic sources, waves, etc.) as well as the thousands of ships and other man-made sources on the ocean or on the shore, trying to determine if the Sonar contact fits into the class of a Merchant ship, Trawler, Warship, or other type (Sailboat, Cruise ship, etc.).

Women have always been allowed on submarines - they just haven't been allowed to serve as crewmembers aboard them until recently, and even then, it's female officers only. Even the order to integrate them into crews may ultimately backfire - submarine duty is all-volunteer, and the current administration hasn't considered that the submarine force might un-volunteer itself if forced to accept something that would create a lot of hate and discontent.

Typically, women riders can be aboard for days or even weeks, but in those rare cases, they usually are berthed in the XO's or CO stateroom, which has its own lock and shower facility. In the cases where they might be assigned to the Wardroom, there are strict procedures in place for them to follow to ensure their privacy.

The primary reason for no female crew has been the complete lack of privacy - submarines are an extremely close-quarters environment with no privacy whatsoever, and have always been designed as a single-gender vessel. Larger Trident subs could likely accommodate the change, but attack submarines would have a difficult time at best.

The integration of women on ships has had a lot of problems that the Navy doesn't publicize (higher pregnancy rates, prostitution, to name a couple), and the health hazards unique to submarine duty haven't been brought to light due to security levels. It's one thing to want something when you don't know the full extent of the hazards. Radiation isn't a big concern for most of us who've served for years on boats, but all of the other chemical hazards are. There's a good reason submarine duty is considered hazardous, and it's not due to its mission requirement. I don't know of anyone (myself included) who's ever served on submarines who got away with a clean bill of health. Of large concern (and the reason the British Royal Navy bans women from serving on submarines) is the effect a submarine atmosphere would have on a woman's child-bearing capability. Possible medical complications of submarine duty isn't in the recruiting literature, and they sure don't tell you that when you volunteer.

Another concern for years has been the objection of crew wives and girlfriends to the possibility of women with their men in close quarters for long periods. Submarine crew divorce rates are already around 70%, and the additional tension from such a situation means that overall crew effectiveness would drop. It doesn't make any difference whether or not anything was going on, it's the possibility and suspicion. Fraternization on surface ships causing multiple problems, and in some cases CO's being relieved of command, has been an ongoing problem since combat vessel integration happened years ago. Sailors have a hard enough time convincing wives and girlfriends they're not cheating on them when they hit ports, much less if women were serving in tight spaces. There is already a lot of pressure for sailors to leave the Navy because of long family separations or other family issues, and this would add to it. I myself left after 8 years because I got tired of coming home and my daughter didn't know who I was, which is very common for most sailors.

The only real solution is to have an all-female crew, but I don't see that happening soon. As I said, unlike surface combatants and pilots, submarine duty is all-volunteer, and forced changes within the force aren't accepted easily. Integrating women on ships wasn't that hard, but submarines are a different story.

Take some toast weigh it down and stab something through it that floats. Itwill get soggy underwater and release the floating object

Only in special circumstances, and that's typically if you're medically discharged after being wounded, or your duty has caused health issues that leave you unable to continue active service. For all others, 20 years minimum.

Of course there are waivers for any situation, but medical discharges are the most common, and you don't often get full benefits. It depends on the situation of the individual, and for most it's like SSDI.

Submarine construction is much like a thermos bottle. What you see on the outside is the outer hull, or superstructure. The inner pressure hull is more spherical in shape and can withstand higher pressures.

All hatches, be it entry hatches, trash tube, torpedo tube, missile tubes, etc., have primary and secondary access. All hatches also have an inner O-ring seal to further maintain watertight integrity. A major safety feature is that no 2 hatches / doors can be open at the same time.

For certain valves, called "Hull Valves" (those exposed to direct sea pressure) they are constructed and maintained under a program called "Subsafe", at least here in the U.S. This program was a direct result of the loss of the USS Thresher (SSN-593), which had a major hull valve rupture and sank during sea trials. Since the implementation of the Subsafe program, there hasn't been an accident like it in the U.S. inventory.

Essentially, hull valves go through a very strict welding and inpection process to ensure that any possible failure is minimized to the fullest extent.

All valves and hatches exposed to direct sea pressure are also monitored for any water leakage on a regular basis, as are the bilge levels. Any increase can mean a seawater breach. A small breach at extreme depth can be catastrophic, as the sea pressure on the hull is enourmous.

Filling the ballast tanks with water increases the submarine's density. This will cause it to sink into the water. Blowing out the water with air reduces it and the sub will return to the surface.

Modern DE submarines do have limited O2 generation capability, though the main reason it's limited is due to the enormous power consumption that electrolosis requires. Even on the surface with their diesel engines running, the electrical output just isn't enough for sustained O2 generation of any magnitude, and submerged battery operations negate using it. Nuclear Powered submarines generate more than enough power to produce enough oxygen to stay submerged indefinitely.

The length of a manned submarine varies from a few tens of feet (in the case of little research subs) to several hundred feet for the big military u-boats. The Soviet Typhoon class boats, the largest submarines, are 175 meters long. That's close to two football fields in length.

military submarines use low frequency antenna that extends from the sail(conning tower.)

The message is typed into a computer, then is sent to another submarines antenna that receives it and displays it on a computer.

Echolot a German device used timed (Pings) developed in Interwar period. also applied to Blimps ( another Naval application!) as the Sonicaltimeter- note the blend word like modern computer-age run-ons. The Sonic Altimeter was used to determine ground clearance when crossing mountain ranges, for example, they were made by Echolot a German firm still in existence. Echolot was used on German Zeppelins in the altimeter mode.

Early in the war, the unrestricted use of submarine warfare against British Merchant shipping nearly doomed the nation. After supply ships began crossing from the United States, they became easy prey for the veteran U-Boat commanders. The primary use of a submarine, even today, is to ensure that you control the sea access lanes to your enemy, by attacking ships or submarines.

Eventually, the Allies countered the threat and ultimately doomed the U-Boats. Organized, Escorted Supply Convoys, escorted by Navy Destroyers and Frigates that could make the Transatlantic crossing to England, proved a real problem for the U-Boats. The use of Merchant Carriers, Merchant Ships that could carry & launch 4 Recon aircraft, also helped to nullify the advantage. The addition of RADAR on Navy ships meant a U-Boat at Periscope Depth or surfaced could be detected, even at night; and the ultimate employment of long-range bombers sealed the U-Boats fate. They never again enjoyed the success they had early in the war.

what does the term stabilizing fin mean

Pseudocysts are life-threatening when they become infected (abscess) and rupture. Simple rupture of a pseudocyst causes death 14% of the time. Rupture complicated by bleeding causes death 60% of the time.

Above ( perhaps Below a better adjective) Eyes Only) in the declassified tech manuals, the Depth gauge, while described is blacked out or the scale of feet is out of focus! hush hush.