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US Navy
The US Navy is a service branch of the US Armed Forces that deals with naval warfare. It is the world’s largest naval force, and has the largest carrier fleet, operating 286 ships in active service and over 3,700 aircrafts.
3,634 Questions
The tiny particles in the air affect the colors of the sky at sunrise and sunset because they cause the suns rays to change directions. When this occurs it changes the suns rays and causes different color arrays.
Who was the first Secretary of Commerce?
William Cox Redfield was the first secretary of commerce for the united states commerce department which was started under the Woodrow Wilson administration.
In the Fighting Seabees what rate was John Wayne and what was his characters name?
He was Lieutenant Commander Wedge Donovan.
What does the as stand for in navy ship as-18?
The Navy ship hull designation "AS" denotes a Submarine Tender (Auxiliary, Submarine). The USS Orion (AS-18) was a Fulton-class tender from WWII, and in later years served many boats at the U.S. forward operating base in La Maddalena, Sardinia, until her decommissioning in 1993. Every boat crew who deployed to the Mediterranean (including myself) during her stationing in La Maddalena crossed the Orion's decks.
The Surface Navy equivalent is a Destroyer Tender (AD), which is essentially the same type of ship with different servicing capabilities.
What is the first Carrier Vessel Nuclear in us navy?
The first Nuclear-Powered Aircraft Carrier is the USS Enterprise (CVN-65). She has been in commission since 1961, the second longest commissioned Navy warship behind the USS Constitution. She is also the longest Naval vessel in the world.
She is scheduled for decommissioning in 2013.
Is a urethrocele a back or front wall prolapse?
Front wall prolapse. A rectocoele is a prolapse of the back wall
Bon homme Richard how do you pronounce it?
The sound of the first word "Bon" is the same sound as in bonfire or bond without the 'd'. The sound of the second word "Homme" is mostly silent and is the same sound as in mom without the first 'm'. The sound of the third word "Richard" is the French sound for Richard with emphasis on the soft second syllable like the sound in the name "Char"lotte or the color "char"treuse. When pronouncing the full name you would concatenate or run together the first two words with emphasis on the second word. This would result in the name sounding like "Bǒn´ǒm Ree´shär". I served on the attack carrier USS Bon Homme Richard (CVA-31) from 1966 -1969. And like her namesake captained by John Paul Jones, this grand lady served her country well and faithful.
There is no hard calculation, as the Speed of Sound in water, like air, is affected by the many variables which change constantly depending on the local ocean environment.
Key elements that affect the speed of sound in saltwater are:
1. Temperature
2. Sea Pressure
3. Salinity
Other factors that affect echo return:
1. Frequency of Active Sonar used (High or Low Frequency) & Type of Pulse (classified)
2. Target bearing rate and speed
3. Target Angle on the Bow (AoB)
4. Target Sonar Attenuation (stealth) Characteristics
3. Depth differential between Submarine and Target vessel (Ascension or Declination)
The 2 biggest factors affecting SoS in water are Temperature and Pressure. Salinity is only really a factor if you're in the Arctic waters, as the salinity is lower due to the increased freshwater melt from the ice pack. Temperature is the biggest factor, since sound, like electricity, follows the path of least resistance, which in the ocean is cold water. Temperature will drive the sound path toward colder water (deeper) until sea pressure overcomes temperature and forces the sound wave back toward the surface. For this reason, Submarine Sonar Techs always monitor the ship's Speed of Sound instruments (usually 2, which give continuous plots/readings), or in the case of an upcoming tactical operation, will launch an expendable Bathythermograph (SSXBT), which will give the sound profile from the ocean surface to around 2500' (or until the probe is crushed by pressure).
However, if you use an average of 5000fps for SoS in saltwater (we used to use 4950fps for daily measurments), you can figure the equation like this:
Total distance of Attacking Submarine Ping and returning Target Submarine Echo - 7000 meters (3500 x 2, distance to target and return)
7000 meters = 23,100 ft (4.375 miles)
23,100 feet / 5000 fps = 4.62 seconds
Again, it's a basic estimate assuming constant temperature and salinity between targets at the same depth, not moving. In reality, the tactical scenario gives you variables that change constantly as you're tracking the target submarine. Also, Active Sonar is virtually never used in modern submarine combat, unless it's to verify Range to Target prior to final bearing match during Firing Point Procedures, just prior to weapons launch.
To explain, modern submarine combat tactics use the submarines' maneuvering capability to generate bearing rate to plot target track and range estimate for a torpedo shooting solution, not Active Sonar. Unlike the old WWII John Wayne "point and shoot" torpedoes, modern torpedoes are wire-guided and have their own Active-Passive Sonar systems aboard that are tied to the weapon guidance system, meaning that they are shot toward the best estimate of range, depth, and bearing to the target. Once it gets there, it will begin a programmed Sonar search pattern; once it finds the target, it will home in using Active Sonar (there is nothing quite like the sound of an active torpedo homing on you at 55 knots).
If the target manages to evade the Sonar homing lock (unlikely if it locks onto the target vessel) Fire Control can re-steer the weapon to the target if the wire-guide is still attached and functional. Despite what Hollywood movies would have people believe, if a homing torpedo locks onto a target, it's pretty much history, regardless of countermeasures.
When did Michael R. Cannon join Solectron?
In 2003 Cannon replaced Koichi Nishimura as Solectron's president and CEO.
What pilot holds the record for the most aircraft carrier landings in one night?
LCDR J.C. "Uncle Dudley" Creasman in 1959-1960
What was Operation Slingshot in Vietnam?
I do not think it was called "Operation Slingshot"... It was called "Operation Giant Slingshot," which was a Brown Water Navy operation designed to interdict the North Vietnamese supply lines where the Ho Chi Minh trail entered South Vietnam in the 'Parrots Beak' area, where Cambodia juts into South Vietnam, west of Saigon. The operation established River Patrol and Rivron/Riverbed blocking forces on the Vam Co Dong and Vam Co Tay rivers, which bracket the Parrots Beak, and looks like a 'Giant Slingshot' on a map .The operation also involved army troops as ground forces within the riverine forces. I think it was the third Infantry, but I might be wrong on that point.
Why is the lookout post on the top of a ships mast called the crows nest?
The lookout post was atop the mast just as a birds nest might be at the top of a tall tree. From that vantage point the bird could see any potential threats that were approaching. The same is true with the lookout in the crows nest. They could see any other ships or reefs or anything that could cause a problem well before anyone on deck might see it.
How could my father be a petty officer in World War 2 when he was in the USAFFE ad a Captain?
Well, he was either one or the other.. couldn't have been both.
Was the Poseidon a U.S. Navy submarine?
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.
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How do submarines use SONAR to navigate?
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.).
What is the scope used in submarines?
There are several primary official and unofficial uses for a submarine periscope:
Official
1. Surface search and recon while at Periscope Depth
2. Getting a satellite fix (embedded receiver)
3. Taking a Star or Sextant fix (if needed)
4. Target tracking and Ranging
5. Classified Intelligence gathering
6. Visual navigational fixes close to shore
7. Surface visual navigation in heavy weather (when bridge access isn't viable)
Unofficial
1. Periscope Liberty (looking at the ocean after you've been submerged for a few weeks)
2. Long-range scoping of babes on the pier while in port (most important function of all), especially during liberty port calls.
There are 2 periscopes aboard modern boats, the primary and attack scope. The primary is used for most functions, while the attack scope serves as the primary visual range and bearing scope for attacks (visual confirmation of a target is required, even if a submerged sonar track on the target is being performed), as well as serving as a backup. The attack scope has a much lower profile and is much harder to spot (leaves much smaller wake).
In 1957, the Lawrence Livermore National Laboratory was selected to develop the nuclear warhead for the UGM-27 Polaris SLBM.
Big ships such as Navy's have periscopes and submarines have it too. If it is high for you to see you will use an periscopes.
