Submarines

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.

The Soviet (later Russian) submarine "Losharik" (Project 210) design (multiple pressure-hull spheres with a submarine external superstructure) is believed to be able to approach depths approaching 20,000'. As far as being silent, reactors can only be quieted so much, and the sound profile characteristics at that depth mean that any sound she generates would be pushed back toward the surface by sea pressure (cold temperatures bend sound down in the ocean, until pressure forces it back up) with a vengeance. While she'd have an advantage in deep, cold water, she'd be vulnerable to detection within the 100 fathom curve of most continents (where the edge drops from shallow to deep depths) like any other boat.

While such a design might make it able to dive deeper and quieter, it also exacts strict limitations in equipment (weapons, sonar, etc.). While a unique design, it's more of a long-range independent DSRV / Research platform than a traditional submarine by naval warfare concepts.

The vessel was originally laid down in 1988, but over the years the lack of funding after the collapse of the Soviet Union led the Russians to actually seek outside investors to complete it (including Americans, who declined). This is likely due to Soviet-era submarine reactor technology, which had significant problems. Either way, the boat's design makes it essentially useful only as a rescue/special operations/research platform, not unlike the U.S. Navy's NR-1 and DSRV, though on a much larger scale and with its own power source, not requiring a tender to launch and recover.

It's most likely that the Soviets, having gained considerable intelligence knowledge from spy John Walker in the 80's, and release of the story concerning Project Azorian in the early 70's (erroneously called Project Jennifer by the press), could also have envisioned their own spy boat in the spirit of the U.S. Navy's USS Halibut (SSN-587) (Soviet submarine K-129 discovery/imaging), and USS Parche(SSN-683) ("Operation Ivy Bells"), but with much deeper depth capability, which was a limiting factor in the recovery effort of the K-129 by the CIA. Both the Halibut and Parche were used extensively in research, special operations, and rescue roles. Since the decommissioning of those boats, the Seawolf-class USS Jimmy Carter (SSN-23) has replaced them in those same spy roles.

With the intelligence-gathering aspect it's important to also note submarine concept design and implementation; it takes many years for the concept to go into actual production (even for the Soviets, who experimented with many design concepts). This means that the idea for Project 210 likely started in the late 70's or early 80's. As an example, we were first briefed on the initial Seawolf-class design in 1982, but 7 years before the first hull was laid down, and another 9 before commissioning.

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.

Kapitänleutnant Werner Hartenstein was the commander of the Kriegsmarine U-boat U-156, which sank the RMS Laconia by torpedo off the coast of West Africa on September 12, 1942. The affair, known as the "Laconia Incident", also saw other U-boats in the area join Hartenstein's crew in helping to rescue survivors.

However, heading to Vichy France, and under Red Cross flags, the U-boats came under B-24 Liberator bomber attack. The incident had far reaching consequences, forcing Germany to cease attempts at survivor rescue or assistance. There were commanders, however, who defied the orders.

Turtle was the world's first submarine used in battle. It was invented in Connecticut in 1775 by American Patriot David Bushnell as a means of attaching explosive charges to ships in a harbor.[1] Governor Trumbull recommended the inventor to George Washington and although the commander in chief had doubts he provided funds and support for developing and testing the machine.

The submarine was designed as a naval weapon, and it was meant to drill into a ship's hull and plant a keg containing 130 pounds of gunpowder, which would be detonated by a time fuse. Much testing was done by the inventor's brother, Ezra Bushnell, in the waters of the Connecticut River.

Named for its shape, Turtle resembled a large clam as much as a turtle; it was about 8 feet long (according to original specs), 6 feet (1.8 m) tall, and about 3 feet (0.9 m) wide, consisting of two wooden shells covered with tar and reinforced with steel bands. It submerged by allowing water into a bilge tank at the bottom of the vessel and ascended by pushing water out through a hand pump, similarly to the use of spear sack tanks in modern submarines, and was propelled vertically and horizontally by hand-cranked propellers, the first recorded use of the screw propeller for ships. It also had two hundred pounds of lead which could be released in a moment to increase buoyancy. It was manned and operated by one person. It contained enough air for about thirty minutes and had a speed in calm water of about three miles per hour.

Six small pieces of thick glass in the top were the only source of natural light. After Bushnell pondered the problem of lighting the inside of the ship and after learning that using a candle would hasten the use of the limited oxygen supply of the air inside, he solicited the help of Benjamin Franklin who cleverly hit upon the idea of using bioluminescent foxfire to provide illumination for the compass and depth meter. The light given by the material was said to be sufficient at night, though likely dimmer than expected, because the ship was cooled by the surrounding sea water and the metabolic rate of poikilothermic, heterotrophic organisms is temperature-dependent.