Submarines

This question isn't so good, and I'll explain in a second.

First, the answer your teacher wants is "more than 165psi." At 100 meters, the water pressure is 11 atmospheres, or 165psi. If you want to blow the water out of the ballast tanks, you need to apply enough air pressure to force the water out of the boat--or more than 165psi.


There are a couple of reasons why the question is bad.


When a submarine is submerged, they put enough water in the ballast tank to give the submarine neutral buoyancy. If the boat is large enough to displace 10,000 gallons of water and it weighs 60,000 pounds, it will float because 10,000 gallons of water weighs 80,000 pounds. If you add 20,000 pounds of water to it, the boat will weigh 80,000 pounds and it will neither float nor sink--and once it weighs this much, they make it rise or fall in the water with control surfaces like an airplane has. So you don't really have to blow the tanks to get the boat up from 100 meters.


Second, blowing the water out with air is only done in a real emergency. It's noisy, and doing anything noisy in a submarine gets you killed. They even have special shoes with soft soles so the enemy can't hear sailors walking around, and the beaters on the mixer in the galley are vinyl covered so you can't hear them scraping the sides of the bowl. They use pumps to remove the ballast when they need the sub to float.

Good point. That makes it do-able. In neutral buoyancy it would have to be more than 9.9*10^5N/m^2, in order to push the air out of the ballast tanks.

In Submarine Warfare, "areas" are defined as patrol areas; e.g., for a Fast-Attack submarine, her patrol area may cover a specific ocean or coastal area, or ahead of a Carrier Battle Group/Task Force if providing escort/screening duty. For an FBM (missile boat), their area will put them in the optimum launch position for their targets should they ever get an order.

The answer is ASDIC

At sea and underway, the measurement is in Feet, and it is measured from the Keel of the boat. If it's past a "certain point" it's not a good thing.

While in port, the Topside Watch notes the ship's draft depth in feet by noting the depth marks on the rudder every hour. This is done to detect any flooding that might not be readily apparent.

There are depth gage repeaters in Sonar Control, Main Control on the Helmsman/Planesman panel, and one in Maneuvering where the Reactor, Engines and Turbine Generators are operated. This is a safety feature in case the primary in Control goes bad or gets stuck for whatever reason. Someone is always monitoring depth. It has happened in the past where a main depth gage has failed and a boat drifted too deep, but was saved before it hit crush depth when the guys in Maneuvering saw they were below safe depth limits. Any time a submarine goes to deep depth, it is rigged for Deep Submergence - all damage control teams are in place and watches are essentially at battlestations.

The air found in the submarine makes it float

The same way anyone else does; the only difference is the design of the toilets, and the proper nautical term is the "Head", not the bathroom or toilet.

Unlike standard toilets made of porcelain, submarine toilets are made of CRES (Corrosion Resistant Steel), and don't use a gravity flush system like home toilets, or pressure-flush like commercial toilets.

On a submarine toilet bowl, it's a pretty simple setup. There are 2 valves, one for seawater to fill the bowl, and a 3-4" ball valve that's connected directly to a 3' long handle that is manually operated.

After a user has deposited whatever contents into the toilet bowl, the seawater valve is opened by hand to let water into the bowl, and then the ball valve is opened, letting the content of the bowl drain into one of the main Sanitary tanks. In port, the tank is pressurized with hi-pressure air, and forced to the pierside sewer connection; at sea, it is just blown overboard to feed the fish.

There are a couple of "hazards" with this type of setup however.

Before the Sanitary tank is emptied in port or at sea, the sailor on watch responsible will ensure that all the stall doors have warning signs on them that tank is being pressurized, and for crewmembers to NOT OPERATE the ball valve unless they want a face full of hi-pressure nastiness.

While most of the time things go as planned without any incident, there are occasions when the watchstander who is doing the tank blow operation forgets to put up the signs and someone gets nailed, or the signs ARE put up, and a crewmember just "has to go", but goes with the notion of emptying the bowl after the blow operation is completed. The problem with that is that when you're extremely tired, after doing your business, pulling that valve handle is as automatic as pushing a regular toilet lever at home, so accidents do happen occasionally. There's nothing quite like seeing someone who's been hit in the face with seawater and crap blown out of a toilet bowl at 1000 psi.

On rare occasions, the Sanitary Tank main outlet valve will get clogged; the only way to unclog it is for someone to physically enter the tank and do it manually. I won't go into the particulars, but suffice it to say that straws are drawn, and full face masks/protective gear is worn before diving into the tank. It's the same as entering a full septic tank on land.

The weapon described is a depth charge.

They were built pretty much like any other boat of similar size, on a slip bed, on a wharf. Main difference being the specialized inside, and that they had to be water tight on top as well.

just for curiosity

Follow the link below to the "Friends of the Hunley" site, where there are excellent pictures of the Hunley's recovery and close up pictures of her in the preservation tank. Friends of the Hunley is a non-profit organization created by South Carolina's Hunley Commission (established by the SC Government), for fundraising efforts aimed toward the Hunley raising and preservation effort.

No there were no tanks planes OR submarines in ww1. My friend Dennis ate them all.

Nuclear Energy

Only if they sink beyond their stress limit (crush depth). Subs are built to withstand the pressures very deep and will not "implode" unless they sink in very deep water. Don't forget; It is very rare for a submarine to sink with its pressure hull intact. Why would it sink when it is not taking on water? When it is taking on water and sinking, the water will enter the submarine at enormous pressures so the submarine will be flooded before it implodes. If, during the sinking, a compartment was sealed off from the compartment that is flooding it could implode but normally something else will give way (a hatch or a pipe) and so that compartment will also be flooded.

An American, David Busnell built the first successful military sub; piloted by Sgt. Lee of the Continental Army, the "Turtle" attacked a British warship (unsuccessfully) in 1776.

To cut Britain, Europe and Russia off from deliveries of badly needed supplies.

A U-boat

I assume you mean World War I, when the U-boats were the scourge of the seas. Yes the Allied nations had subs, in part to counter the threat of German submarine actions. A popular tactical idea of the time , espoused by the (battleship admirals) was the idea of Fleet Submarines with a high surface speed which could operate with the fleet, say with a major task force of surface ships-rather than an independent subamrine arm operating alone, as most did, or in organized (Wolf Packs) which would attack convoys of transports, etc. The pro suface fleet men espoused the Fleet Submarine concept- The RN had several (British_) some as hot on the surface as a destroyer (they were steam-electric with special retractile stacks) and odedly Czarist Russia had the elite A-9 class. the a-9"s were medium sized subs with good sea-keeping characteristics-in line with the fleet sub role- They had steam-e;lectric drive(naptha or alcohol burning boilers for the steam turbines) and a high surface speed, according to sub expert Norman Polmar War I A-9 class could do 26 Knots on the surface, a good rate of speed for a surface craft!. up to 23 knots at (Siphon depth) on the main engines- the Russians used the siphons to keep them running up to , well siphon depth, and recharge the batteries, on pure battery power they could go deep, at least l50 metres or so, but- could only manage 5 knots -Running on the batteries was thus, a tactic to avoid. so went the Russian fleet subs of War i- A-9 might have been codenamed- and the use is appropriate(can be used in command form to mean (Resurface!)- The Anastasia! Czarist sub, right comrades? Anastasia has nine letters and begins and ends with a. a good code cipher, and- appropriate in meaning- May she rise again! we wuld wan t s sub called(Bottom feeder or Catfish?)

The density of a Submarine never changes - what does change is its buoyant properties. The boat must maintain what is known as Neutral Buoyancy throughout different changes in water as it travels through the ocean. Temperature and Salinity changes are the 2 biggest factors in maintaining NB.

There are 3 primary methods for maintaining submerged operations:

1. Main Ballast Tanks

2. Trim Tanks

3. Dive Planes

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), and the bottom of the tank has an open grate, where the top of the tank has a hydraulically activated valve. 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 can be opened 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 purge water from several Trim Tanks on the boat. Trimming the boat gets the boat to Neutral Buoyancy, which is a submerged state in which the boat neither rises nor sinks. This is also used by Scuba Divers, and how they maintain their own depth control. 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.

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 that houses the periscopes and other masts. It is often incorrectly called a Conning Tower. As such they are referred to as Fairwater 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 or not the sail is out of the water or not.

There are 2 primary methods of surfacing a boat - an 'Emergency Blow" in which compressed air stored in tanks is released rapidly into the Main Ballast Tanks to expel water and thus create Positive Buoyancy; and a Low Pressure Blow, using the boats' onboard Low Pressure Blower. 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.

With the concentrated use of anti-submarine ships and aircraft.

Whenever they became a target of opportunity.

Fluid dynamics are essential for most major systems onboard a modern submarine. Hi-pressure hydraulics are the primary method of activating key valves in major systems, though they all have manual backups as well should the hydraulics fail or be damaged.

For power, most western nations used Pressurized Water Reactor designs, which is the most successful to date. For the US Navy alone, over 500 Reactor years of safe operation have been completed. There is no tolerance for even the slightest mistake in the Nuclear Navy.

For Oxygen generation, Electrolysis is used by a machine known as an O2 generator (or more commonly called "the bomb"). O2 is generated from water made by a water evaporator and then distilled further for use to make O2. The O2 is pumped into storage tanks, and released into the boat as required to maintain required levels.

For weapons launch, water impulse is used to eject the weapon from the tube.

As I said also, all valves onboard a boat are also manually operable, but they are also operated by hand operated hydraulics.

Modern submarines depend on fluid science - without it, they could not function.

The hull of the submarine will crush or give way if the pressure of the water is too much.