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.
The dnsity of a submerged submarine is the same as the density of the water if the density of the submarine was grater it will sink, if the density was less it would float.
The density will rise and submerge the submarine.
The density will rise and submerge the submarine.
To rise again, the submarine's weight must be decreased. Air is pumped into the ballast tanks to force the water out. The buoyant force acting on the submarine now exceeds the submarine's weight. With positive buoyancy, the submarine rises. The less weight an object has the more its density decreases. Hope that kinda helps?
because of density
Increases
It is not the matter of density. When inflation tank is filled with water then the weight of submarine is more than the weight of the displaced water. So submarine is in the sinking condition. As water is pumped out then weight of displaced water which is known as Buoyant force would be more than the weight of the submarine. So it would float.
Density = mass / volume. If the mass decreases, the density decreases.
Density = mass / volume. If the mass decreases, the density decreases.
Density = mass / volume. If the mass decreases, the density decreases.
a submarine has a water tank. when the tank is filled then submarine sink in the water. and when the tank is empty then submarine float in water. use the formula density= mass / volume as mass increases(when the tank is full of water), the density of the submarine increases and it submerge into the water and vice versa.
the overall density goes up.