How does a Diesel Submarine emit its exhaust smoke when under water ?

Answer 1

The old diesel submarines had a distinct disadvantage against the modern nuclear subs in that their primary power source could not function while submerged. Diesel requires oxygen as a component of combustion. While submerged the engines would use so much oxygen that the people inside the submarine would not have any oxygen to breath. The diesel subs had what we would call today a hybrid engine. While surface the diesel engines would operate to not only propel the sub but to also run electric generators to power up enormous batteries. When it submerged the diesel engines would shut off and electric motors would kick in to propel the sub. While the sub would still be limited in how long it could stay submerged based upon the power stored in the batteries it would still be longer that what it could stay submerged with diesel engines running on stored oxygen. You may have noticed that in old WWII submarine movies the lights would dim in the sub while submerged. This is to conserve the electricity in order to optimize the time under water. Also while surfaced the diesel engines would work to store oxygen in tanks for when they are submerged. In the end the diesel sub would not emit exhaust smoke because the engine would not be running. This is good as it would make it easy to spot an approaching sub by the greasy exhaust smoke it would be putting out.

Answer 2

The diesel engine on a diesel sub must take in air from the outside in order to run. Exceptions are those boats that have air independent operating diesels.

The sub can run on the surface, or if they want to reduce the likelihood of detection by others, they come up to periscope depth, and raise the snorkel to draw in air to the engine. At periscope depth, the exhaust normally exists via the sail (conning tower) and into the water below the surface. This can reduce some of the exhaust smoke. Running with the exhaust submerged usually lowers the capacity of the engine due to backpressure.

Ranb

Answer 3

A diesel sub is really a diesel/electric sub. When it is submerged beyond the depth of it's snorkel, it can only operate on batteries. When it is closer to the surface than snorkel depth, the intake is from the atmosphere. I'd assume that the exhaust is also through the snorkel, but it need not be, since the pressure isn't so great at that depth and the exhaust could be discharged into the water.

Answer 4

How does it get air when under water? The front side of the snorkel is the air intake. The rear is the exhaust vent. Some diesel subs had two masts.

Answer 5

They run on batteries powered by an electric motor. The batteries are charged when the diesel engine is running when the sub is at or near the surface.

Shaztashaman's answer is crap.

Answer 6

It runs on batteries under water, and diesel engines on the surface.

Answer 7

A Diesel Submarine can exhaust smoke while submerged. A submarine has a snorkel from which air comes in to run the diesel, the snorkel is raised above the water. The exhaust from the Diesel is exhausted from vents on the sail of the submarine.

Answer 8

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AC Delco makes a good product called "Top Engine Cleaner." It's like Sea Foam but much better. The hone is coked with oil and the rings are coked with oil. The other slight possibility could be pulling oil through a cracked intake, etc.

Answer 9

How Do Submarines Work

Answer 10

Yes. Per the gas laws of chemistry however, most of the time, cold water can absorb a whole lot of that gasseous exhaust, so you won't see any bubbles of smoke breaking the surface per se. The deeper a sub goes, the colder the water, the more water that gas can absorb, because its colder and under more pressure, both of which increase the ammount of gas that is miscible in H2O.

To boot, space ships, as well as some newer non-nuclear subs, use ionized litium now-a-days to free up oxygen to feed into the motor intake to be able to run a diesel turbin underwater. I think that only the Norweigans and Iranias use this tho, as my friend is a sub man in the navy and he's never heard of the US using this specific tech.