How can a submarine run on silent. Surely there will be engine nosies?

Answer 1

Worm drive. See the movie 'Red October'.

Answer 2

The old diesel boats generated electricity on surface and charged batteries to be able to run submerged Run silent riun deep.
However silent is not totally silent unless the sub was only moving at about 1 knot to maintain some balast and depth to avoid detection.
All subs had their signature tones in the propellors which often indicated the class of the sub its speed and direction. This is what the sonar operators were trained to hear and identify.

With the nuclear subs of course they can stay submerged without surfacing and only need to snorkel at night to replenish air, although scrubbers can do that and maintain air purity for up to 2 months. Despite the power base, the screw or props still give away it's presence to a trained sonar operator.
The Collins class sub built in Australia is the noisiest sub ever built and its noise is not all from the propellor, the damn thing is anything but streamlined and sets up a humm that can be heard miles away by sonar. There are other sound too but the whole thing is supposedly classified so i cannot reveal them to you here.

Answer 3

A modern sub is a technical marvel. All subs when submerged (either nuclear or diesel) use electric power(diesel) or steam(nuke) for propulsion. So there are no engine noises. Billions of dollars have been invested in propeller research to create a design that produces little if any cavitation. Especially at low speeds. And the inside of the sub has soundproofing and rubber coated decks for noise abatement.

Answer 4

not sure about a nuke, i think its steam until silent run. then its stored electric. no solid bangs so the light sound waves made by the rotating mech. are harder to detect. i did stand outside the welding room for the reactors with a glow in da dark badge lmao. trident class subs are humongous.look up subs doing emergency surface. cool as anything.

also as a man who participated in a medical offload from a nuc sub in the mouth of pearl harbour,like off the point of hickam, i can say as the sub periscope surfaced, it was like 3to4 ft out of the water before i spotted it. silent except for a lil splash that caught my attention.

Answer 5

Present day submarines use nuclear power, which doesn't make any noise. the old diesel boats only ran on engines on the surface

Answer 6

Present day submarines use nuclear power, which doesn't make any noise. the old diesel boats only ran on engines on the surface, when submerged they ran on batteries.

Answer 7

the electric power is incorrect. the nuclear boats are steam powered. they have a diesel generator for emergencies only. to run silent is to reduce speed and all functions of the boat to bare minimum to maintain steerage. when submerged, a boat must maintain forward motion or it sinks, much like an airplane. air & water are fluids.