I watched a movie yesterday that took place on a submarine and noticed some things common in many sub movies I’ve seen. What’s fact and what’s fiction?
1). Something is always dripping, leaking. Really?
2). Leaks are patched or fixed in what appears to be just seconds. No welding. Really?
3). Crew is always silent when enemy is near because the enemy can hear them talking through all that thick steel and across the ocean. Really?
4). Food is stored all over the place, meat dangling from the ceiling. Really?
5). What is the red and the blue lighting used for?
I think I know the answer to at least the question about the red lights.
I believe they used red lights in the periscope room at night. That way you could look away from the periscope to consult a chart or speak with someone without compromising your night vision. Could be wrong on that tho.
If the leak is patched in seconds, without welding, I’d say it would be because it’s a patch (same for how you can patch a runway crater without pouring any concrete). The welding would be used for a more permanent repair when time allows, the patch is to keep the sub from sinking right now.
Not sure I’ve ever seen a sub movie where meat just hangs anywhere.
Red lighting is indeed better for when you need night vision. Stargazers use lots of red filters on their flashlights and such. Not so good if you need to be able to see certain red things easily, like any “red line” indicators on your instrument panel (under a red light, anything printed in red just looks like white).
That said, I know in some movies they’ll use different colored lighting to help tell different ships apart when they have a limited variety of sets, or for dramatic purposes. On Star Trek, all the lighting goes red in emergencies, while in the Hunt for Red October, red lights and white lights made it easier to tell the Russian subs from the American subs (IIRC, they only had one submarine bridge set for all three subs in the movie)
EDIT: Oh, and for being quiet, I understand that’s true. Submarines (and anti-sub helicopters and such) use some very sensitive audio equipment for detecting other ships. Water propogates sound a lot better than it does light or radar (and unless someone else is using radar underwater, you can’t use it to detect anything anyways without basically announcing yourself to anyone else who might have a radar set, whereas all mechanical things will make some noise, no matter how well masked.)
The dripping is just as likely to be condensation, especially in depictions of older subs with less efficient climate control systems. The air will be warm and damp, and there will be lots of cool metal surfaces within the submarine.
With regards to being quiet, the passive sonar systems are incredibly sensitive, crews would need to go to great lengths to avoid detection. Crews would be issued with soft-rubber soled shoes, and the handles of tools would be dipped in rubberised paint to minimise the chance of any rattles.
You don’t whip out the blowtorch while you’re being attacked, there’ll already be plenty of fire hazards in current conditions :). A quick patch-job is enough to stop or delay the flooding risk, and more permanent repairs take place when things are more quiet (i.e. off-screen)
Yes. Well, it’s not so much the talking (though modern sub acoustics *can *really be that good if the subs/helo sonar pod are close together, and during the Cold War that was sometimes the case) as what bubbleheads call “transients” - somebody drops a wrench, or a steam pipe gurgles, and suddenly they realize there’s a boat out there because nothing natural sounds that way. Even stomping about on a metal floor can be enough. So sub sailors do learn to be quiet at all times.
Not so true back in WW2, but I suspect getting depth charged or just going deep in a creaking rustbucket tends to get one nervous enough to shut up and pray.
In WW2 ? Absolutely true. Subs were small, cramped and patrols could go on for long stretches as their duration was not really fixed - you stayed at sea until you had expended all your torpedoes, fuel reserves ran low or you got too heavily damaged to go on, whichever happened first. In addition, in WW2 the Germans had a network of “milk cows”, submarines that would resupply other submarines at sea so they could stay active longer.
So yes, they did pack every nook and cranny with food knowing that the “problem” would solve itself along the way.
Preserve night vision. Back in WW2 this was important because subs ran on the surface most of the time, with rotating crews of watchmen using binoculars up top to spot ships.
In modern subs this is naturally less of an issue, but I *believe *they still do it to preserve a notion of the night/day cycle on the surface. Men tend to go a bit crazy when they start losing perception of that kind of thing. I’m sure a bubblehead will be right along to smack me upside the head on this
Mostly for dramatic effect, but when we patrolled in colder waters there was much condensation and icecicles would form.
Yup, depending on the size/location/type of the leak we’d use either a Band-it or Adams Clamp and have the leak patched in mere seconds. In the flooding trainer at Ballast Point (San Diego) it wasn’t unusual to see crews patch 50 or so fairly large leaks (water, water, everywhere) in <2 minutes using Adams Clamps and the water just barely reaching the knees. The Band-its took >10 and the trainer was completely flooded.
Absolutely. Modern SONAR is THAT good. Another reason for silence is that you can hear quite a bit of the outside world through the hull.
Meat was kept in the freezer. However, for a long mission (80-90 days) we packed the canned goods (Number 10 size cans) in the passageways and walked on the tops of the cans.
As already noted, for preserving night vision. During daylight hours topside we ran with white lights, switching to red lights at night. During the “rigged for red” hours the oncoming OOD would don red goggles at least 30 minutes before assuming the watch in order that his eyes would be night adapted. In the SONAR shack we used blue lights at all times, first, because it has been shown that subdued light actually enhances the sense of hearing, and second, some of our CRTs contained amber phosphers that pick up extra energy from, and begin to glow quite brightly under red light.
Most has been covered, but I’ll add a couple of things.
“Air noise” (i.e. voices, etc.) doesn’t really propagate outside of the hull, but direct hull-contact does (like dropping a wrench into the bilge). However, by encouraging the crew to be quiet at all times, you also encourage them to be more aware of not dropping tools, etc. On every submarine I served on, we even wore sneakers. (I wore New Balance running shoes.)
Most of the leaks are condensation, especially in the engine room. You have a large steam plant surrounded by cold metal, resulting in condensation. However, you also have seals, like the propeller shaft seals that are not 100%. Seawater does leak in.
Food is stored almost everywhere, but mostly in cans these days, and mostly in the forward compartment instead of the engineering and mechanical spaces. We did store some pallets of eggs in the Engineroom on deployments, though, back aft and low near the bilge where it was cool.
You mean sonar, Raguleader, which is sound-based. Radar does not work underwater.
While active sonar (the one with the pings) does give away a sub’s presence, modern submarines use passive sonar extensively. Indeed, it’s the main piece of detection equipment.
Modern radars use active electronically phased array which remain stealthy “by spreading their signal emissions out across a band of frequencies, which makes it very difficult to detect over background noise, allowing ships and aircraft to broadcast powerful radar signals while still remaining stealthy.”
No. Sonar is a single pulse (or rapid series of pulses) which actually reflects off of the dramatic change in density between the ocean and the air space inside the hull, rather than thr metallic hull itself. Passive ‘sonar’ doesn’t radiate anything; instead, it is a sophisticated series of acoustic sensors, audio filters, and processing software that looks for radiated acoustic sources that are unnaturally rythmic or intense (e.g. the operation of pumps, opening of valves or hatches, dropping tools, et cetera). As modern subs are covered with acoustically damping tiles, any modest external source will have essentially no reflection.
There are a few other means to potentially detect and track submarines (magnetic anomaly detection, thermal gradients) but passive acoustics is thr only practical means to do so by another sub that doesn’t want its own location to be revealed. For the most part, active sonar is only used by sonarbuoys (automated sound pulse generators dropped by ship or aircraft) and homing torpedeos.
Not really. Food going to the International Space Station is entirely containerized and packaged and there are no facilities for cooking food other than reheating and (very carefully) boiling. Pressurized space on the ISS is really at a premium, and of course it would not do to have containers or packages floating loose or strapped to random walls, so food is either stored in the larder in the Zvezda module or in Zarya with other excess gear and provisions.
I recall from books by WWII USA sub officers in the Pacific that fresh produce (sacks of potatoes, onions, etc.) was stored in the showers. Those were used up early in the voyage, because it wouldn’t keep long in the humid atmosphere onboard. When they were gone, sailors could now use the showers (but had more restrictions on their meals).
Some sonars do use Low Probability of Intercept (LPI) spread spectrum techniques like LPI radars. However, since the propagation characteristics of sound in water vary a lot more by frequency than those of electromagnetic waves in air, and due to the particular characteristics of background noise in water (into which you want the LPI sonar signal to blend), it’s more difficult and more limited, generally to shorter ranges. IOW LPI active sonars would not directly compete with long range passive sonars.
Some submarine active mine detecting sonars have LPI characteristics. An example is the Type 2077 sonar fitted to newer Royal Navy nuclear attack subs. Similar systems on USN subs are also believed to have LPI modes. Mines only need to be detected at pretty close range, can’t as a rule be detected by passive sonar, and you need to operate the mine detecting sonar without betraying the sub’s position.
Another potential application is on active homing torpedoes or anti-submarine Unmanned Underwater Vehicles where again active sonars would only need short to moderate ranges, and the torpedo or UUV could have a small enough signature to otherwise remain undetectable by the target sub at fairly short range. There is public reference to research into LPI sonars for those applications.
That is part of it. The other part is that light comes down the periscope from the surface, but light also goes back up the periscope from inside the sub. If the periscope room had bright white lights, that light would be visible on the surface coming out of the periscope.
