[MartinL]

[ How do crewmen on a sub know if they are submerged or surfaced?

They can see that they are on the surface via the periscope. There are depth gages that show the depth of the keel. When on the surface and not rigged to submerge the bridge hatch is open and there is a lookout on top of the sail. Prior to surfacing, the ship rigs the ship for surfacing. The lower pressure blower is also used to blow the ballast tanks dry after the sub drives to the surface and when it is operating it can be heard throughout the ship. There is also much more rolling around on the surface. With a portion of the round hull out of the water, the stern planes are not able to maintain much axial stability.

I also had another way to determining that we were on the surface even if I ignored everything else. Each sub has what is called a beta counter to count radioactive coolant samples. The background radiation level is determined each day and when something happens that changes the background radiation level in the lab. Due to the thick shield forward of the reactor compartment, the operations compartment of the sub received more radiation from the sun than from the reactor plant. So when on the surface, I could tell from the radiation level as determined by this sensitive instrument.

[rerevisionist]

MartinL - you said coming to the surface was routinely exploited. Now you switch stories to torpedo attacks, when they're underwater. You say also that you can't confirm the time spent underwater. But you quizzed a member here about his knowledge.

It's clear you will not produce any hard evidence. I doubt whether you have any, but from the point of this site it's immaterial. I'll wait in the hope someone with substantial evidence comes along.

[FirstClassSkeptic]

[ How do crewmen on a sub know if they are submerged or surfaced?

They can see that they are on the surface via the periscope. There are depth gages that show the depth of the keel. When on the surface and not rigged to submerge the bridge hatch is open and there is a lookout on top of the sail. Prior to surfacing, the ship rigs the ship for surfacing. The lower pressure blower is also used to blow the ballast tanks dry after the sub drives to the surface and when it is operating it can be heard throughout the ship. There is also much more rolling around on the surface. With a portion of the round hull out of the water, the stern planes are not able to maintain much axial stability.

I also had another way to determining that we were on the surface even if I ignored everything else. Each sub has what is called a beta counter to count radioactive coolant samples. The background radiation level is determined each day and when something happens that changes the background radiation level in the lab. Due to the thick shield forward of the reactor compartment, the operations compartment of the sub received more radiation from the sun than from the reactor plant. So when on the surface, I could tell from the radiation level as determined by this sensitive instrument.

Of all the crew on a sub, how many could use the periscope, and how many had access to all those meters? Aside from the rolling motion of the sub when on the surface, as opposed to being submerged, the only way to tell if the sub was submerged was to see various instruments. So how would the general crew member know if he was submerged, or just in calm surface water?

In all of those old WWII sub movies, they had a 'periscope depth'. They drew the periscope down when they dived. They would give the order, "Up periscope." and "Down periscope." So some crew member comes to the bridge, and says, "I want to look out of the periscope." and he's told, "We're submerged. The periscope is down." So the crew member walks away after being told the sub is submerged. But what has he been shown to prove it? You can't look out of the periscope to prove you are submerged.

Now, private subs have windows in them. But do military subs?

[rerevisionist]

BBC 27 June 2010 - How to Build, Series 1: part 1 - A Nuclear Submarine

https://www.bbc.co.uk/programmes/b00sz49v

This is being shown again and has 7 days left - up till about 6 March - so if you like archives, you might try a screen grab program. It's about just one single submarine, 'Astute'.

Terrible rubbish for my taste: silly music, inappropriate sentiments, absurd set-piece statements, and sad working class people being shown as naive, just as they're meant to be. However there are a few interesting points--

[1] No Trident. It has only torpedoes and cruise missiles. Presumably therefore its firepower is limited to conventional explosives in these missiles. Was this delivery system worth the cost? It seems unlikely.
[2] I don't think there was any information given about the torpedoes.
[3] They supposedly use passive sonar - i.e. no sonar, just listening; and elaborate anti-sonar rubber panelling. (I wonder if they were influenced by the accounts of whales' sounds being audible around whole oceans...).
[4] There's detail of diesel engines and batteries, and these are shown. There's also mention and computer detail of the alleged nuclear engines. Whether these actually exist is, of course, a sceptical point on this site: a speaker on the TV programme says when the reactor is at full power, it can power a city the size of Southampton. There's a slight problem here - the megawattage needed by Southampton can be guesstimated from its population, and the energy consumption claimed for the whole UK. Here's an error-prone Wiki site - https://en.wikipedia.org/wiki/Electricity_sector_in_the_United_Kingdom which gives about 6000 kWh per person a year - or about 700 watts an hour. Southampton has about 240,000 persons. This is 165 million watts per hour - sounds like far too much energy for the thing to dissipate.

Perhaps someone would like to comment more?

[voerioc]

Very good case rerevisionist.

So, we can wonder why nuclear submarines are not located with infrared radars. With such a heat to evacuate, it should be very easy to follow them with radars which react to heat.

[Exorcist]

re: BBC 27 June 2010 - How to Build, Series 1: part 1 - A Nuclear Submarine

I watched it last night. BBC 4...9 o'clock. It was unavailable for iplayer download then but is available now. Cost in excess of £1 billion/ sub. They've abandoned Trident which I strongly suspect is a non-launchable scam.

[FirstClassSkeptic]

Very good case rerevisionist.

So, we can wonder why nuclear submarines are not located with infrared radars. With such a heat to evacuate, it should be very easy to follow them with radars which react to heat.

Yes, that's what I was wondering about and asked about. It seems others have thought about this also.

If the reactor is 15% efficient, then you would have to multiply that 165 million watts by about six.

Now the technical explanation for why you can't track a sub by thermal signature is 1) infrared waves don't travel through the water very far, 2) the huge expanse of ocean water absorbs the heat. Therefore, a sub could only be detected by heat signature if it was near the surface.

But this is what I say: The sub would leave behind a thermal wake of heated water. That warm water would rise toward the surface. And what is considered 'near the surface'? The ocean is miles deep in many places, but subs only go to hundreds of feet. Did someone say 800 feet on here, for military subs? And I say that that's an exaggeration. It's probably more like 300 feet. But is 800 feet 'near the surface'? The point I'm trying to get at is; subs are always near the surface. Unless they sink.

There is 'satellite' technology that measures the temperature of the surface of ocean waters. It seems to me that such a nuclear sub, leaving behind heated water in it's wake, would leave an obvious snake like trail across the ocean, which these satellite sensors would pick up on.