Real Submarine Technology & History Q&A - Page 34

DaveyJ576 · 10-30-10, 10:25 PM

Quote:

Originally Posted by Platapus

Now the Safety tank was a tank with the same displacement as the conning tower. Its primary use was to compensate for a flooded conning tower in case of an emergency.

As such the Safety Tank was normally kept full of water as it would be common practice to keep the conning tower empty of water.

The Safety Tank could be blown in case emergency buoyancy was needed.

"Put a bubble in Safety"

Is this strictly Hollywood BS?

Actually, no it is not BS. I think you are getting tripped up on jargon. "Put a bubble in Safety" actually means partially blowing the tank, emptying part of the tank in an effort to restore positive buoyancy, possibly as a result of battle damage related flooding in another part of the boat. As you noted, the safety tank is normally kept flooded at all times, and would only be emptied to compensate for flooding, usually of the conning tower, but it could be used in any flooding casualty. In this function, it has almost the exact opposite use as the negative tank, which is meant to provided negative buoyancy during the first part of the dive, to get the boat down faster. Once the boat is under, the negative tank is "blown to the mark". This is a predetermined point at which, when emptied to this mark, neutral or a slightly positive buoyancy will be reestablished. The "mark" changes constantly as fuel is used, garbage is thrown overboard, ammo is used up, etc.

Putting a "bubble" in safety would only be done if the boat was having difficulty maintaining neutral or positive buoyancy due to leaks or flooding.

Platapus · 10-31-10, 08:00 PM

Ah, so putting a bubble in safety is, in fact, adding a little bit more positive buoyancy to the boat?

Would a bubble in safety be put in times where there is no damage?

If the trim analysis for a specific dive were to be "Heavy overall and all right fore and aft", would a remedy be putting a bubble in safety to establish the trim?

(I love this thread, so much to learn, so many willing to teach)

Nuc · 11-01-10, 05:39 AM

Quote:

If the trim analysis for a specific dive were to be "Heavy overall and all right fore and aft", would a remedy be putting a bubble in safety to establish the trim?

No. Safety, as the name implies, was use only in emergency. Here you would probably pump from the trim tanks to sea.

kraznyi_oktjabr · 11-13-10, 02:18 PM

Platabus and Dave, thank you very much for your answers!

LukeFF · 11-16-10, 05:31 AM

Quote:

Originally Posted by DaveyJ576

I have spent the last week and a half revising the Wikipedia page on the Gato class submarines. The original was incomplete, misleading, and in some cases completely wrong. I think it will stand the test now. Take a look when you have the chance:

http://en.wikipedia.org/wiki/Gato_class_submarine

Enjoy!

Well done!

TorpX · 12-08-10, 08:48 PM

Hello everybody. I've been playing SH 4 for a little while, but am new to the forum. This is a great place and I always learn something here.

First, I would like to thank DaveyJ, and all the other Vets, not only for their service, but for the infornation and insights they provide.

Second, I have a few questions about the S-boats.

Patrol Endurance. How long could they remain at sea? Apart from fuel considerations how much food could they carry?
Battery Capacity. How far could they go while submerged? In 1941, were their batteries degraded or had they recieved refits before wartime deployment?
Surface Speed. How fast could they go in heavy seas? In SH4 they can plow through rough seas with little problem, but it seems to me this is a game flaw.

Thanks in advance.

Arael · 12-20-10, 03:53 PM

On the subject of the S-Boats, what is that funny little ball that's sticking up out of the deck near the bow?

Stormende · 12-22-10, 02:28 AM

Quote:

Originally Posted by kraznyi_oktjabr

I have question on following text from U.S.S. BAYA (SS-318) FOURTH WAR PATROL REPORT27 April 1945 at 0235:
"APR contact on 305 mcs., 200 TRF, strength 5. This contact was followed by jamming which effectively blacked both united of APR and completely blacked SD."

Could someone explain what are APR, mcs, TRF and this "strength 5"? Also what kind of jamming gear Japanese would be using?

EDIT: Okay I missed section where APR was mentioned to be somekind of radio, my bad. Would still like to hear more about it.

Thanks!
Tim

305 Mega Cycles (now MHz) APR/SPR (Shipboard Radar Receiver), meaning the radar picked up a contact on 305 Mega Cycles, then the RBS detected an emission on 200 Kilo Cycles (kcs), I believe this was the so called jamming signal which had a strenght of 5 (bars) as it was already explained by Platapus.

... RCM receivers were very effective in detecting enemy radars at ranges far beyond the range of our own radars. This is because we could detect their strong transmitter pulses at ranges where echoes were too faint to be received. Good RCM operators could tell when snoopers were searching, when they had discovered us, and when they were commencing a run on us. RCM transmitters of fairly low power (10-100 watts) could thoroughly jam the enemy’s radar receiver, since echoes bounced off of us would have only milliwatts of power. (sic)

Check these sites for more detailed info:

http://www.ka8vit.com/subops/default.htm

http://www.history.navy.mil/books/op...000/index.html

http://www.smecc.org/mcmahon's_radars!.htm

rein1705 · 12-22-10, 04:52 PM

Quote:

Originally Posted by Arael

On the subject of the S-Boats, what is that funny little ball that's sticking up out of the deck near the bow?

That my friend is the sonar sound head.

Elektroniikka-Asentaja · 01-13-11, 02:50 PM

This is very simple question that may have been asked before but I'm lazy and didn't want to search whole thread.. And now someone can feel useful when he tells me:

Was it possible to use diesel engines in WWII submarines when they were submerged? As we all know it is not an option in SH4 and I'm not very good in submarine history (Although reading trough this thread I bet that I'd know more about submarines than anyone in my town..)

I just wondered that because how would they pump out exhaust gases? And if they had a hole for that in the boat how didn't the water come in?

(Also isn't CO2 lighter than air right? Why didn't they pump exhaust gases to air tanks if they were short on compressed air if those gases would have worked even better?

Yea, perhaps I'll let submarine building to engineers who know what to do

)

Happy hunting everyone!

PS question: Just came in my mind from that salute smiley, did submarine captain really do that much work as we do in SH4 or did those lieutenants and petty officers etc. do their own choices for example in shooting torpedos if and when captain was sleeping or something?
...yes I know that captains weren't sleeping during convoy/Task Force attacks but anyway...

Gargamel · 01-13-11, 06:27 PM

Without a snorkel, no, subs could not run their diesel's underwater. The engines would quickly suck all the breathable air from the boat, and replace it with toxic exhaust.

With the addition of a schnorkel, subs could run their diesels while submerged, but only very shallow. The pipe was much larger than a periscope, and therefore easier to detect, so they couldn't use it when approaching ships to attack.

CO2 is heavier than Oxygen and Nitrogen, which are the main components of 'air' (21% and 76% respectively), while CO2 is a component of 'air' (about 2%). So yes, CO2 would settle lower in the boat, but it wouldn't take long for it to fill up. Using compressed air to vent the boat worked a little, but you didn't want to waste the compressed air, as you needed it for driving the boat. Also, in order to vent the air, and it depended on the system they used, you may have to over pressurize the boat to force the air out, and then you'd compress the sailors too. You'd then end up with the same problems divers face with decompression sickness. That could be avoided with a negative pressure pump, sucking the air out, but it would cause much discomfort if the guy running the valves varied the pressure slightly (Think about driving down a big hill quickly, or in an airplane, having to equalize your ears).

I may be wrong here, as it's just supposition on my part.

Gargamel · 01-13-11, 06:36 PM

Quote:

Originally Posted by Arael

On the subject of the S-Boats, what is that funny little ball that's sticking up out of the deck near the bow?

I have noticed that on a lot of pics of British boats from the 80's and 90's too. I too am curious.

ReallyDedPoet · 01-13-11, 10:54 PM

Quote:

Originally Posted by DaveyJ576

I have spent the last week and a half revising the Wikipedia page on the Gato class submarines. The original was incomplete, misleading, and in some cases completely wrong. I think it will stand the test now. Take a look when you have the chance:

http://en.wikipedia.org/wiki/Gato_class_submarine

Enjoy!

Just seeing this now as well. Very nice

Platapus · 01-15-11, 08:56 AM

Another lubber of land question.

I am rereading Beach's Run Silent Run Deep. If anyone has not read it, I highly recommend it. Beach was a talented writer. I found myself slightly out of breath just reading the first two chapters.

Anyway, about 2/3rds though the book, Beach makes a comment that the Negative Tank, unlike the other tanks is vented directly into the submarine. In the story he relates a circumstance where during an emergency dive, the negative tank was not blown when it should have been and when they blew it at a deeper depth it caused discomfort in the submarine.

Beach is pretty accurate in his books. But is this true?

Negative Tank vents only into the Submarine?

Why? is this to help conceal the submarine during the dive?

It is my understanding/(misunderstanding?) that during a normal dive, the negative tank is flooded, but when the submarine is on the way down, it is blown at a relatively shallow depth. The purpose of the negative tank is to give the submarine that extra kick to get under faster.

By venting the Negative tank into the submarine, there would not be a big sub fart of air telling the enemy where the sub is.

Is this correct or do I need to go back to lubbing land again?

TorpX · 01-16-11, 05:50 PM

I could be wrong but I was under the impression that the negative tank was only flooded when they wanted to go deep fast (i.e. an emergency).

As far as the venting is concerned, I don't know. Your guess seems reasonable though.

I was wrong, the negative tank was routinely used.

This was posted in another thread by Takao: http://www.history.navy.mil/library/online/ss-doc-2.htm

Very interesting.

10-31-10, 08:00 PM	#497
Platapus Fleet Admiral Join Date: Oct 2006 Posts: 19,378 Downloads: 63 Uploads: 0	Ah, so putting a bubble in safety is, in fact, adding a little bit more positive buoyancy to the boat? Would a bubble in safety be put in times where there is no damage? If the trim analysis for a specific dive were to be "Heavy overall and all right fore and aft", would a remedy be putting a bubble in safety to establish the trim? (I love this thread, so much to learn, so many willing to teach) __________________ abusus non tollit usum - A right should NOT be withheld from people on the basis that some tend to abuse that right.

11-13-10, 02:18 PM	#499
kraznyi_oktjabr Sea Lord Join Date: Mar 2010 Location: Republiken Finland Posts: 1,803 Downloads: 8 Uploads: 0	Platabus and Dave, thank you very much for your answers! __________________ You talk to God, you're religious. God talks to you, you're psychotic. - Dr. House

12-08-10, 08:48 PM	#501
TorpX Silent Hunter Join Date: Sep 2010 Posts: 3,975 Downloads: 153 Uploads: 11	Greetings Hello everybody. I've been playing SH 4 for a little while, but am new to the forum. This is a great place and I always learn something here. First, I would like to thank DaveyJ, and all the other Vets, not only for their service, but for the infornation and insights they provide. Second, I have a few questions about the S-boats. Patrol Endurance. How long could they remain at sea? Apart from fuel considerations how much food could they carry? Battery Capacity. How far could they go while submerged? In 1941, were their batteries degraded or had they recieved refits before wartime deployment? Surface Speed. How fast could they go in heavy seas? In SH4 they can plow through rough seas with little problem, but it seems to me this is a game flaw. Thanks in advance.

01-13-11, 02:50 PM	#505
Elektroniikka-Asentaja Loader Join Date: Nov 2010 Location: Hiding from Dowly Posts: 81 Downloads: 3 Uploads: 0	This is very simple question that may have been asked before but I'm lazy and didn't want to search whole thread.. And now someone can feel useful when he tells me: Was it possible to use diesel engines in WWII submarines when they were submerged? As we all know it is not an option in SH4 and I'm not very good in submarine history (Although reading trough this thread I bet that I'd know more about submarines than anyone in my town..) I just wondered that because how would they pump out exhaust gases? And if they had a hole for that in the boat how didn't the water come in? (Also isn't CO2 lighter than air right? Why didn't they pump exhaust gases to air tanks if they were short on compressed air if those gases would have worked even better? Yea, perhaps I'll let submarine building to engineers who know what to do ) Happy hunting everyone! PS question: Just came in my mind from that salute smiley, did submarine captain really do that much work as we do in SH4 or did those lieutenants and petty officers etc. do their own choices for example in shooting torpedos if and when captain was sleeping or something? ...yes I know that captains weren't sleeping during convoy/Task Force attacks but anyway... __________________ Elektroniikka-Asentaja = Electronics Assembler. In finnish, Just in case someone wants to know.. New rig for noisy running: Desktop w/ Asus P5QC motherboard, Intel Core 2 Duo 2,94 GHz processor, ATI Radeon HD 4800 series graphics, 4 GB DDR3 Ram and 1297 GB hard drive memory There is a good possibility that the above post was written with a phone so please forgive the typos

01-13-11, 06:27 PM	#506
Gargamel Lucky Sailor Join Date: Oct 2010 Location: Rome Posts: 4,273 Downloads: 81 Uploads: 0	Without a snorkel, no, subs could not run their diesel's underwater. The engines would quickly suck all the breathable air from the boat, and replace it with toxic exhaust. With the addition of a schnorkel, subs could run their diesels while submerged, but only very shallow. The pipe was much larger than a periscope, and therefore easier to detect, so they couldn't use it when approaching ships to attack. CO2 is heavier than Oxygen and Nitrogen, which are the main components of 'air' (21% and 76% respectively), while CO2 is a component of 'air' (about 2%). So yes, CO2 would settle lower in the boat, but it wouldn't take long for it to fill up. Using compressed air to vent the boat worked a little, but you didn't want to waste the compressed air, as you needed it for driving the boat. Also, in order to vent the air, and it depended on the system they used, you may have to over pressurize the boat to force the air out, and then you'd compress the sailors too. You'd then end up with the same problems divers face with decompression sickness. That could be avoided with a negative pressure pump, sucking the air out, but it would cause much discomfort if the guy running the valves varied the pressure slightly (Think about driving down a big hill quickly, or in an airplane, having to equalize your ears). I may be wrong here, as it's just supposition on my part. __________________ Luck is a residue of Design.

12-20-10, 03:53 PM	#502
Arael Planesman Join Date: Aug 2010 Location: The Mitten Posts: 184 Downloads: 94 Uploads: 0	On the subject of the S-Boats, what is that funny little ball that's sticking up out of the deck near the bow?

01-15-11, 08:56 AM	#509
Platapus Fleet Admiral Join Date: Oct 2006 Posts: 19,378 Downloads: 63 Uploads: 0	Another lubber of land question. I am rereading Beach's Run Silent Run Deep. If anyone has not read it, I highly recommend it. Beach was a talented writer. I found myself slightly out of breath just reading the first two chapters. Anyway, about 2/3rds though the book, Beach makes a comment that the Negative Tank, unlike the other tanks is vented directly into the submarine. In the story he relates a circumstance where during an emergency dive, the negative tank was not blown when it should have been and when they blew it at a deeper depth it caused discomfort in the submarine. Beach is pretty accurate in his books. But is this true? Negative Tank vents only into the Submarine? Why? is this to help conceal the submarine during the dive? It is my understanding/(misunderstanding?) that during a normal dive, the negative tank is flooded, but when the submarine is on the way down, it is blown at a relatively shallow depth. The purpose of the negative tank is to give the submarine that extra kick to get under faster. By venting the Negative tank into the submarine, there would not be a big sub fart of air telling the enemy where the sub is. Is this correct or do I need to go back to lubbing land again? __________________ abusus non tollit usum - A right should NOT be withheld from people on the basis that some tend to abuse that right.

01-16-11, 05:50 PM	#510
TorpX Silent Hunter Join Date: Sep 2010 Posts: 3,975 Downloads: 153 Uploads: 11	I could be wrong but I was under the impression that the negative tank was only flooded when they wanted to go deep fast (i.e. an emergency). As far as the venting is concerned, I don't know. Your guess seems reasonable though. I was wrong, the negative tank was routinely used. This was posted in another thread by Takao: http://www.history.navy.mil/library/online/ss-doc-2.htm Very interesting. Last edited by TorpX; 01-16-11 at 06:42 PM.