Real Submarine Technology & History Q&A

[LukeFF]

Originally Posted by TorpX

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?

Offhand I don't recall, other than that, according to 1939 data, the max range was about 10,000 miles at 8 knots surfaced. Of course, the fuel tanks in these boats were known to constantly leak, so that number could vary significantly.

Battery Capacity. How far could they go while submerged? In 1941, were their batteries degraded or had they recieved refits before wartime deployment?

There was not a lot of funding available for S boats in the 1930s, so their first modernization refits/overhauls typically did not occur until late 1942/early 1943. So yes, in general, the equipment was very old and in need of an upgrade. Submerged speed/range at the outbreak of war in 1939 was 100 miles at 5 knots. Max submerged speed for S-18s was 9 knots and 9.5 for S-42s (again, 1939 data).

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.

Max speed was 13 knots for the S-18 and 12.5 for the S-42. In heavy seas, no doubt it was noticeably less. The S boats were not known for their sea keeping abilities.

[Kruger]

I've read the entire thread today, amazing how much information you have all shared here, thank you all and especially Dave.

Some pages ago you all discussed about the possibility of submarines not having a sail, and that there were even some projects in this direction.

While the hydrodynamics would undoubtedly be increased, I think we should not forget that a sub (even a big one) has a low profile, and consequently it does not ride the waves very well. Therefore in my opinion it would be very hard to operate a sub on the surface in rough weather without a tower.

A modern sub theoretically does not need to sail on the surface, but this possibility cannot be completely ruled out, can it ?

Speaking of which, I wonder what subs did in ww2 in extremely rough weather. Of course, staying submerged saves a lot and avoids the complete mess of not being able to eat something without sticking the fork in your eyes, but they needed to recharge the batteries. How are the storms in the pacific compared to the ones in the Atlantic ?

Dave, could you tell us a little about the procedures aboard a diesel sub in stormy weather ? Do you adopt the maximum possible buoyancy ? Trimming the boat must be a hell of a task.

I can only imagine that in a serious storm you would be completely swept off the bridge (das boot comes to my mind, even though I cannot say how realistic that scene was created) and the boat would just either completely submerge in a big wave, or jump out of the water between the waves.

did I say something dumb ?

[Subnuts]

Quite a few people have asked about late-war US submarine countermeasures, but not much information seems to be available out there. In Thunder Below Eugene Fluckey mentions using a large number of decoys while being hunted by a DD in shallow waters, but not much is actually said about them.

I recently bought a copy of Friedman's US Submarines Through 1945, which includes a few paragraphs on the subject, which I'll post here for anyone curious.

A submarine decoy program began in April 1943. Evolved from ASW training aids (echo repeaters) that the University of California Division of War Research (UCDWR) began to develop in 1942, decoys could be released from a submarine's 3-inch signal ejector tube and from her torpedo tubes. NAC was a barrage jammer with only limited output at any one frequency band. After tests on board an S-boat in February 1944, 450 NACs were ordered in June 1944; that increased to 5,450 in August. Another 5,000 NAC-1s were ordered in June 1945. A total of 4,308 were supplied to the submarine force during the war (contracts were cut back drastically at the end of the war). NAC proved only partially effective against experienced sonar operators. Its successor, NAH, used a high-velocity tape or disk recorder to pick up the sonar ping, then retransmitted it for 15 sec, beginning 0.10 sec after it arrived. It worked over the 10-30 kHz band. Development began in May 1945.

NAC did not move through the water like a real submarine. Work on a self-propelled NAD began in May 1943. The 3-inch NAD-3 simulated a submarine running at periscope depth at 120 turns. It could not accommodate a sonar repeater. A 6-in (diameter) decoy ejector was proposed; beginning in December 1943, an enlarged NAD-6 (6 in x 48 in) incorporating a repeater was designed to fit it. The new ejector was then canceled, and NAD would have to be fired from a torpedo tube. UCDWR enlarged NAD again (the 10-inch NAD-10 was made from an M30 mine body). The first NAD-6, carrying a sonar repeater, was completed in August 1944. BuShips demanded a simulator; a redesigned NAD-6 was tested in October 1944. Contracts for 500 NAD-6s and 500 NAD-10s were let late in 1944 and doubled in 1945; at the end of the war they were cut back to 500 each. These decoys held a straight course within two degrees so that the launching submarine where they were and evade away from them; gyro angle was preset to within plus or minus 90 degrees. NAD-3 ran at 5 kt at a depth of 50 ft and slowed to 3 ft to begin noisemaking at a preset distance. NAD-6 ran out of a torpedo tube at 4 kt; noisemaking began after 35 sec, and lasted 30-35 min. NAD-10 ran out at 7 kt, then slowed to 3.75 kit after 1 min; it lasted an hour. At lease some NADs were in fleet service in the summer of 1945.

David Taylor Model Basin began work in 1944 on NAE, a mechanical noisemaker derived from the towed FXR and effective above 6 kHz. Mk 1, a wideband masker, was field-tested in October 1944 and operational in the spring of 1945. Mk 2, introduced in the summer of 1945, differed from Mk 1 in that it could be launched down to 400 ft and its supporting balloon hovered below the surface of the water so that it was not visible from the air. Mks 3 and 4 were high-frequency maskers and jammers. NAE was considered effective at high sonic and supersonic frequencies and could even jam some sonars, but it was less effective at lower sonic frequencies. Postwar, it was developed mainly as a rocket-fired noisemaker (acoustic torpedo countermeasure) for use by surface ASW ships.

UCDWR and David Taylor conceived the NAG in 1943 as a lower-frequency companion to NAC to counter hydrophones in the 0.1-10 kHz range. A second sound head was later added, so that it could also operate at supersonic frequencies. NAG was under test at the end of the war. There were also false target shells (FTSs) and false target cans (FTCs). MIT designed pepper signals (Mk 14 and Mk 20) to mask submarine self-noise at sonic frequencies in shallow water. Reverberation would add its own masking; in deeper water, sonar operators could maintain contact between explosions.

A combined-use doctrine was quickly worked out. If the submarine was not sure that the enemy had contact, she launched an NAD or ejected FTSs and FTCs. If the enemy had contact, quantities of NACs and NAEs could jam receivers, confuse an attack, and break contact; then FTSs and FTCs would be ejected to add to the confusion. Once contact was clearly broken, an NAD emerging from the masked area would attract attention. The submarine had to choose her evasive course so that the NAD emerged before she did. Decoys always had to be ejected in rapid succession to avoid forming a trail that pointed to the submarine. These ideas and decoy categories (static noise beacon, mobile submarine simulator) have persisted ever since. Analogous radar beacons were developed to decoy radar-directed ASW aircraft. Hopes of an antisonar coating were not realized.

[TorpX]

I'm not sure what to make of all that. I'm guessing none of these complicated devices were modeled in SH4.

[DaveyJ576]

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?

As a few other readers have stated, that is the ball shaped receiver array for the S-boat's JK high frequency passive sonar. Frequently, mounted just below it was a bar shaped array for the SC low frequency sonar. The original shape for the JK was a flat plate. However, water turbulence prevented it from being used at speeds above 5 knots. The Naval Research Laboratory developed the spherical cover. It was so effective it effectively doubled the maximum sonar speed. It was 19" in diameter. The S-18 group had a rated top submerged speed of 9 knots and the S-42 group at 9.5 knots. So this simple spherical cover allowed the use of the sonar up to the maximum speed of the boat.

[DaveyJ576]

Originally Posted by Platapus

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?

Platapus:

You answered all of your own questions, and accurately I might add! When surfaced, the negative tank is kept full (or nearly so depending on the calculated state of the boat's buoyancy). You do this for the very reason you mentioned: it provides that extra amount of negative buoyancy needed to submerged the boat fast on a crash dive. Once under, the tank is blown to a pre-calculated "mark" that will restore (when combined with adjusting the amount of water ballast in the trim tanks) the desired neutral buoyancy. If circumstances prevented you from blowing the tank at periscope depth, you would obviously have to use increasing amounts of air pressure to empty the tank the deeper you were at the time. You eventually have to vent this air if you want to refill the tank and the air has to go somewhere. Venting it over the side would give off telltale bubbles so it is vented inboard. This would raise the internal air pressure and after a while this gets very uncomfortable for the crew.

BTW, Ned Beach wrote two sequels to "Run Silent, Run Deep", and are both excellent reads in their own right. "Dust on the Sea" picks up where the first book leaves off and completes the WWII portion of the trilogy. "Cold is the Sea" jumps to the Cold War era and follows Richardson after his promotion to a nuclear submarine squadron commander and deals with a Soviet submarine incursion to the Arctic.

Beach wrote the original RSRD in his off time while serving as a naval aide to President Eisenhower. It was a best seller and turned Beach into a semi-celebrity while still serving in the Navy. He also wrote several non-fiction books, one of his best being "The Wreck of the Memphis". This is the story of his father's command, the armored cruiser USS Memphis (ACR-10) and how it was wrecked by a freak tsunami while in harbor in the Dominican Republic. This was a gripping, thrilling tale and Beach did a masterful job of writing. I highly recommend any of this books.

[sharkbit]

Originally Posted by DaveyJ576

Platapus:


BTW, Ned Beach wrote two sequels to "Run Silent, Run Deep", and are both excellent reads in their own right. "Dust on the Sea" picks up where the first book leaves off and completes the WWII portion of the trilogy. "Cold is the Sea" jumps to the Cold War era and follows Richardson after his promotion to a nuclear submarine squadron commander and deals with a Soviet submarine incursion to the Arctic.

Just curious-What do you think of Beach's accuracy?

I always felt they were extremely detailed and accurate, as well they should be considering his service. His narrative of approaches and attacks, especially in "Dust on the Sea", seem extremely detailed and very realistic. I've learned a ton just from those books as opposed to the 30 second approaches depicted in movies or the glossed over attacks in some books.

I'll definitely second your recommendation on the trilogy . I've read all three countless times. In fact, I had to replace my copy of "Dust on the Sea" last year-it was falling apart. "Run Silent, Run Deep" isn't to far from falling apart as well.

[DaveyJ576]

Originally Posted by Kruger

Speaking of which, I wonder what subs did in ww2 in extremely rough weather. Of course, staying submerged saves a lot and avoids the complete mess of not being able to eat something without sticking the fork in your eyes, but they needed to recharge the batteries. How are the storms in the pacific compared to the ones in the Atlantic ?

Dave, could you tell us a little about the procedures aboard a diesel sub in stormy weather ? Do you adopt the maximum possible buoyancy ? Trimming the boat must be a hell of a task.

I can only imagine that in a serious storm you would be completely swept off the bridge (das boot comes to my mind, even though I cannot say how realistic that scene was created) and the boat would just either completely submerge in a big wave, or jump out of the water between the waves.

A modern nuclear submarine can obviously go deep and ride under any storm, as long as the water is deep enough. When the boat is at deep submergence, there is very little sensation of movement. It feels very much the same as sitting alongside the pier.

How deep you would have to go to avoid a storm would obviously depend on how strong the storm is. I have been at 150 feet and could still feel the effects of the wave action, although it was greatly reduced.

Diesel boats are a whole other story. When submerged, diesel boats run on batteries, which will be depleted in fairly short order. A USN fleet boat could run for about 15-18 hours at three knots on the battery, assuming the battery was new and fully charged upon diving. This may actually sound like a long time, but remember that is at three knots, which is three nautical miles per hour, a distance of about 6000 yards in an hour. The average person can walk faster than that. If you go faster to cover a greater distance, the battery depletes it's charge faster. At a flank bell the battery will be completely drained in an hour, and you will still only have moved about 8-9 nautical miles.

What am I getting at? Well, the limited speed and endurance of your average diesel-electric submarine while submerged precludes diving to ride out the storm. Therefore your only option is to ride it out on the surface! This is not a pleasant experience. The low height, low freeboard, and the rounded hull shape all make for a very rough ride in heavy seas. Blowing or pumping out ballast to make the boat ride higher is actually counterproductive; it raises the center of buoyancy and results in the boat rolling even worse. It is not uncommon for a fleet boat to take "green water" over the bridge, that is for the boat to go completely submerged for short periods while it rides up and down on the waves. In these circumstances you would have to close the bridge hatch or the conning tower will flood. The lookouts and bridge watch would have to be lashed to their stations to prevent being washed over the side. In many cases the Officer of the Deck (OOD) would send the lookouts below for safety sake. Only the OOD and the Quartermaster would remain topside.

Inside the boat conditions get bad. Walking is very difficult and food and dishes go flying. Usually the cooks will secure the galley and provide only sandwiches for the crew. The best part of the boat to be in is right in the center in crew's mess. Due to it's location in the center it is moving the least. The worst areas are the forward and after torpedo rooms. Being at the very ends they are moving the most and riding out a storm in those compartments is like riding a roller coaster. It will make all but the most salty of sailors seasick. No one sleeps and trying to keep your balance and constantly holding on is actually quite exhausting and the crew gets tired quickly.

Another factor is the location of the main air induction valve for the diesel engines. On a fleet boat it is directly aft of the conning tower and just above the main deck. Low to the water, it will have a tendency to take in water during rough weather and the engine rooms bilges will fill up quick, requiring constant pumping with the drain pump. You also run the possibility of flooding the engines through the intake manifolds and if that happens you will have dead engines and the makings for a very bad day.

On December 3rd, 1943 the USS Sailfish (SS-192), under the command of LCDR R.E.M. (Bob) Ward surfaced into the teeth of a typhoon off the coast of Japan and commenced an attack on a Japanese task force. The seas were "mountainous" and the wind was estimated to exceed 50 knots. His approach was hazardous as any attempt at speed caused the bridge to take green water. The presence of escorts forced him to make several attacks, some submerged and some surfaced. Depth control at periscope depth was nearly impossible in the seas; he was alternately completely submerged with the scope under the water, or broached and on the surface. In desperation he submerged to 90 feet where depth control was a little easier and commenced a sonar approach. But the rough seas again botched his approach and the target passed astern. Angry in his belief that he had lost out on sinking a carrier, it wasn't until later that he and the crew learned that their earlier attacks had been successful. The carrier Chuyo had been mortally wounded and did indeed sink.

The Pacific can host some pretty awesome storms. In 1986 on a run from Japan to the Philippines, my old Darter ran through two separate typhoons. We lost one of our topside sonar domes and the aft marker buoy broke loose. One of the worst spots is the Bashii Straits north of Luzon. The bottom shallows compared to the surrounding seas and this magnifies the wave action. There were several times that we secured the bridge watch and brought everyone below. We raised the snorkel mast so that the main induction was above the waves and we ran along on the "surface", but in submerged mode. We did go deep every once in a while to give the crew a rest, but would eventually have to come back up to charge batteries.

I have spent my entire Navy career in either the Pacific, the Gulf of Mexico, or the Persian Gulf so I can't directly comment on the conditions in the Atlantic. But some of my shipmates have and their stories of the north Atlantic storms are the stuff of legends.

[DaveyJ576]

Originally Posted by sharkbit

Just curious-What do you think of Beach's accuracy?

The accuracy of his novels is top notch. Beach is an incredible writer and his narrative brings everything to life without overwhelming you with technical minutiae.

Beach and most of the other good authors will sometimes downplay the technical side because of the necessity of writing for a wide audience, an audience that may not know the difference between a TDC and an SJ. Beach did a great job of balancing the somewhat conflicting desires of writing a technically and historically accurate novel while at the same time appealing to a wide and only partially informed audience.

The ultimate edition of RSRD is in the U.S. Naval Institute's Classics of Naval Literature series. It is a finely crafted hard bound edition and should last for decades. It comes with a ribbon page marker. "The Wreck of the Memphis" is also available in this series. I have both books and they are true treasures of my collection. See this link for more info:

http://www.usni.org/store/books/clas...ilent-run-deep

[Platapus]

Originally Posted by DaveyJ576

You answered all of your own questions, and accurately I might add!

Thank you for your kind words. I try to figure things out before posting here. I greatly appreciate your contributions to this thread. You give the straight poop and your are patient with lubbers like me.

This is one of my favourite threads on this site.

[Sgt Hotcliff]

Hey mates!

just want to say I just found this thread and will have trouble playing SH4 now, with all this info to read!

Also found an interesting Manual of Mk14 and 23 Torpedoes at
http://www.hnsa.org/doc/torpedo/index.htm

Thk's
Hotcliff

[sharkbit]

I don't know if this has been asked yet, but...
Were torpedoes able to be reloaded while on the surface or did they normally dive to reload?

I've never read anything definitive but I've gotten the impression that they could be in calmer seas.

I would think in seas that were even a little rough, it would be near impossible and extremely dangerous.

In game, I've always tried to limt my reloading to calmer seas(under 10 m/sec wind) and not while going balls to the walls around convoys and such. I try to wait until I'm submerged or I'm away from the action and I can slow down to do it.

Thanks.

[Rip]

Originally Posted by DaveyJ576

The accuracy of his novels is top notch. Beach is an incredible writer and his narrative brings everything to life without overwhelming you with technical minutiae.

Beach and most of the other good authors will sometimes downplay the technical side because of the necessity of writing for a wide audience, an audience that may not know the difference between a TDC and an SJ. Beach did a great job of balancing the somewhat conflicting desires of writing a technically and historically accurate novel while at the same time appealing to a wide and only partially informed audience.

The ultimate edition of RSRD is in the U.S. Naval Institute's Classics of Naval Literature series. It is a finely crafted hard bound edition and should last for decades. It comes with a ribbon page marker. "The Wreck of the Memphis" is also available in this series. I have both books and they are true treasures of my collection. See this link for more info:

http://www.usni.org/store/books/clas...ilent-run-deep

That is the version I have, and I got it for a song on amazon. My first try to get it resulted in finding out the book store didn't actually have it anymore. But like Mush I was persistent and got the *%#*% thing eventually. To be passed on to my son when he is old enough.

[TorpX]

Originally Posted by sharkbit

I don't know if this has been asked yet, but...
Were torpedoes able to be reloaded while on the surface or did they normally dive to reload?

I've never read anything definitive but I've gotten the impression that they could be in calmer seas.

I would think in seas that were even a little rough, it would be near impossible and extremely dangerous.

In game, I've always tried to limt my reloading to calmer seas(under 10 m/sec wind) and not while going balls to the walls around convoys and such. I try to wait until I'm submerged or I'm away from the action and I can slow down to do it.

Thanks.

I have had the same view of this as you.

However, I am reading Thunder Below!, and during their 10th war patrol, he comments on this issue. Fluckey planned out an attack on a well escorted convoy in very bad weather, 40 kt. winds. He said the plan was to reload on the surface, but the torpedo room crews would probably need some help. He was obviously concerned about it; the potential for injury, and told the crew to let him know if they were wallowing around too much.

[DaveyJ576]

When the USS Nautilus (SSN-571) first went to sea for exercises with the fleet in 1955-56 the incredible performance advantage she enjoyed over a conventional diesel-electric GUPPY boat shocked many naval strategists. The sudden realization that she nearly rendered all existing anti-submarine warfare (ASW) techniques obsolete hit the establishment like a ton of bricks. A conference was called together in the late summer of 1956 at Nobska, Massachusetts to study the problem. One of the main issues the attendees tackled was how to hunt and destroy a high speed, high endurance, deep diving nuclear submarine.

One of the solutions they came up with was (predictably for the 1950's) to nuke it. A developmental outgrowth of the Nobska study was the Mk 45 ASTOR (anti-submarine torpedo). With an 11 kiloton yield W34 fission warhead, the Mk 45 would overcome the limitations of the existing sonar and tracking systems and largely negate the speed and depth advantages of a nuclear submarine through good old fashioned brute force.

The Mk 45 was a 19 inch diameter swim out weapon that was 19 feet long and weighed in at a 2300 lbs. It was an electric torpedo of a relatively simple design. It had a range of approximately 7 nautical miles (14000 yards) and ran at a speed of 40 knots. It had no internal guidance or sonar systems other than a gyro. It was guided to the target via a control wire back to the firing sub. U.S. nuclear weapons doctrine of the day dictated that the weapon could not be allowed to auto-burst via it's own systems. It had to be detonated by the firing sub's crew at the appropriate moment (hence the control wire). The 11 kT warhead had a hard kill radius of 8000 yards. In other words, if your target was within that radius when the weapon detonated, it was dead, no joke. At 12000 yards the weapon could still be lethal, although the probability of a kill dropped quite a bit. At 16000 yards the target stood a reasonably good chance of surviving. It entered service in 1963 and was finally retired for good in the 1979 as the highly capable Mk 48 came on line.

There was a bit of gallows humor amongst the submarine crews that carried this weapon to sea. It was said you were assured of two kills anytime you used a Mk 45, your target and yourself. Remember that in the early 1960's the vast majority of the USN submarine force was still made up of diesel-electric GUPPIES and the new Tang, Darter, and Barbel class diesel "fast" attack boats. The maximum speed of these boats varied between 15 and 18 knots. At those speeds the battery would be completely dead in about a half hour. The concern was that if you fired a Mk 45 at an enemy it would be virtually a suicide shot. You wouldn't be able to get away from it fast enough to survive the detonation of your own weapon.

The hard kill radius of the weapon was 8000 yards, with a good probability of a kill out to 12000 yards. Let's assume best case scenario and say you obtain a firing solution on your target at 14000 yards. You fire your Mk 45 and she is running to your target at 40 knots. It will take about 10 1/2 minutes for the weapon to run that far. You can't maneuver and run away to increase the range. Remember the weapon has no internal sonars or guidance, you have to guide it to the target with your boat's own sonars, meaning you have to keep pointed at the target and stay slow and quiet. You send the command for the weapon to burst when it hits the calcuated range of 14000 yards and you wait for the shock wave to hit, fingers crossed.

Accurately tracking a submerged target at 14000 yards was problematic at best in those days. You wanted to rely on passive sonar so that you wouldn't give away your presence with active sonar pings. This made accurate ranging very difficult. Tracking ranges of 9 to 11000 yards were more realistic, and often it was less than that. This gave you precious little room for error when using this weapon. Later advances in sonar increased detection and tracking ranges and made the use of the Mk 45 a bit safer, but the submarine crews never really liked it and always viewed it with a great deal of justified trepidation. No one was sad to see it go when it was finally pulled from service.

If you want to see a Mk 45 torpedo, the USS Torsk (SS-423) museum has one on display on board the boat in Baltimore, Maryland, minus the warhead of course! The Torsk herself never carried the Mk 45 while in service as she did not have the proper sonars or fire control systems.