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.:salute:


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

1. Patrol Endurance. How long could they remain at sea? Apart from fuel considerations how much food could they carry?
2. Battery Capacity. How far could they go while submerged? In 1941, were their batteries degraded or had they recieved refits before wartime deployment?
3. 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.

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

Tech jargon
 

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


:salute:

That my friend is the sonar sound head.

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? :hmmm:

(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? :D Yea, perhaps I'll let submarine building to engineers who know what to do :har:)

Happy hunting everyone! :salute:

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...

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.

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

Just seeing this now as well. Very nice :up:

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?

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.

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.



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).

Quote:

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.

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.

:88) did I say something dumb ?

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.

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

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.

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.

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 :yeah:. 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.

:)

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.

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

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.