Did Gemans invent...

[NightCrawler]

Hydrophone? if yes , did the Americans had there own hydrophone, or they copy that when they capture a german U boot?

[Yoriyn]

I read somewhere that the british invent hydrophones to protect convoys from german u-boats in WWI and germans copy british idea in WWII. Don't think americans invent hydrophone, even Blair in Silent War point that the america was far behind europe before WWI in submarine/anti-submarine weapon.

[Tonga]

Regarding hydrophones, I think the Brits were pretty innovative since they already had this technology in WWI and then later refined it to what came known as the ASDIC or active sonar. If I remember it correctly, it was even Rutherford (the guy who is famous for his nuclear research) who invented the hydrophone. Sounded a bit odd to me in the first place, but that's probably why I remember his name in connection to hydrophones.
Concerning ASDIC however the story is a different one. The British had improved their technology and had ASDIC even when WWII started - however it was still rather ineffective, had some flaws and was then greatly improved during the war - necessity is the mother of invention. However they gave this technology to the US for free when WWII broke out and both countries then conducted further research on that basis. Wouldn't deny though that the US had their own hydrophones by that time, and if not, they then definetly got it from the Brits.

The British developed the hydrophone during WW1, Von Hesse is correct, one of the key individuals involved was Nobel prize winning physist Ernest Rutherford. Rutherford developed a piezoelectric device that converted sound into an electrical impulse which could be used to create a visual trace of the sound on paper.

By the end of WW1 hydrophones had been widely fitted to ships as small as ASW trawlers and fixed hydrophone arrays had been planted in the Channel to detect transiting submarines. These were the direct forerunners of the Cold War SOSUS arrays placed in the Atlantic and Pacific.

Contrary to popular myth there was no Anti-Submarine Detection Investigation Committee and the fiction that there was gave ASDIC it's name for the same reasons that tanks were first called Tanks, as a deception to camouflage the true function. See Hackman's Anti-Submarine Warfare in the Royal Navy 1914-54.

I believe that the RN shared hydrophone technology with the USN from the winter of 1918 since the former got a big slice of the escort duties in the Atlantic. The first operational ASDIC set did not go to sea until 1920 or so.

[NightCrawler]

So the British came up with hydrophone, and the German use it against them?
Because Hydrophone had a longer range than Sonar.. so the German knows who ever is nearby than the Destroyer....

Specially in early years 39, till the Sonar pops up...

Another question that i stated, what and how did the Americans check underwater when there is a ship nearby? do they pop the scope and look around every 30 minutes?
Or they have there own kind of hydrophone, after all the British invent the hydrophone, and don't want to share with the Americans???

OT,
I know Germany invented V1, V2 rockets, and rocket-fuel, and Jetplanes(Messerschmitt Me 262)
And for the American lucky to bring over Wernher von Braun, to continue making rockets for the NASA....

[Yoriyn]

Submarine in WWI and WWII was more surface ship with ability to dive. So all submarines was sailing at the surface and dive only when needed. I don't think they have other metod in WWI then scope and listen underwater sounds without any devices.

[CCIP]

Originally Posted by NightCrawler

So the British came up with hydrophone, and the German use it against them?
Because Hydrophone had a longer range than Sonar.. so the German knows who ever is nearby than the Destroyer....

Let's not confuse the terminology and function too much. The difference you're suggesting here is between hydrophone aka. passive sonar, versus ASDIC aka. active sonar. The two have very different methods of detection, although fundamentally both do use sound waves and piezo-electrics to do their job. They are crucially meant to be used in a way that's complimentary.

Nearly all escorts you encounter are equipped with passive sonar/hydrophone, and they're listening just as carefully as you are. Just that the sub can generally afford to be a lot quieter than surface warships, and being far away from the "messy" surface waves does help clarity and range for hydrophone contacts. However this does not mean that surface escorts wouldn't be listening. Now, it's useful as long as whatever you're hunting is making a sound. As soon as it stops - you're kind of on your own there...

Active sonar, on the other hand, can detect large objects irrespective of the noise they're making. These can be also mounted on anything, but for obvious reasons the WWII submarine is not best-advise to emit the loud sounds needed by active sonar to work, because they'll be picked up by those hydrophones that ASW ships are listening for you with.

The submarine always has an advantage in terms of acoustic stealth, but not because of its hydrophones being superior. You can more or less assume that enemy ASW ships will have the same kind of hydrophones as you. It's mainly because the submarine is a quiet platform in normal modes of operation that you have advantage - yeah, you'll hear those escorts first, not because your "hearing" is better because they sail faster and make a heck of a lot more noise than you do. And there's not much they can do about that except outright stop. Which was by the way a tactic used by persistent sub hunters.

Otherwise, at the start of WWII, hydrophone capabilities weren't too far apart between nations. These were a well-established technology, and at least on submarines, did not really evolve much until after the war, when passive sonar operation became a much finer art. The german U-boats maybe had a slight edge, but it was mostly because of the number and quality of 'mics' in their hydrophone arrays, and their cleverly overlapped use of two different different sets of sensors on the top and bottom side of the boat for listening (the GHG and KDB). Everyone else had reasonably good hydrophones available though, both for submarines and ships hunting them.

As far as the Americans, aside from generally operating near the surface or on the surface, there were a few advantages they had. Firstly, US subs' hydrophones consisted of rotatable 'mics' mounted on the bottom of the sub. In theory, they worked on the surface, though in practice the sub needed to be both running slowly and in reasonably calm seas for that to work. Otherwise they certainly had listening capability approaching that of Germans.
But the real strength for the American subs was their radar, which among other things could be operated from periscope depth. The US subs relied extensively on their radars, rather than acoustics, for detecting enemy ships. This is something Germans were far behind in, and unlike the US subs, U-boats never received effective radar capability in any numbers.

Originally Posted by NightCrawler

So the British came up with hydrophone, and the German use it against them?
Because Hydrophone had a longer range than Sonar.. so the German knows who ever is nearby than the Destroyer....

Specially in early years 39, till the Sonar pops up...

Another question that i stated, what and how did the Americans check underwater when there is a ship nearby? do they pop the scope and look around every 30 minutes?
Or they have there own kind of hydrophone, after all the British invent the hydrophone, and don't want to share with the Americans???

OT,
I know Germany invented V1, V2 rockets, and rocket-fuel, and Jetplanes(Messerschmitt Me 262)
And for the American lucky to bring over Wernher von Braun, to continue making rockets for the NASA....

Actually hydrophones = passive sonar. ASDIC = active sonar.

Only US Fleet Boats could cruise submerged using air search radar (SD), surface search radar (SJ) and periscopes for target and threat detection, something not even a Type XXI could do. This in addition to passive and active sonar. The British did share hydrophone/sonar technology with the USN in the early years but American electronics made their sets smaller and generally more reliable.

American Robert Goddard invented the liquid fueled rocket without which the V2 would have been impossible. Von Braun was probably luckier since the agency that he was responsible for made much use of slave labour from concentration camps. Had he not been whisked off the the USA he may very well have ended up in the Soviet Union or Spandau prison for crimes against humanity.

A serving RAF officer named Frank Whittle developed the turbo jet engine at the same time as German university student Hans von Ohain. The German's flew the first jet powered aircraft but the British were close behind and Whittles' design was superior to Ohain's in many respects.

The German navy's active sonar was inferior to the RN sets in most respects from the start but German passive sets (hydrophones) were first class.

[CCIP]

It's also worth mentioning that hydrophones were never a primary detection method for submarines in WWII. Everybody at the start of WWII relied on submarines to hunt down their prey by first spotting it on the surface, either by periscope or by lookouts on the bridge. This was especially true of the Germans, and all their successful tactics (most notably the wolfpack) relied on submarines being able to keep visual contact with their prey, without diving.

Americans pioneered the use of radar, and it was very much the primary means of detection for their submarines through the later half of the war.

Sonar as such came into its own with the advent of true submarines after WWII. Once it became clear that subs would never be able to rely on being able to sneak up on a target through visual contact on or near the surface (because radars could pick up not only surfaced subs, but even periscopes sticking out) or radar (with the advent of effective RW receivers that would make sending radar signals towards your target as attention-drawing as sending loud pings of sound towards it), sound detection became the only viable means for them to work. Then things got really fancy with sonar, even though most of the basic principles of how it works remained essentially the same - it was mostly the depth and versatility of tools for analyzing sounds picked up by the sub's hydrophones that changed, along with ever-improving quality of microphones. However until that kind of sophistication made them important, basic hydrophones were really only of secondary importance to subs.

Originally Posted by CCIP

It's also worth mentioning that hydrophones were never a primary detection method for submarines in WWII. Everybody at the start of WWII relied on submarines to hunt down their prey by first spotting it on the surface, either by periscope or by lookouts on the bridge. This was especially true of the Germans, and all their successful tactics (most notably the wolfpack) relied on submarines being able to keep visual contact with their prey, without diving.

With all respect I don't think that is entirely accurate since as I understand it, American pre-war submarine doctrine included provisions for submerged detection, approach and attack by passive sonar alone with active sonar just used for getting the final bearing and firing range.

The problem was that without the computer support for solving the target motion analysis problems that were developed post-war, the technique was theoretically sound but practically useless. As far as I know not one submerged sonar attack was successful, at least in the Pacific.

[CCIP]

Originally Posted by Randomizer

With all respect I don't think that is entirely accurate since as I understand it, American pre-war submarine doctrine included provisions for submerged detection, approach and attack by passive sonar alone with active sonar just used for getting the final bearing and firing range.

The problem was that without the computer support for solving the target motion analysis problems that were developed post-war, the technique was theoretically sound but practically useless. As far as I know not one submerged sonar attack was successful, at least in the Pacific.

Ah yeah, fair enough, I had heard of that, although this is why I also point out "successful german tactics" in the same paragraph later. I'm definitely talking about practice more than theory - a tactic in the books doesn't mean a successful tactic. I don't doubt that theories about making submerged-only approaches have been floating around since sonar was first invented, and might have even been in doctrine and on the books. However like you say, without more sophisticated TMA among other things, these were not a practical success.

I'm sure many a useful contact was picked up by hydrophone first, too. But all in all, I think all successful uses of WWII-era large submarines capitalized on them being able to survey the surface by eyeball or radar. As soon as they were unable to do that (like u-boats were unable to do once the Allied radar got sophisticated and widespread enough), these submarines became instantly obsolete along with their whole doctrine. Attempts to work around that with things like snorkels were marginally successful at best.

Originally Posted by CCIP

...this is why I also point out "successful german tactics" in the same paragraph later. I'm definitely talking about practice more than theory - a tactic in the books doesn't mean a successful tactic. I don't doubt that theories about making submerged-only approaches have been floating around since sonar was first invented, and might have even been in doctrine and on the books. However like you say, without more sophisticated TMA among other things, these were not a practical success.

This is very true and one should never forget that military theory all too often fails when confronted by military fact. According to RN pre-war ASW theory, ASDIC rendered the submarine essentially harmless. How did that prediction turn out for them?

[NightCrawler]

So, that's means that German U-boots are far advantage than the American submarine i mean in 1939?

I think Germans was pretty advantage not only in U boots, but also in planes, machine guns, tanks.

Even if you want to compare with VII class and Gato or Class SS33...

I think VII class u boots are tights, compare with the Gato class, nice and spacey...

please correct me if I'm wrong.

[Yoriyn]

You right.

But pacific war do not force americans to build smaller submarines. The bigger distances between the patrol-home and weaker japanese ASW tactic give them bigger construction tolerance ratio.

From the other hand WWII is a example when quantity is more important then quality.

Originally Posted by NightCrawler

So, that's means that German U-boots are far advantage than the American submarine i mean in 1939?

I think Germans was pretty advantage not only in U boots, but also in planes, machine guns, tanks.

Even if you want to compare with VII class and Gato or Class SS33...

I think VII class u boots are tights, compare with the Gato class, nice and spacey...

please correct me if I'm wrong.

My take is that it is futile to compare the 1939 U-Boat waffe with the submarine force of the USN. There only similarities is that both used diesel-electric submersibles designed to perform certain duties.

The former was created specifically for war on commerce and in the North Atlantic. All equipment, doctrines and training focused on that operational goal. When war came, they were ready and subject to politically imposed restrictions that eventually fell away, were generally able to fight the war that they had prepared for. When the U-Boats had to act in conjunction with the surface forces as in Norway during 1940 and in support of the Bismarck sortie and with surface forces in the Arctic, they can be judged an epic failure as is only reasonable to expect.

The USN's submarine force was trained and equipped to act in concert with the Battle Force's aim of fighting and winning a decisive battle using battleships supported by aircraft carriers. Their role was scouting and their targets exclusively enemy warships. Hence the large long-ranged, fast and well armed Fleet Boat had evolved to fill this particular tactical niche. America had totally rejected commerce war using submarines, the U-Boat campaign in 1917 had brought the USA into WW1 and in 1939 acting in a like manner was unthinkable. Pearl Harbor changed all that and over night the US submarine arm had to switch gears and fight the kind of war that was unanticipated and for which they lacked even basic doctrinal and training preparation.

It says a great deal for the overall flexibility of the USN that they were able to become as effective as they were, despite huge and painful errors of which the 1941-43 MkXIV torpedo crisis was only one. The Fleet Boats proved to be superb commerce destroyers in the vastness of the Pacific. Had the USN gone the route of the KM pre-war (and there were some on the Navy General Board who advocated smaller submarines), the story of the only successful unrestricted submarine campaign may have been written differently.

Many people around here like to compare the Type VII with the Fleet Boats but they are similar only in that they represented what their respective navy's considered to be the ideal weapon for their specific tactical role. The only U-Boat that was similar in size and capabilities to the Fleet Boat was the Type IXD2 U-Cruiser and it was inferior in speed, torpedo armament and habitability.

As for pre-war aircraft, it is good to remember that with only a few exceptions, every USAAF aircraft was a pre-war design. Thunderbolt, Mustang, Hellcat, Avenger, Lightning, B17, B-29, B-24, B-25, B-26, Dauntless and others, all pre-war designs and all equal or superior to anything of pre-1941 design flown by the Luftwaffe.

Can already feel the flames approaching for posting this so it's on with the NOMEX and apologies for droning on...