U.S. Sonar

[Rose]

Ach! This has really been bugging me, and I'm sure it's been answered MANY times before, but I need some education in the topic of US sonar:

I know the Germans used hydrophones as their source of "ears" for the ship, but what did the US use? It is my understanding that there was a retractable sonar antenna on the bottom of the hull fore of the conning tower. Did the sound op. just send out pings periodically, and see if he picked up anything? Wouldn't this give away their position to enemy ASW shipping? It is also my understanding that the Japanese used active sonar pings, thus giving their position away to US subs, so wouldn't it be wise of the US to use other means of sonar? Thanks :D

-A confused sailor

[DeepSix]

I think U.S. subs used passive or "hydrophones" also. They had an active sonar, but I don't think it was used because it was detectable. Don't know about retractable sonar, though; I think the U.S. listening apparatus was up in the bow (but am not sure). I read in Blair about boats that, for various reasons, hit bottom or ran aground and, as he puts it, "wiped off" the sonar heads.

As the war went on, U.S. boats got various radar sets, and apparently these were extremely popular.

[Rose]

Thanks for the answer. We're talking about the same things with the sonar on the bottom of the hull fore of the conning tower. And I just read about the types of RADAR for the US. There was SD Aircraft Sweep RADAR throughout the war for detection of...well... aircraft. The SD Surface Sweep RADAR was developed later ('43? everything technologically advanced seems to happen in '43) in the war for use in detecting surface ships.