Hydrophones

[gsgreene]

Does anybody have any info or photos of the hydrophones that extended through the hull under the forward torpedo room? The only info that I find is in the Sonar Operators Manual http://www.maritime.org/fleetsub/sonar/chap1.htm#1A.
I'm currently cutting out the flood ports for the main ballast tanks and safety tanks and scribing the valve covers for the FBTs and Negative Air Tank but I am not sure how to handle the openings for the hydrophones.
I am also looking for photos of the manhole covers for the Normal Fuel Oil Tanks and the Fuel Oil Expansion Tanks.
If anyone could help me, it would be greatly appreciated.
Thanks

[ricknelson]

I used the picture on

I used the picture on Page 5 of the reference Manual you refer to of the two Hydrophones plus the fact that the hull openings are 22" in diameter according to the Gato Docking Plan to model the hydrophones for my USS Grouper I'm building using the Revell Lionfish kit.



The photo is of the hydrophone and all the mounting hardware except for the 22" shaft. You can just see a brass peg sticking out of the top that will be inserted into the vertical shaft. I got a little carried away and made the hydrophones and the pit log retractable so I wouldn't damage them when handling the boat.

I have some drawings I made that I built the hydrophone from that I could scan for you if you like.

[gsgreene]

Thanks for the reply

I would be extremely grateful if you could provide me with any scan that you might have.
I was going through some photos on the navsource website and came across the foillowing which I beleive represents the hydrophone in a deck mounted orientation. I'm wondering if this is the same as what would have been mounted under the hull according to other/previous configurations.

[ricknelson]

I have seen the two

I have seen the two pictures you posted before. However, I have never seen that hydrophone mounted on any other boat. It may be that these two photos were taken of an experimental hydrophone mounted on a test boat. Easier to work on deck but better performance mounted below the keel.

I've attached two drawings I made of the Hydrophones I built for my Grouper, SS-214. As I said before the dimensions are from the figure in the Sonar Chapter of NAVPERS 16160, 1946. I did not include the hardware for making them retractable.

I've also attached some photos of my 1/180 scale hydrophone installation on my Grouper build. You'll also see the Pit Log I implemented.



The hull curvature is a little exaggerated!



Extended


Starboard Side


Retracted


Please excuse the putty I need to clean up. Let me know if you have other questions.

[big jim]

I have seen the two

I have seen the two pictures you posted before. However, I have never seen that hydrophone mounted on any other boat. It may be that these two photos were taken of an experimental hydrophone mounted on a test boat.

Rick,
I believe that I read where the top mount was the position when they first came out with the hydrophones. It was later discovered that it was better to mount them below in part to prevent damage during depth charge attacks.

[ricknelson]

My opinion is that it

My opinion is that it is much quieter acoustically below the hull than above it. The superstructure and the water flowing through it can create a lot of acoustic background noise. I do not believe the "above hull" position was ever adopted because of the lack of photographic evidence. The only prominent "above hull" sonar hydrophone was the JV sonar head and it had a more directional pattern.