Talk:Side-scan sonar

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[edit] Multibeam

When I searched for multibeam sonar, I was redirected to sidescan sonar. These are two separate, though sometimes combined, technologies.

I agree. Multibeam sonar should not direct here, even though there is no page for it. Multibeam sonar is used to accurately measure depth, something that side-scan sonar cannot ordinarily do. Anyone searching for it could be confused by this redirect. —Preceding unsigned comment added by 66.71.40.143 (talk) 01:19, 11 December 2007 (UTC)

[edit] Bridge Picture

Does anyone know how the ferry-bridge got on the bottom of this lake? Was it submerged by the flooding that occurred when the dam was created? Maybe I'm just dull-witted, but perhaps this cool image in the article deserves a word of explanation!? (warren - charanga dot geo at yahoo dot com)

Often times such images are recorded in man made lakes where structures are submerged once the lake is filled. This is most likely the case with the ferry bridge picture.

The picture is a side-scan sonar composite image of Wyse's Ferry Bridge where it sits today at the bottom of Lake Murray (South Carolina). On the right is a picture of what the bridge looked like in 1919 before the lake was built. Lake Murry began construction in 1927 and was completed in 1930. The bridge and several other structures remained and were submerged beneath the lake, most of which are below 100 ft in depth. This bridge is a destination for a number of skilled divers. One of my high-school classmates has dived on the bridge several times and tells me that it is very cold and dark at that depth, but surprisingly visibility is good if you do not disturb any of the surfaces. If you would like to know anything else about this image or Lake Murray, just let me know. I can even tell you about a History Channel episode where a B-25 was raised out of the lake!
-GreyGh0st 03:31, 9 August 2007 (UTC)

[edit] Technical details

I understand that side-scan sonar sends out a ping in a plane and listens for a response, but how does it do this? What shape is the transducer? How can it pick up the source of the echos with high angular accuracy? Naively, I would think that a side-scan sonar system would need the same number of transducers as it has "pixels", kind of like a flatbed scanner. —Ben FrantzDale 18:15, 16 August 2007 (UTC)