Is this a bug?
 

I have been noticing this a lot near land. My sonar is showing hits which extend across land. In this photo below, I was only hundreds of yards from the shoreline, but the sonar shows it is detecting ships on the other side of the land mass.

http://farm3.static.flickr.com/2213/...23ac7404_o.jpg

Unfortunate hard-coding. Your hydrophones (And their's as well) can hear "past" land. Unchangeable.