All I can say about GWX is WOW!!!!
Now about my thread title....
Im currently in my first patrol out of Willemshaven. I was off the East Coast of England... In the AN sector. I submerged to do my hourly Hydro check and I hear this REALLY WIERD sound on the Hydro.. It sounded like a cross of Whale/Dolphin song and an electronic almost Lazer type sound

at 090 deg. I chased it for awhile and it went away....
What the hell is it?