A shipwrecked barge or something under the water??? Just seems to not fit in the image correctly though, just looks out of place. Off of Cape St Claire
It's a blended photo. The object in the original image a barge that was involved in a dredging operation for the channel. Later an updated photo was overlayed, and in it, the channel does not line up. I have transited this channel over 150 times in the past 18 months
http://maps.live.com/default.aspx?v=2&cp=39.049827~-76.428811&style=h&lvl=18&tilt=-90&dir=0&alt=-1000&