It appears to be a WW1 German U-Boat.
The ship in the background appears to be an American Chester class scout cruiser.
I'd guess that it is the U-53 which visited the US in 1916.
http://en.wikipedia.org/wiki/File:German_submarine_SM_U-53.jpg
That would make the cruiser the USS Birmingham which was the Flagship of Destroyer Force Atlantic Fleet, and Torpedo Flotilla 3 at that time (according to Wikipedia)
http://en.wikipedia.org/wiki/USS_Birmingham_%28CL-2%29
It MIGHT be one of the U-boats that was captured and toured the US after the war but I don't think any of the 3 Chesters would be in the picture if that was the case. Also, its hard to tell but the uniforms appear to be German, so I'm gonna stick with U-53.