Mallows Bay is the grave yard of 230 ships (81 wooden) from the US fleet in World War I. Mostly burned and then sunk.
Not recommended for an inflatable kayak but I risked it and came out unscathed. The reason it is not a place for an inflatable is because of the spikes, sharp metal edges and whatever else is down there. The Potomac is alway pretty cloudy water so one must be really careful navigating through the debris. You'll see what I mean in the pictures.
Here are some pictures:

Mallows Bay 1 by dspidaliere, on Flickr

Mallows Bay 2 by dspidaliere, on Flickr

Mallows Bay 3 by dspidaliere, on Flickr

Mallows Bay 5 by dspidaliere, on Flickr

Mallows Bay 4 by dspidaliere, on Flickr

Mallows Bay 6 by dspidaliere, on Flickr

Mallows Bay 7 by dspidaliere, on Flickr