ORN Series I Vol. 10:465
The Obstructions
Grant’s forces were supplied by ships coming up the James—whose safety depended on Butler’s
obstructions, depicted in this once-secret chart from September 16,
1864. Facing Richmond (here upriver is to the right) are two command-detonated torpedoes
(mines) that were hidden in the channel with their firing wires
running to a hut on shore. A net stretched across the river in
front of the "Torpedo Hut" to catch floating mines released by the
Confederates. On the left, scuttled ships in the channel are marked
1-14; their masts were cut down and chained into a boom that spanned the river
as well. The chart also
maps
the river's depth, information the C.S. Navy would have
desperately desired.