Josh,

WWI was a different war at sea than WWII; the technology and tactics on both sides were more primative. The central struggle was whether Great Britain would be able to import enough material to sustain its population and war effort; the battle was fought pretty close to the shoreline of England (and Wales, Scotland and France) with both sides making heavy use of mines. (About a third of U-boats were minelayers and the number one cause of U-boat loses were mines, either friendly or enemy.) The only other major theater of U-boat operations was the Med, though Germany did build a few \"submarine cruisers\" and ocean-going minelayers.

The concept of \"hunting\" submarines didn\'t really exist either; underwater detection was very primative (i.e. follow that tropedo track to its origin or looking for shadows underwater). Sonar was just being developed in 1918 and did not play an important role in the war. The USN was not a big factor either; the few destroyers and escorts they operated in European waters were a nice addition but hardly decisive; of much greater importance were U.S. supplies and troops shipped to aid England and France. The Germans had no effective answer to convoys, so they lost the submarine campaign and the war.

The U-boat sunk by the USN was U 58 on November 17, 1917. There are a few other cases were USN vessels may have played a role, but these number no more than about four. These generally are cases where the ultimate cause of loss is considered to be unknown.

U.S. losses to U-boats were the armored cruiser USS San Diego (either mined or torpedoed, the U-boat responsible was mined on her way home with no survivors) and one destroyer. In addition, a pre-Dreadnought battleship was damaged.

A list of U.S. merchant ships lost can be found at [www.USMM.org]

A list of all u-boats lost with cause (a few possibly incorrect given recent U-boat wrecks discovered and not included) is at [www.ukans.edu]