In addition to the 133 110-foot submarine chasers in the USN assigned to duties overseas in WWI, there were about 170 assigned to ports along the coasts of the U.S. and Central America. For example, see this photo set on SC 284 in the Canal Zone. SC 107, shown in a recently added photo set, was among those to serve in home waters, assigned to the 6th Naval District. Thanks to Mike Estes, grandson of SC 107 crewman Emmet Monroe Estes, for sending the photo scans to The Subchaser Archives.
Photo: Bow of SC 107.
While the chasers on the east coast of the U.S. did not serve on barrage lines, had the war stretched on for longer than it did, most of them likely would have been sent overseas for that duty. And there was submarine activity on this side of the Atlantic Ocean, as well. Several U-boat attacks occurred off the U.S. coast. A notable example is an incident in which U-117 sank some fishing boats off George's Bank in August, 1918. It then proceeded south, laying mines and sinking other vessels. Chasers were among the vessels sent to hunt for the submarine. (Details on that incident can be found in the U.S. Navy Department publication, "German Submarine Activities on the Atlantic Coast of the United States and Canada," printed in 1920.)
As far as I know, none of the chasers assigned to U.S. bases were directly involved in submarine attacks in WWI, but they were part of the overall force assigned to protect U.S. shores, and served in the overall ASW effort to address the submarine menace.
--Todd Woofenden, editor