Y gun
Also found in: Wikipedia.
Y gun
[′wī ‚gən] (ordnance)
Two-barreled, antisubmarine gun shaped like the letter Y, used to throw depth charges to either side of the stern of the vessel on which the gun is mounted.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.