Radio Acoustic Ranging - igniting the bomb and timing fuse.
TNT bombs were sound source for RAR.
RAR work on OCEANOGRAPHER
Image ID: theb2255, NOAA's Historic Coast & Geodetic Survey (C&GS) Collection
Location: Georges Bank, New England coast
Photo Date: 1930
Credit: C&GS Season's Report Peacock 1930-83
Category: Charting/Navigation/Electronic/Radio-Acoustic Ranging/
• High Resolution Photo Available