[Code of Federal Regulations] [Title 46, Volume 7] [Revised as of October 1, 2003] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR197.458] [Page 436] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 197--GENERAL PROVISIONS--Table of Contents Subpart B--Commercial Diving Operations Sec. 197.458 Gages and timekeeping devices. The diving supervisor shall insure that-- (a) Each depth gage and timekeeping device is tested or calibrated against a master reference gage or time-keeping device every 6 months; (b) A depth gage is tested when a discrepancy exists in a depth gage reading greater than 2 percent of full scale between any two gages of similar range and calibration; (c) A timekeeping device is tested when a discrepancy exists in a timekeeping device reading greater than one-quarter of a minute in a 4- hour period between any two timekeeping devices; and (d) Each depth gage and timekeeping device is inspected before diving operations are begun.