Each marking required by § 183.23 must be -
(a) Capable of withstanding the combined effects of exposure to water, oil, salt spray, direct sunlight, heat, cold, and wear expected in normal operation of the boat, without loss of legibility; and
(b) Resistant to efforts to remove or alter the information without leaving some obvious sign of such efforts.
[CGD 78-034, 45 FR 2030, Jan. 10, 1980]