46 C.F.R. § 127.430 – Visibility from pilothouse.

(a) Windows and other openings at the pilothouse must be of sufficient size and properly located to provide adequate view for safe operation in any condition.
(b) Glass or other glazing material used in windows at the pilothouse must have a light transmission of at least 70 percent according to Test 2 of ANSI Z26.1, “Code for Safety Glazing Materials for Glazing Motor Vehicles Operating on Land Highways,” and must comply with Test 15 of ANSI Z26.1 for Class I Optical Deviation.