33 CFR 175.110 – Visual distress signals required
(a) No person may use a boat 16 feet or more in length, or any boat operating as an uninspected passenger vessel subject to the requirements of 46 CFR chapter I, subchapter C, unless visual distress signals selected from the list in § 175.130 or the alternatives in § 175.135, in the number required, are onboard. Devices suitable for day use and devices suitable for night use, or devices suitable for both day and night use, must be carried.
(b) Between sunset and sunrise, no person may use a boat less than 16 feet in length unless visual distress signals suitable for night use, selected from the list in § 175.130 or § 175.135, in the number required, are on board.