33 CFR 175.15: Personal flotation devices required.

Except as provided in §§ 175.17 and 175.25:

(a) No person may use a recreational vessel unless—

(1) At least one wearable PFD is on board for each person;

(2) Each PFD is used in accordance with any requirements on the approval label; and

(3) Each PFD is used in accordance with any requirements in its owner's manual, if the approval label makes reference to such a manual.

(b) No person may use a recreational vessel 16 feet or more in length unless one throwable PFD is onboard in addition to the total number of wearable PFDs required in paragraph (a) of this section.

(c) No person may operate a recreational vessel under way with any child under 13 years old aboard unless each such child is either—

(1) Wearing an appropriate PFD approved by the Coast Guard; or

(2) Below decks or in an enclosed cabin.