The U.S. Coast Guard stipulates that all recreational boats have one properly sized Coast Guard-approved life jacket in good, serviceable condition for each soul on board, and that the jackets are readily accessible, if not already being worn.
If your boat proves short on life-jacket stowage space, consider installing an overhead bag such as the T-Bag from Kwik Tek or the T-Top Marine Storage Bag from C.E. Smith. These ventilated, zippered bags attach with straps and buckles to the underside of Bimini tops and T-tops. Access is convenient and quick.