46 CFR §185.508

1. (a)The master of a vessel shall require passengers to don life jackets when possible hazardous conditions exist, including, but not limited to:
   1. (1)When transiting hazardous bars and inlets;
   2. (2)During severe weather;
   3. (3)In event of flooding, fire, or other events that may possibly call for evacuation; and
   4. (4)When the vessel is being towed, except a non-self-propelled vessel under normal operating conditions.
2. (b)The master or crew shall assist each passenger in obtaining a life jacket and donning it, as necessary.