46 CFR §180.210

1. (a)A vessel of more than 19.8 meters (65 feet) in length must carry at least one rescue boat unless the cognizant OCMI determines that:
   1. (1)The vessel is sufficiently maneuverable, arranged, and equipped to allow the crew to recover a helpless person from the water;
   2. (2)Recovery of a helpless person can be observed from the operating station; and
   3. (3)The vessel does not regularly engage in operations that restrict its maneuverability.
2. (b)A vessel of not more than 19.8 meters (65 feet) in length is not required to carry a rescue boat unless:
   1. (1)The vessel carries passengers on an open or partially enclosed deck; and
   2. (2)The cognizant OCMI determines that the vessel is designed, arranged, or involved in operations so that the vessel itself cannot serve as an adequate rescue craft.
3. (c)In general, a rescue boat must be a small, lightweight boat with built-in buoyancy and capable of being readily launched and easily maneuvered. In addition, it must be of adequate proportion to permit taking an unconscious person on board without capsizing.
4. (d)On a vessel of more than 19.8 meters (65 feet) in length operating on protected waters, a rescue boat approved under approval series 160.056 is acceptable in meeting the intent of this section. On a vessel of more than 19.8 meters operating on exposed or partially protected waters, a rescue boat approved under approval series 160.156 is acceptable in meeting the intent of this section. On a vessel of not more than 19.8 meters (65 feet) in length, a required rescue boat must be acceptable to the cognizant OCMI.