33 CFR §175.17

1. (a)Canoes and kayaks 16 feet or more in length are exempted from the requirements for carriage of the additional throwable PFD required under § 175.15(b).
2. (b)Racing shells, rowing sculls, racing canoes, and racing kayaks are exempted from the requirements for carriage of any PFD required under § 175.15.
3. (c)Sailboards are exempted from the requirements for carriage of any PFD required under § 175.15.
4. (d)Vessels of the United States used by foreign competitors while practicing for or racing in competition are exempted from the carriage of any PFD required under § 175.15, provided the vessel carries one of the sponsoring foreign country's acceptable flotation devices for each foreign competitor onboard.