Sec.  80.861   Required capacity.

   If the main power supply or the reserve power supply provided for the
   purpose of complying with  Sec.  Sec. 80.859 and 80.860 consists of batteries, the
   batteries must have sufficient reserve capacity available at all times while
   the vessel is leaving or attempting to leave a harbor or port for a voyage
   in the open sea, and while being navigated in the open sea outside of a
   harbor or port, to permit operation of the radiotelephone transmitter and
   the required receivers for at least 6 hours continuously under normal
   working conditions.