Sec. 80.861  Required capacity.

    If the main power supply or the reserve power supply provided for 
the purpose of complying with Secs. 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.