Sec. 80.965  Reserve power supply.

    (a) Each passenger vessel of more than 100 gross tons and each cargo 
vessel of more than 300 gross tons must be provided with a reserve power 
supply independent of the vessel's normal electrical system and capable 
of energizing the radiotelephone installation and illuminating the 
operating controls at the principal operating position for at least 2 
continuous hours under normal operating conditions. When meeting this 2 
hour requirement, such reserve power supply must be located on the 
bridge level or at least one deck above the vessel's main deck.
    (b) Instead of the independent power supply specified in paragraph 
(a) of this section, the vessel may be provided with an auxiliary 
radiotelephone installation having a power source independent of the 
vessel's normal electrical system. Any such installation must comply 
with Secs. 80.955, 80.956, 80.957, 80.959, 80.961, 80.969 and 80.971, as 
well as the general technical standards contained in this part. 
Additionally, the power supply for any such auxiliary radiotelephone 
must be a ``reserve power supply'' for the purposes of paragraphs (c), 
(d) and (e) of this section.
    (c) Means must be provided for adequately charging any batteries 
used as a reserve power supply for the required radiotelephone 
installation. A device must be provided which, during charging of the 
batteries, gives a continuous indication of charging.
    (d) The reserve power supply must be available within one minute.
    (e) The station licensee, when directed by the Commission, must 
prove by demonstration as prescribed in paragraphs (e)(1), (2), (3) and 
(4) of this section that the reserve power supply is capable of meeting 
the requirements

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of paragraph (a) of this section as follows:
    (1) When the reserve power supply includes a battery, proof of the 
ability of the battery to operate continuously for the required time 
must be established by a discharge test over the required time, when 
supplying power at the voltage required for normal operation to an 
electric load as prescribed by paragraph (e)(3) of this section.
    (2) When the reserve power supply includes an engine driven 
generator, proof of the adequacy of the engine fuel supply to operate 
the unit continuously for the required time may be established by using 
as a basis the fuel consumption during a continuous period of one hour 
when supplying power, at the voltage required for normal operation, to 
an electrical load as prescribed by paragraph (e)(3) of this section.
    (3) For the purposes of determining the electrical load to be 
supplied, the following formula must be used:
    (i) One-half of the current of the radiotelephone while transmitting 
at its rated output, plus one-half the current while not transmitting; 
plus
    (ii) Current of the required receiver; plus
    (iii) Current of the source of illumination provided for the 
operating controls prescribed by Sec. 80.969; plus
    (iv) The sum of the currents of all other loads to which the reserve 
power supply may provide power in time of emergency or distress.
    (4) At the conclusion of the test specified in paragraphs (e) (1) 
and (2) of this section, no part of the reserve power supply must have 
excessive temperature rise, nor must the specific gravity or voltage of 
any battery be below the 90 percent discharge point.