Sec. 80.875  VHF radiotelephone power supply.

    (a) There must be readily available for use under normal load 
conditions a power supply sufficient to simultaneously energize the VHF 
transmitter at its required antenna power, and the VHF receiver. Under 
this load condition the voltage of the source of energy at the power 
input terminals of the VHF radiotelephone installation must not deviate 
from its rated value by more than 10 percent on ships completed on or 
after March 1, 1957, nor by more than 15 percent on ships completed 
before that date.
    (b) When the power supply for the VHF radiotelephone installation 
consists of batteries, they must be installed in the upper part of the 
ship, secured against shifting with motion of the ship, capable of 
operating the installation for 6 hours, and accessible with not less 
than 26 cm (10 in.) head room.
    (c) Means must be provided for charging any rechargeable batteries 
used in the ship's VHF radiotelephone installation. There must be 
provided a device which, during charging of the batteries, will give a 
continuous indication of the charging current.
    (d) The VHF radiotelephone installation may be connected to the 
reserve power supply of a compulsorily fitted radiotelephone or 
radiotelegraph installation.
[ 51 FR 31213 , Sept. 2, 1986, as amended at  58 FR 44953 , Aug. 25, 1993]