Sec. 80.917  Reserve power supply.

    (a) A vessel of more than 100 gross tons the keel of which was laid 
after March 1, 1957, must have a reserve power supply located on the 
same deck as the main wheel house or at least one deck above the 
vessel's main deck, unless the main power supply is so situated.
    (b) The reserve power supply must be independent of the ship's 
propulsion and of any other electrical system, and be sufficient to 
simulataneously energize the radiotelephone transmitter at its required 
output power, and the receiver. The reserve power supply must be 
available for use at all times.
    (c) When the reserve power supply consists of batteries, they must 
be installed as high above the bilge as practicable, secured against 
shifting with motion of the vessel, and accessible with not less than 26 
cm (10 in.) head room.
    (d) The reserve power supply must be located as near the required 
transmitter and receiver as practicable.
    (e) All reserve power supply circuits must be protected from 
overloads.
    (f) Means must be provided for charging any storage batteries used 
as a reserve power supply for the required radiotelephone installation. 
There must be a device which will give continuous indication of the rate 
and polarity of the charging current during charging.
    (g) The cooling system of each internal combustion engine used as a 
part of the reserve power supply must be adequately treated to prevent 
freezing or overheating consistent with the season and route to be 
travelled by the particular vessel involved.
[ 51 FR 31213 , Sept. 2, 1986, as amended at  58 FR 44954 , Aug. 25, 1993]