| (1) | There must be available at all times while a ship to which this Part applies is at sea a main source of energy sufficient to operate the radio installations required by this Part and to charge any batteries used as part of a reserve source or sources of energy for those radio installations. |
| (2) | A reserve source or sources of energy must be provided on every ship to which this Part applies, to supply radio installations, for the purpose of conducting distress and safety radio communications, in the event of failure of the ship's main and emergency sources of electrical power. |
| (3) | Subject to subregulations (4) to (12), the reserve source or sources of energy must be capable of simultaneously operating the VHF radio installation required by regulation 10(1)(a) and, as appropriate for the sea area or sea areas for which the ship is equipped, either— |
| (a) | the MF radio installation required by regulation 12(1)(a); |
| (b) | the MF/HF radio installation required by paragraph (a) of ALTERNATIVE B in regulation 13(1) or by regulation 14; or |
| (c) | the INMARSAT ship earth station required by paragraph (a) of ALTERNATIVE A in regulation 13(1), |
and the additional loads mentioned in subregulations (7), (8) and (12), for the minimum period specified in subregulation (4).
| (4) | For the purposes of subregulation (3), the minimum period is— |
| (a) | in the case of ships constructed on or after 1 February 1995, one hour; |
| (b) | in the case of ships constructed before 1 February 1995— |
| (i) | one hour, if the emergency source of electrical power complies with the relevant provisions of regulation II-1/42 or 43 of the Safety Convention, including the supply of such energy to the radio installations; or |
| (ii) | six hours, if the emergency source of electrical power does not so comply, or no emergency source of electrical power is provided. |
| (5) | The reserve source or sources of energy need not be capable of supplying independent HF and MF radio installations simultaneously. |
| (6) | The reserve source or sources of energy must be independent of the ship's propelling power and main electrical system. |
| (7) | Where, in addition to the VHF radio installation, two or more of the other radio installations referred to in subregulation (2) can be connected to the reserve source or sources of energy, such source or sources must be capable of simultaneously supplying, for the minimum period specified, as appropriate, in subregulation (4)(a) or (b), the VHF radio installation and either— |
| (a) | all other radio installations that can be connected to the reserve source or sources of energy at the same time; or |
| (b) | if only one of the other radio installations can be connected to the reserve source or sources of energy at the same time as the VHF radio installation, whichever of the other radio installations will consume the most power. |
| (8) | The reserve source or sources of energy may be used to supply the electrical lighting required by regulation 8(1)(d). |
| (9) | Where a reserve source of energy consists of one or more rechargeable accumulator batteries— |
| (a) | a means of automatically charging each battery must be provided, that is capable of recharging them to minimum capacity requirements within 10 hours; and |
| (b) | the capacity of each battery must be checked at intervals not exceeding 12 months when the ship is not at sea. |
| (10) | The siting and installation of a reserve source of energy consisting of one or more accumulator batteries must be such as to ensure— |
| (a) | the highest degree of service; |
| (b) | a reasonable lifetime; |
| (d) | that battery temperatures remain within the manufacturer's specifications, whether under charge or idle; and |
| (e) | that, when fully charged, the one or more batteries provide a reserve source of energy for at least the minimum period specified in subregulation (4), under all weather conditions. |
| (11) | For the purpose of calculating the required capacity of the reserve source of energy, the total current used in calculations is to be equal to the sum of the total current consumption of all the radio installations that simultaneously can be connected to the source of energy, calculated by adding— |
| (a) | the current consumption of the VHF receiver; |
| (b) | one fifth of the current consumption of the VHF transmitter; |
| (c) | the current consumption of an MF or MF/HF receiver and of the transmitter when it is in such a condition that operation of the "press to transmit" switch will make it ready for immediate transmission; |
| (d) | one third of the current that may be drawn by an MF or MF/HF transmitter for speech transmission on the frequency at which the current consumption of the transmitter is at a maximum; |
| (e) | the current consumption of an INMARSAT ship earth station when it is receiving transmissions; |
| (f) | one quarter of the current that may be drawn by an INMARSAT ship earth station when it is transmitting in the mode at which the current consumption is at a maximum; and |
| (g) | the total current consumption of all additional loads to which the reserve source may supply energy in times of distress or emergency. |
| (12) | If an uninterrupted input of information from the ship's navigational or other equipment to a radio installation required by this Part, including the navigation receiver referred to in regulation 20, is needed to ensure its proper performance, means must be provided to ensure the continuous input of such information in the event of failure of the ship's main or emergency source of electrical power. |
