RS and RKO rules: practical application
Navigation power: switchboard, emergency operation and UPS
When ordering a radar, distinguish three questions from the outset: its normal power source, what happens on loss of the main supply and how operation is maintained during source transfer. A single statement that 'power is provided' does not describe the complete installation.
If discussed Koden MDC-7912P from RadarStation, the enquiry should describe the existing power system as well as display and antenna locations. Unit voltages and consumption must come from documentation for the exact version offered; this article does not infer them from the general series name.
What requirements are considered
This guide is based on section 2.2 of Part V, Navigation Equipment, of the RS Rules for the Equipment of Sea-Going Ships, version 01.01.2026. Under clause 1.1.1, this Part applies to self-propelled ships not engaged on international voyages and the relevant navigation equipment. Applicability to the project, including additional flag-administration instructions, must be checked separately.
Common shield and separate lines
Clauses 2.2.1–2.2.2 link navigation-equipment operation at sea to an adequate electrical supply and separate feeders from a common navigation switchboard. The text provides an exception for a heading- or track-control system; its supply is addressed through the separate reference in clause 2.2.5.
Clauses 2.2.6–2.2.7 provide for circuit breakers on outgoing circuits and prohibit unrelated consumers on the navigation switchboard. An upgrade enquiry should therefore include the existing diagram and connected-equipment list. Spare panel space alone does not establish whether a new connection is permissible.
This is a design and agreed-work-scope matter, not advice to redistribute loads yourself. Identify retained elements and the required outcome for the quotation; applicable arrangements must be established from installation documentation.
Mandatory conditions and recommendations
Clause 2.2.3 refers emergency-supply conditions to Part XI, Electrical Equipment, of the Rules for the Classification and Construction of Sea-Going Ships. In the same provision, use of a UPS is expressed as a recommendation. It must not automatically be rewritten as a requirement to install any separate device labelled UPS.
For a UPS-based supply, however, the clause describes alarms at the ship-control position: visual and audible warning of transfer to that source, automatic return after restoration of the ship supply and manual acknowledgement of the audible alarm. A power-unit name does not establish that these functions are included in the quotation.
This guide establishes neither emergency-supply duration nor calculated battery capacity. Those conclusions require assessment of the relevant provisions of Part XI for the vessel and the complete connected load.
What to include in the application
| Background information | What is required in the quotation |
|---|---|
| Models and composition of navigation equipment | A clear list of the units to be powered |
| Available navigation board diagram | The boundary between the retained installation and new supply |
| Envisioned sources and regimes | An agreed transfer-and-restoration sequence |
| Existing UPS, if available | Required accessories and unresolved compatibility questions |
| Alarms at the ship-control position | Device composition and agreed output |
The table is an editorial enquiry checklist. If some equipment will be retained, attach unit markings and documentation. Do not select a power supply solely by a similar connector or transfer specifications from an old version to a new one.
Position data for GMDSS: a separate issue
Clause 2.2.4 concerns radio-navigation receivers that automatically provide position and time to GMDSS radio installations: their supply is to be connected to the radio installation's reserve source. A navigation-system change may therefore also affect data supplied to radio equipment.
If such a circuit exists, show it in the project information even when the main order concerns the radar. This identifies connections to be retained. The radar itself must not automatically be treated as the required position source for all GMDSS equipment.
Sources
Checked on 25.10.2026, Astana time: the official RS catalogue, version 01.01.2026, bulletin No. 25-251297; Part V, ND No. 2-020101-1711.1.1, 1.1.3, 2.2.1 to 2.2.7.
The applicability of documents, completeness, availability, cost and timing are confirmed for a specific quotation. The illustration shows the theme of the technical guide, not the circuit of electrical connections.