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Montague Island Lighthouse Heritage Management Plan 2020
Navigational requirement for AMSA AtoN sNavigational requirement for AMSA AtoN site
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Navigational requirement for AMSA AtoN site
| 1 | Objective/rationale | An AtoN is required on Montague Island, 30 miles south of Batemans Bay, to warn of the island itself and that it lies 3.8 miles off of the coast.This AtoN also warns of the unmarked Aughinish Rock which lies one mile to thesouth.This AtoN is required as a navigation mark for vessels transiting north–south along the eastern Australian coast.Ocean Data Acquisition System (ODAS) at depths of 15 metres are shown 3.1miles north and 4.2 miles north east of the island. |
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| 2 | Required type(s) of AtoN | A fixed structure is required to act as a day mark.A distinctive light is required for use at night. |
| 3 | Priority/significance | An AtoN at this site is important for the navigation of commercial ships. |
| 4 | Required measure ofperformance | IALA Availability Target Category 2 (99 per cent). |
| 5 | Primary and secondary means (if any) of identification | The day mark must be conspicuous. The existing 21 m high grey granite tower at an elevation of 80 m meets this requirement.The light must comply with the requirements of rhythmic characters of light as per the IALA Navguide. The light must have distinct characteristics that are easy to recognise and identify. The present flashing white light every 15 seconds meets this requirement. |
| 6 | Visual range | During daytime, the AtoN structure should be visible from at least 5 nauticalmiles.At night, the white light must have a nominal range of at least 20 nautical miles. |
| 7 | Radar conspicuousness | As the island itself will provide a good radar echo, no additional radarenhancement is required for this site. |