Application The Fifth Order lens was used in leading lights, showing the line of a channel, or the entrance to a harbor. It was also used in river navigational lights to mark small shoals and islands in sounds, and to mark breakwaters. Three of the Great Lakes lights fitted with this lens were South Haven, Michigan City and Grand Traverse. Specifications |
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| Lens height: | 21.3". | |
| Focal length: | 7.4" | |
| Weight of assembly: | 265 to 440 lbs. | |
| Relative brightness (over sixth order): | 1.23 | |
| Useful range: | Up to 10 nautical miles. | |
| Number in US Lighthouses in 1884: | 131 | |
| Number in US Lighthouses in 1922: | 129 | |
| Oil consumption per hour: | 3.15 oz. | |
References Annual Report of the Lighthouse Board, 1884 The United States Lighthouse Service, Dept of Commerce, 1915 Aids to Navigation Manual, US Coast Guard, 1945 Comparative Table of Lens Orders, Mabel A. Baiges, 1988 Letter from Helen & Al Gademsky, 07/02/01 |
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