Thanks for the ideas and links. Since the original one uses a higher-amp halogen bulb, and and LED would be more in line with the times.... I wonder if there is something like this sort of mounting available on the market. I note that Aquasignal does have a current version, but it's on a flex stalk which is nowhere near as handy for our chart table.
That said, situations requiring moving a light around to look at various parts of a paper chart at night are not as common as they used to be. We have the color plotter out at the helm and usually have the laptop computer open (and fastened down) on the chart table.
Now I wonder how many conductors are in that little cable? Next week I shall have a look-see.