THE TIDE DISC (A) AND HOW TO READ IT
The light blue opposing scales on this disc indicate the current stages of the tide. L means low water, the first index 1/4 tide, the second 1/ 2 tide, the third 3 / 4 tide and H high tide. These scales are read as they pass over the light blue horizon ellipse on Disc B. The latter carries two sets of numerals, 6 to 1 before HIGH (high tide) and 1 to 6, afterwards. These enable you to read how many hours till high tide and how many hours have gone by since high tide.
Low tide occurs when the letter Lon the tide scales meets the words of LOW on the horizon ellipse. Depending on local conditions, low tides may not be equally spaced in time between successive high tides. Set for high tides if these are of major interest.
From your local newspaper, find the standard time of the next high tide at the location of your interest. Set one of the light blue tide scales at the correct number of hours and minutes before the next high tide. These figures appear on the light blue horizon ellipse, Disc (B). If the time on your clock dial is 1:00 p.m., and the next high tide occurs at 4 p.m. (in 3 hours) set the tide scale on the right hand, blue "3". See magnified view in illustration below.
More pictures of Spilhaus Space Clock and how to repair it.