The Elfmill Tide Clock is a specially designed clock that tracks of the Moon's apparent motion around the Earth. In common with many tide clocks it keeps an approximation of the average time between high lunar tides: 12 hours 25 minutes and 14 minutes per revolution.
Again in common with most lunar tide clocks the Elfmill Tide Clock will gain up to 15 minutes or more per month and should be be reset periodically. The bottom of the tide clock dial is marked low tide and the top of the tide clock dial is marked high tide The left side of the dial is marked hours until high tide and has a count-down of hours from 5 to 1. There is one hand on the clock face and along the left side it points to the number of hours until the lunar high tide. The right hand side of the clock is marked hours until low tide and has a count-down of hours from 5 to 1. The number pointed to by the hand gives the time until the lunar low tide. Lunar Tides have an inherent lead or lag, known as the lunitidal interval. This interval differs at every location, so the Elfmill Tide Clock should be set for the time when the local lunar high tide occurs.
The lunar tide and solar tide are synchronized ebb and flow at the same time near the full moon and the new moon. The two tides are unsynchronized near the first and last quarter moon. The best time to set the clock is at the new moon or the full moon, which is also when the clock can most reliably indicate the actual combined tide.
A simple tide clock like the Elfmill Tide Clock will always be least reliable near the quarter moon.
Because ordinary tidal clocks only track a part of the tidal effect, and because the relative size of the combined effects is different in different places, they are in general only partially accurate for tracking the tides.
Consequently, all navigators use tide tables either in a booklet or on a computer. Elfmill Tide Clock should not be relied upon in any shape or form it is simply used as a rough indicator ALWAYS check a tide table booklet or reputable authority when making any plans relating to tidal changes.
The default tidal location setting is purely whimsical as tracks the Ebb and Flow of the tides of Elvian Island, an Elfish paradise, recently under threat from Goblins. See Elvian Island app coming soon to Android.
Elfmill Tide Clock © Copyright 2012 Elfmill Limited.