Abstract: An improved nautical clock apparatus of this invention is comprised of a clock base, a tide state indicator attached to the base, and an electronic controller attached to the tide state indicator and to the base for operating the tide state indicator to continuously indicate a time between successive like tide states based on a set time interval therebetween of about 12 hours and 25.235 minutes adjusted such that the time is longer than about 12 hours and 25.235 minutes during at least one portion of each lunar month and shorter than about 12 hours and 25.235 minutes during at least one other portion of each lunar month.

Abstract: Improved nautical clock apparatus and methods are provided. The nautical clock apparatus is basically comprised of a clock base and a tide state indicator attached to the base. Means are attached to the tide state indicator and to the base for causing the indicator to indicate the tide state based on a time of about 12 hours and 25.235 minutes between high tides and a continuous correction to such time which lengthens and shortens such time on a cycle whereby it is longer during one or more portions of each lunar month and shorter during one or more other portions of each lunar month.

Abstract: Improved nautical clock apparatus and methods are provided. The nautical clock apparatus is basically comprised of a clock base and a tide state indicator attached to the base. Means are attached to the tide state indicator and to the base for causing the indicator to indicate the tide state based on a time of about 12 hours and 25.235 minutes between high tides and a continuous correction to such time which lengthens and shortens such time on a cycle whereby it is longer during one or more portions of each lunar month and shorter during one or more other portions of each lunar month.

Abstract: A moon clock for indicating a phase of the moon. The moon clock comprises a moon disk rotatable about a central axis having moon representation means and a continuous scale disposed on the front surface thereof, drive means for rotating the moon disk at a rate corresponding to the rate of the lunar orbit, marker means for marking a position of the moon representation means that indicates a phase of the moon at a given time and for marking a division of the continuous scale, and a stationary vernier scale positioned adjacent to the continuous scale for measuring a fractional part of the division of the continuous scale marked by the marker means. Also provided is a tide clock for indicating a state of the tide.

Abstract: A moon clock for indicating a phase of the moon. The moon clock comprises a moon disk rotatable about a central axis having moon representation means and a continuous scale disposed on the front surface thereof, drive means for rotating the moon disk at a rate corresponding to the rate of the lunar orbit, marker means for marking a position of the moon representation means that indicates a phase of the moon at a given time and for marking a division of the continuous scale, and a stationary vernier scale positioned adjacent to the continuous scale for measuring a fractional part of the division of the continuous scale marked by the marker means. Also provided is a tide clock for indicating a state of the tide.