A chronometer having a tide grid comprising a contour line indicating at least one complete tide cycle and a superposed reading grid comprising at least one read-off reference mark. One of the grids is driven in rotation at a constant angular speed about an axis. The grids are concentric about that axis and the read-off reference mark is radially disposed relative to that axis The contour line indicates tides on polar coordinates such that the distance of a point on the contour line from that axis indicates the height of the tide. The radial read-off reference mark intersects the contour line at a point which indicates the height of the tide for the time shown by the chronometer for a specific geographical location.
A timepiece is provided in the form of a body having a face which displays a sinusoidal path of multiples of twelve wavelengths within a circular periphery, and concentric rings on the face which intersect the path. An arm rotates about the center of the face a rate of one revolution per every twelve hours. A time-indicating pointer, mounted for guided longitudinal movement with respect to the arm, reciprocates with respect to the arm at one cycle per hour. The combined rotation of the arm and reciprocation of the pointer cause the pointer to follow the sinusoidal path, such that the pointer indicates hours by its circumferential position relative to the crests of the wavelengths and indicates minutes by its radial position relative to the concentric rings.
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.
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.
