WO2004053774A1

WO2004053774A1 - Tide reckoner

Info

Publication number: WO2004053774A1
Application number: PCT/AU2003/001645
Authority: WO
Inventors: Clive Lewin Bacon
Original assignee: Clive Lewin Bacon
Priority date: 2002-12-10
Filing date: 2003-12-10
Publication date: 2004-06-24
Also published as: AU2002953246A0

Abstract

According to one aspect of the present invention there is provided a device for predicting tidal behaviour on a selected day at a selected location, the device including: a reckoner which includes a plurality of moon phase zones for a selected period of a year, each zone providing an indication as to a day in the period upon which a high tide or a low tide falls at a selected reference time; the device further including a tuner portion which, when associated with the reckoner, enables an approximate determination of the time at which the high tide or low tide occurs on a day other than those indicated days of each zone. According to another aspect of the present invention there is provided a method of predicting tidal behaviour for a selected date and location, the method including the steps of: selecting a datum moon phase incident day upon which a high or low tide falls at a selected reference time; identifying the number of days between the datum moon phase incident day and the selected tide prediction day; tuning the reference time to a tide incident time by a function of the number of days from the datum moon phase to predict the high tide and low tide incident times on the selected tide prediction day.

Description

TIDE RECKONER

One particular application for this invention involves the forecasting of tides. It will be convenient to hereinafter refer to this particular application, though it is to be understood that this is not to be taken as a limitation of the scope of the invention.

The most common method for obtaining ocean and river tidal times and height information specific to a particular geographic region such as for example New South Wales, Australia, is via printed tidal charts or websites that utilise information provided by tidal measurement authorities. These publication methods require that tidal times and heights for every day of the year be presented on either a printed chart or electronic site and in the case of printed charts a separate chart must be obtained for each specific state, territory or other tidal location. The information provided on these charts and sites are predictions calculated in most cases 12 months or more prior to the charted tidal date, and calculated generally by interpolation and extrapolation from data gained from previous years' measurements, or numerical solutions to complex mathematical equations. The charts are generally double-sided and printed on both sides of a page, and must be printed in small font to provide a useful time span of data in a convenient easy-to-carry form.

The present invention seeks to alleviate one or more of the above-mentioned disadvantages.

According to one aspect of the present invention there is provided a device for predicting tidal behaviour on a selected day at a selected location, the device including: a reckoner which includes a plurality of datum moon phase zones for a selected period of a year, each zone providing an indication as to a day or date in the period upon which a high tide or a low tide falls at a selected reference time; the device further including a tuner portion which, when associated with the reckoner, enables an approximate determination of the time at which the high tide or low tide occurs on a day other than those indicated days of each zone. The reckoner in one preferred form includes a first element in the form of a card or backing plate of any suitable shape, upon which is printed moon phase zones, tuner portions, datum moon phases and the selected reference time for the high tide or low tide coincident with the selected moon phase.

Each datum moon phase zone indicates a day or date on which a selected moon phase occurs, that day and moon phase selected as being coincident with a day on which a high tide or low tide in the selected location falls at a selected reference time. In a preferred form, a new moon phase indicator is placed in the datum moon phase zone corresponding to a new moon.

The datum moon phase zones may be arranged in any suitable manner, and preferably grouped into two sections, a first section corresponding with phases coincident with high tides falling at the reference time, and a second section corresponding with phases coincident with low tides falling at the reference time. Preferred arrangements of the datum moon phase zones include the first and second sections arranged concentrically into circles, or into inner- and outer-perimeters of a square, rectangle or triangle.

The device may be used for predicting behaviour over any suitable time period, from one month to one year, to several years.

Preferably each datum moon phase zone is further grouped into a plurality of phase clusters. In one embodiment a phase cluster corresponds with a group of selected moon phases falling within a selected calendar month.

The tuner portion provides the amount by which the number of days is adjusted in order to predict the approximate tide incident time for a day other than the date on which the datum moon phase occurs. The amount may vary from location to location, and may range from about 10 to 80 mins. In one form, the amount is in the form of an arithmetic function, being: (45mins x (no. of days of selected day from datum moon phase day)).

The reckoner may be in the form of a device including first and second elements, pivotally connected for relative rotation, or removably fixed by a non-setting adhesive. The second portion may have one or more marks or apertures to, respectively, align with or reveal corresponding information on a first element.

In one embodiment the tuner portion may be mounted on the second rotatable element. In this form the second rotatable element includes a datum mark, and a plurality of index marks which align with timing marks on the first element. This allows a fast tuning and calculation from the nearest datum moon phase day, of the approximate tide incident time on a day other than the datum moon phase day, by a simple rotation of the second rotatable element.

Another preferred embodiment includes first, second and third elements. The first and second elements are generally as described above, while the third element provides a calibration element so that the selected moon phase, that nearest the selected tide prediction day, may be aligned with the timing marks on the first element to indicate the reference tide incident time. The third element may be pivotally connected to the first and second elements for relative rotation or removably fixed by a non-setting adhesive.

All three elements may be adhered and given relative movement by providing a thin film of water between the elements, and keeping air bubbles out of an interface therebetween. Air pressure, in this case, keeps the elements together, and still enabling some relative movement.

A location device may be provided in order to easily calibrate the prediction to the relevant longitude. Thus, for most people it is easier to remember that they are on the same longitude as the east coast of Hawaii than to say that they are on the same longitude as, say 155°W (which is approximately the longitude for the east coast of Hawaii). In one form the reckoner may be laminated and adhesive backing applied, so that the reckoner may be adhered to a surface such as a surfboard deck or fishing tackle box and calculated on-site, even though water maybe washing over the surface of the reckoner.

According to another aspect of the present invention there is provided a method of predicting tidal behaviour for a selected date and location, the method including the steps of: selecting a datum moon phase incident day upon which a high or low tide falls at a selected reference time; identifying the number of days between the datum moon phase incident day and the selected tide prediction day; tuning the reference time to a tide incident time by a function of the number of days from the datum moon phase to predict the high tide and low tide incident times on the selected tide prediction day.

In order to enable a clearer understanding of the invention, drawings illustrating example embodiments are attached, and in those drawings:

Figures 1 - 3 are separate example embodiments of device for predicting tidal behaviour, each showing only the example arrangements of phase zones and clusters, and without showing the tuning portions;

Figures 4 and 5 are further example embodiments of device according to the present invention, the device in the form of a first element, including: tuning portions; moon phase indicators; moon phase dates; and phase zones grouped into high- and low- tide sections. It is noted that Figure 1 is essentially the same embodiment as Figure 5, without numerals and tuning portions;

Figure 6 is a second element showing a tuning portion mounted on a second element;

Figure 7 is a further embodiment of device, being a first element for use with the second element in Figure 6; Figure 8 shows the arrangement in use of the first and second elements shown in Figures 6 and 7;

Figure 9 is yet another embodiment showing first, second and calibration elements.

Referring to Figures 1 and 5 the device is generally indicated at 10, including a reckoner 12 mounted on a first element 13 in the form of a card 15 and typical datum moon phase zones, indicated at 14. The datum moon phase zones 14 are, for simplification only, arranged into concentric rings, outer 16, and inner 18. The New and Full datum moon phases are placed in an outer ring 16, signifying correspondence with high tides falling at a reference time, and First- and Last-Quarter moon phases are placed in an inner ring 18, signifying correspondence with low tides falling at a reference time.

The datum moon phase zones 14 are further grouped into phase clusters 20 which represent calendar months, for further simplification. The day of the week on which a phase occurs is also noted on the reckoner 12 next to its respective moon phase zone 14.

A new moon symbol 22 is provided for convenience, representing the falling of a new moon.

A qualitative tide range symbol is provided at 24, highlighting to users that tide heights change in relation to the local season, so they may prepare themselves accordingly.

A tuner portion 26 is provided on the reckoner 12, which allows the user to determine the local tidal time at a selected date, using both the time period from the nearest moon phase to the selected day, and a calibrated local tidal incidence at a moon phase.

To demonstrate use the device in predicting a particular tide incident, reference will be made to an example, and Figures 4 and 5:

If a user wanted to reckon a tide incident in a particular location for 6 January 2003, a date not specifically included on the reckoner 12, they first calibrate the device 10 to the selected area. This calibration is done by determining the reference time at which tides fall in relation to selected moon phases: the "tidal fingerprint". For the east coast of Australia, the tidal fingerprint is: a high tide at approximately 0800hrs on the occurrence of a new or full moon; and a low tide at approximately 0800hrs on the occurrence of a quarter moon.

The user must then identify the nearest moon phase date to 6 January 2003. This is done by turning to the January phase cluster, and noting that the nearest datum moon phase is 9 January 2003. Tidal behaviour in this instance will be reckoned from the low tide, as the inner ring 18 will be used, because the datum moon phase at 9 January 2003 is a low tide, on the inner ring.

The overriding rule in reckoning tides with this invention is that, for every day which progresses in time from a given moon phase date to the selected date, the user delays the reckoner 12 calibrated time by a selected amount (in this case) 45 minutes, and for every day earlier in time from a given moon phase date to the selected date the user deducts the reckoner 12 calibrated time by (in this case) 45 minutes. This information forms part of the tuning portion 26.

The number of days from 9 January to 6 January is three, backwards in time. Therefore we must accelerate 45 minutes per day (135minutes) from the calibrated low tide time at the quarter moon phase, which was 0800hrs. Thus, the low tide is reckoned as 0600hrs. The other tides for the day may be reckoned with the knowledge that the time between tides is approximately 6.5hrs. Thus, the next high tide after the example reckoned would be at 1230hrs.

It should be noted that the device 10 may have an error of ± 30minutes due to tidal dynamics at different locations.

Referring to Figures 6 - 8 there is shown another embodiment of reckoner having a first element 113 and a second element 135. The second element includes markings 138, 138B, etc which correspond with days.

In use, an index marking 137 on the second element 135 is aligned with the selected date of the nearest datum moon phase zone of interest. The number of days that a selected date is from the datum moon phase is then calculated, and to perform the tide estimation, the number of days required is stepped around the second element via the markings 138, 138b, etc to reach the accelerated or retarded time of tide incident.

A ring of time marks indicate at 131 is provided, to make it easier to calculate the predicted tide incident time.

Referring to Figure 9 there is shown yet another embodiment of reckoner having first 213, second 235 and calibration 240 elements pivotally connected together for relative rotation. In use the calibration element 240 is rotated to align the date of the nearest datum moon phase of interest to the reference time upon which the high- or low-tide falls (for east coast of Australia, approximately 8 o'clock EST). Then the tide is then estimated using the method described in relation to Figures 6 - 8.

The reckoner may be checked and calibrated by reference to web sites which provide tide data for a particular location, preferably for multiple locations on a particular line of longitude so that an average time may be used to calibrate the reckoner. Card charts and newspapers may also be used, but again, it is preferred to gain an indication of the tidal incident time along a line of longitude (card charts generally only give tide details for a single location). Measurements and observations may be made over a period of time at a location of interest to calibrate the reckoner.

An advantage of using the reckoner's clock face, particularly the circular face, divided into months of the year, is that the twelve moon phase clusters may be equated to the hourly divisions on the face of a clock, and may assist in the mental arithmetic required to calculate times. Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A device for predicting tidal behaviour on a selected day at a selected location, the device including: a reckoner which includes a plurality of moon phase zones for a selected period of a year, each zone providing an indication as to a day in the period upon which a high tide or a low tide falls at a selected reference time; the device further including a tuner portion which, when associated with the reckoner, enables an approximate detennination of the time at which the high tide or low tide occurs on a day other than those indicated days of each zone.

2. A device in accordance with claim 1 wherein the reckoner includes a first element in the form of a card or backing plate, upon which is printed the moon phase zones, the tuner portion and the selected reference time for the high tide or low tide coincident with the selected moon phase.

3. A device in accordance with claim 1 or 2 wherein a moon phase indicator is located in the moon phase zone corresponding to selected moon phases.

4. A device in accordance with any previous claim wherein the moon phase zones are grouped into two sections, a first section corresponding with phases coincident with high tides falling at the reference time, and a second section corresponding with phases coincident with low tides falling at the reference time.

5. A device in accordance with claim 4 wherein arrangements of the moon phase zones include the first and second sections arranged concentrically into circles, or into inner- and outer-perimeters of a square, rectangle or triangle.

6. A device in accordance with any previous claim wherein the device is used for predicting behaviour over a one year period by including moon phase zones corresponding to 12 months.

7. A device in accordance with any previous claim wherein each moon phase zone is further grouped into a plurality of phase clusters.

8. A device in accordance with claim 7 wherein each phase cluster corresponds with a group of selected moon phases falling within a selected calendar month.

9. A device in accordance with any previous claim wherein the tuner portion provides the amount by which the number of days is adjusted in order to predict the approximate tide incident time for a day other than that indicated in a selected moon phase zone.

10. A device in accordance with any previous claim wherein the tuner portion provides an arithmetic function, being:

(A mins x (no. of days of selected day from datum moon phase day));

in order to allow reckoning of the approximate tide on a day other than those indicated in the moon phase zones.

11. A device in accordance with claim 10 where A is between 10 and 80 minutes.

12. A device in accordance with claim 10 or 11 where A is 45 minutes.

13. A device in accordance with any previous claim wherein the reckoner includes a second element pivotally connected to the first element for relative rotation, or removably fixed to the first element by a non-setting adhesive.

14. A device in accordance with claim 13 wherein the second element has one or more marks or apertures to respectively align with, or reveal corresponding information on the first element.

15. A device in accordance with claim 13 or 14 wherein the tuner portion is mounted on the second element.

16. A device in accordance with any one of claims 13 - 15 wherein the second element includes a datum mark, and a plurality of index marks which align with timing marks on the first element, to allow a fast tuning and calculation from the nearest datum moon phase day, of the approximate tide incident time on a day other than the datum moon phase day, by a simple rotation of the second rotatable element.

17. A device in accordance with any previous claim wherein the reckoner includes a calibration element so that the selected datum moon phase day , that nearest the selected tide prediction day, may be aligned with the timing marks on the first element to indicate the reference tide incident time.

18. A device in accordance with claim 17 wherein the calibration element may be pivotally connected to the first and second elements for relative rotation or removably fixed by a non-setting adhesive.

19. A device in accordance with any one of claims 13 - 18 wherein the second and calibration elements are adhered and given relative movement in relation thereto when in use by providing a thin film of water between the elements, and substantially keeping air bubbles out of an interface therebetween, so as to keep the elements together by air pressure and still maintain a degree of relative movement.

20. A method of predicting tidal behaviour for a selected date and location, the method including the steps of: selecting a datum moon phase incident day upon which a high or low tide falls at a selected reference time; identifying the number of days between the datum moon phase incident day and the selected tide prediction day; tuning the reference time to a tide incident time by a function of the number of days from the datum moon phase to predict the high tide and low tide incident times on the selected tide prediction day.

21. A method according to claim 20 which includes the use of a device in accordance with any previous claim, to predict the high tide and low tide incident times on the selected day.

22. A device for predicting tidal behaviour substantially as hereinbefore described with reference to the drawings.

23. A method for predicting tidal behaviour substantially as hereinbefore described with reference to the drawings.