Maritek Tidal Manual

MARITEK

TIDAL HEIGHT PROGRAMS

Instructions for use

1. INTRODUCTION 2. THE PSION ORGANISER II 3. SETTING UP 4. DETERMINING THE HEIGHT OF THE TIDE 5. HIGH AND LOW WATER 6. RANGE 7. NEAPS AND SPRINGS

Copyright Notice
Programs and documentation are copyright by Maritek Ltd 1988, 1989
Tidal data have been supplied by the Proudman Oceanographic Laboratory. Copyright reserved.

1. INTRODUCTION

The Maritek tidal height and coastal navigation programs have been designed to be particularly easy to use. You don't need to be a computer expert and you don't need to be skilled in the use of the keyboard. The Maritek programs are operated by using only a very few keys. The keys which you will use most often are the ON/CLEAR and the "arrow" keys on the top row, and the (EXE) key on the bottom row. It will only take you a matter of minutes to follow the simple instructions after which you will use the computer with confidence.

One note of caution however: it is good sense and good seamanship never to rely totally on any one source of information; but to minimise the chance of errors by using all means at your disposal to verify your situation, so the use of this computer is not intended to replace charts and almanacs.

MENU SET-UP: IMPORTANT NOTE

Depending on which version of the programs you are using you may require to insert the word MARINE to the PSION menu. If MARINE does not appear when you switch on, then following the instructions in Chapter 17 of the ORGANISER manual (page 16-2 of the model LZ operating manual) use the (MODE) key, and when prompted "INSERT ITEM:" type the word MARINE, which will then appear in the menu. On the model LZ you are also asked to name the file type: here you should select Opl.

2. THE PSION ORGANISER II COMPUTER

If you have not used the PSION ORGANISER II computer before you should first familiarise yourself with certain features by reading the following few pages of the PSION ORGANISER II Operating Manual:

	Model CM or XP Pages	Model LZ or LZ64 Pages
Where things are	3-5	iii
Getting started	7-10	2-1, 2-2
The time function	13-14	2-4 to 2-6
Switching off	15	2-6
Changing Datapaks	27	13-2
Customising the Menu	65-67	16-2

3. SETTING UP

Ensure that two datapaks are fitted to the PSION ORGANISER thus:

TIDAL DATA in slot B (the upper slot)
TIDAL PROCEDURES in slot C (the lower slot)

Switch on the computer by pressing the (ON) key. You will see the display below with MARINE as the first item on the menu. The cursor should be flashing over the letter "M" in MARINE (the arrow keys can be used to position the cursor).

MARINE FIND SAVE DIARY CALC PROG

Now press the (EXE) key to display the MARITEK logo, then press (EXE) again to display the marine programs menu.

COASTAL TIDE ASTRO CLUB

Press (EXE) once more to display the tidal program menu.

Preliminary Set Up

(a) Setting the home port.

You can store the name of your home port on the datapak, after which this port will be displayed first each time you use the tidal height program. Select HOME from the menu by placing the cursor under the letter "H" and pressing the (EXE) key. You will then see the name of the first port on the second line of the display. Use the up arrow key to scroll through the ports to choose your home port. Use the down arrow key to scroll back again if required. When your chosen port is displayed press the (EXE) key to store the name. This port will be displayed first each time you select the tidal height program.

<<<<< PORT >>>>> GREENOCK

(b) Setting the time zone

When you have reset the computer's internal clock to say BST from GMT you will still obtain the tidal height at local time provided you also set the time zone indicator thus:

From the coastal navigation program menu select TIME by placing the cursor under the letter T of TIME and pressing the (EXE) key.

You will see a prompt on the top line and the bottom line shows the current setting shown as a number of hours ahead of (+) or behind (-) GMT (Greenwich Mean Time). Use the up/down arrow keys to set the time zone to match the time at which you have set the PSION Organiser's internal clock. Now press (EXE) to store it. Remember to change it each time you reset the time on the internal clock to a different time zone.

Indicate Zone.. GMT +1

Your selected time is stored in the PSION Organiser's main memory and should be secure even when changing batteries provided the battery is changed in accordance with the instructions in the Organiser's manual. There is no danger of a misleading result, because if the time zone date has been lost you will see the message "set time zone", when you attempt to compute a tidal height.

4. DETERMINING THE HEIGHT OF THE TIDE

Before you start ensure that the computer clock is set to the current date and time and that you have indicated to the computer what time zone you are in.

Go to the menu in which HEIGHT is the first option. (Press (EXE) from MARINE then (EXE) from TIDE.

HEIGHT HOME TIME HW. LW RANGE NEAPS. SPRINGS

With the cursor flashing over the "H" in "HEIGHT" press the (EXE) key. You will see the first port on the list. This may be your home port if you have set it up using the HOME option. Use the up and down arrow keys to find any port that you want from the list. Hold the arrow keys down for high speed scrolling.

<<<<< PORT >>>>> SOUTHAMPTON

Press the (EXE) key once more and today's date will be displayed. Use the arrow keys to display another date if you wish. Simply press the up or down arrow keys to change the day, then use the right arrow key to move the cursor to the month, and change the month by using the up or down arrow keys.

DATE: 15 AUG TIME: 13:47

When you have selected the date that you want press the (EXE) key and the current time will be displayed. Here again you may use the arrow keys as before to set hours then minutes to any time of day that you wish. Press EXE and the computer will work out the height of the tide in metres above chart datum for that date and time. This computation is performed in a matter of a few seconds. As the value is computed rather than interpolated from tables the result may well differ slightly from the height seen in published tables. The difference is usually insignificant and well within the prudent margin of error which should be allowed for meteorological and other factors when sailing.

TIME: 13:47 HEIGHT: 4.78 /

The symbol "\" beside the height indicates that the tide is ebbing as compared to the height half an hour earlier. The Symbol "/" similarly indicates that the tide is on the flood (rising). By pressing the up arrow key a few more times you will see how the tidal height changes at half hour intervals throughout the rest of the day.

If you leave the computer showing the time and height then after five minutes the computer will switch itself off. If you press the (ON) key subsequently it will return to the same display again and you may proceed normally from that point. if you press the ON/CLEAR key you will be returned to the PORT display. You may choose another port at this point or, press ON/CLEAR again to return the menu.

5. HIGH AND LOW WATER

The times of high tide and low tide (to the nearest half hour) can be determined. Select HW or LW from the menu. Then you will be shown your first (or home) port. Find any other port that you want by scrolling as before. Press (EXE) again and change the date if you wish. Press (EXE) and the time and height of high water or low water will be displayed.

H.W.: 7.00 Height: 5.81

6. RANGE

Select RANGE from the menu, when you will be shown the home port. Find any other port that you wish by scrolling as before. Press (EXE) and you will be shown today's date which you may alter. Press (EXE) and the ranges (in metres) will be computed and displayed for that day.

Range1: 5.22 Range2: 4.73

7. NEAPS AND SPRINGS

This option will display the dates of neap (or spring) tides in the present year (the dates of highest and lowest tides).