Ebbs and flows. Low tides and tides in Bali. How to read the tide chart Solombala water gauge ebb and flow

As you remember from the school geography course, due to the rotation of the Earth and the gravitational forces of the Moon and the Sun, the level of the world's oceans in different parts of the planet fluctuates throughout the day, causing tidal phenomena on the coasts of large bodies of water (which, of course, includes the South China Sea). sea ​​with the Gulf of Thailand, where our favorite island is located).

Some particularly pedantic (read - experienced) tourists, when planning their vacation on the sea coast, be sure to take into account the time of high and low tides in a particular area on the selected travel dates.

Tidal chart: why it's important
be aware of?

Because the frequency and difference in water level fluctuations on the beach affects your vacation no less than the weather. Just imagine: you woke up on a hot morning, outside the window it was +35 °C in the shade. Having pulled on your bathing suit and grabbed a towel, you run out of your bungalow, dreaming of quickly taking a dip and freshening up... and suddenly you discover that the sea has “crept” away from the shore and has become noticeably shallower. Such surprises will happen to you with enviable regularity if you do not know what time the tides begin in a particular area during your vacation. For Koh Chang, this is also very important when planning dive depths, predicting the direction and strength of sea currents at dive sites, and so on.

Where can you find this valuable information?

You can download the tide chart for Koh Chang for the whole year at once using this link from the official website of the Department of Hydrography of Thailand. Find the Laem Ngop mark on the far right of the map - after clicking on the name, a very detailed (and if you want to figure it out, quite understandable) “schedule” for the current year in .pdf format will open.

Or use the official UK Hydrographic Office website at this link. Here, the tide times are predicted a maximum of 7 days in advance: the information better reflects reality and the English service works more clearly for the average person. For example, we want to find out at what hours and how strong the tides will occur on Koh Chang in April - for example, today and in the next week. We follow the link, select the required number of days in the drop-down list and click on the Predict button - a simple and understandable graph opens to us, from which it immediately becomes clear that tidal differences in sea level will be quite significant, the lowest water level will be in the mornings.

Seasonality of tidal phenomena
on Koh Chang island

From a tourist's point of view, the ideal time to relax is when the tide is low at night and the tide is high during the day. This is exactly how the Gulf of Thailand behaves in the high season; the ebb and flow of the tides minimally change the sea level off the coast (that is, there is always enough water on the beaches from November to March for a good swim).

But from the end of spring to the beginning of autumn, the tidal phenomena on Koh Chang change places: during the day the sea can “run away”, and in order to go to a depth sufficient for swimming, you will have to tread an additional couple of tens of meters in shallow water. In addition, due to the monsoon season (steady winds from the sea), fluctuations in ocean levels and tropical rainfall, the water in the surf can be cloudy. But all this does not prevent guests and those permanently living on the island from swimming all year round.

Ebb and flow situation
on selected beaches

How much water rises and falls on a particular beach also depends on the bottom topography. If the descent into the water is gradual and gentle, as on most of the island’s beaches, then vacationers here in the low season have to adjust their daily swimming regime to the ebb and flow of the sea. The following can give you such surprises: Klong Prao, White Sand (except for the northern part, it’s normal there) and Kai Bae Beach: for example, in the bay of the Seaview Hotel during periods of “low water” it is very shallow, to go to a depth of at least knee-deep, you need the walk is about 50 meters, and on some days you can walk (coral slippers are a must!) through shallow water to the island of Koh Man Nai lying opposite. But this does not mean at all that Kai Bay during this period is not at all suitable for swimming: in the central part (at Mam Kai Bae Beach) everything is more or less safe in this regard. We also need to mention the picturesque rock near the Cliff Beach Hotel - here is generally the best swimming place on the entire Kai Be Beach.

There are no problems with swimming in the low season in the Siam beach resort area on Longley Beach and, as we mentioned above, at the northern tip of White Sand - it is always deep enough there so as not to worry about the ebb and flow of the tides.

Thus, if you have certain knowledge or are simply philosophical about an additional short walk in the shallow sea, then the ebb and flow of the tides will not be able to ruin your beach holiday on Koh Chang at any time of the year! See for yourself...

Transition planning and navigation in the intertidal zone involves two main tasks:

How to take into account the direction and speed of the tidal current?

How to determine the depth at a given point at a given time?

The almanac helps to cope with both of these tasks “ REEDS ", which contains tide tables and current atlases for different navigation areas. Let's try to figure out how the problem of determining depth is solved.

The annual almanac contains two types of pages of interest to us: tables of tide heights and hourly atlases of tidal currents for different areas. We will use tide tables and tide curves to calculate the time and height of the tide.

It may seem that solving the problem of determining the depth at the desired point at a selected point in time is only accessible to seriously savvy people. But I will try to show that, apart from being careful and following a clear algorithm when using tide tables, there is nothing complicated here. If only you had an almanac at hand and (at first) an example of solving a similar problem in front of your eyes.

It is impossible to provide tidal tables for all ports, harbors and water areas in almanacs. Otherwise you would end up with a ledger the size of.... In general, it would be a very, very multi-volume and cumbersome publication. Therefore, the tidal tables provide information for the current year according to the so-called. "primary ports". And for calculating the depths of “secondary ports” at different points in time, corrections are given. But first things first.

Taskfor primary ports:

As an example, let's look at a typical case. We have rented a yacht in St Malo in the north of France and want to know what time on the morning of Sunday April 24th we can leave the marina. Marina St Malo has a threshold of 2 m at the exit (Sill). During low tide, this threshold prevents water from leaving the marina and maintains guaranteed depths in the marina water area.

For safe passage over the threshold (as well as over any drying heights), we need to have a depth reserve of at least 1 m under the keel.

The draft of our 46-foot yacht is 1.90 m. That’s all the condition of the problem. It only remains to add that the underlined number 2 in the inscription Sill (2 m) gives the value of the drying height above the level of minimum depths (Chart Datum).

Yacht draft (Draft), 1.80

Safety Clearance, 1.00

Drying out height, threshold (Drying Heigt, Sill), 2.00

1.80+1.00+2.00= 4.80 m.

That. To exit the marina, the tide height at that moment must be 4.80 m.

Let us now turn to the almanac, to the tables of tide heights.

2. The next step is to find the port closest to the place of interest to us.

All almanacs are issued for individual navigation areas (areas) and provide data for large ports or for ports located in special tidal conditions (Primery Ports or Standard Ports).

For all other ports and harbors (Secondary Ports), the tide height is calculated by reference to one of the primary ports.

Finding St Malo. St Malo is the primary port.

For primary ports, the almanac table provides data on the occurrence of low water and high water (Low Water and High Water). They are tied to standard time for each day of the year. Please note: some dates are highlighted in blue or red. The dates of spring tides are marked in red, and the dates of quadrature tides are marked in blue.

It is necessary to pay attention to the times indicated in the tables.

UTC (Universal Time Coordinated) or UT is the basis of civil time - the modern version of Greenwich Mean Time.

3. Convert ship's time to standard time.

All tide tables are constructed using the standard time in which people live in the sailing area of ​​interest.

Time is summer and winter. The almanac gives winter time, and summer time must be obtained from the almanac values. To do this, there is a reminder in the upper left part of the header:

Time zone ____

subtract (or add) __ hours for UT

For (region name) Summer Time add (orsubtract) ___ hour in non-shaded areas

That is (for example):

Time zone - 0100,

1 hour is subtracted from World Time.

For French summer time, add 1 hour to the unshaded zone data.

Attention! In the almanac, data related to winter time is shaded (so as not to be accidentally confused).

It is customary to write time in tables and maps without separating hours from minutes with dots or dashes: 1030.

3. Determining the time of low and high water

To determine the time of low and high water (LW and HW), you need to add one hour to the table time value.

And then the corrected time with the corresponding data (LW and HW) in the table would look like this.

From the values ​​​​obtained in the table, it is clear that we can leave the marina at 12-18, when the depth of full water will be 9.8 m. But we calculated that to pass over the ill-fated threshold, it is enough for us that the tide height at the time of exit is 4.80 m. How can we determine this “right moment”?

4. Determining the time when the safe passage depth will be at the point we need

Let's look at the Tidal Curves.

This is a graph of changes in sea level height that is used to determine the height of the tide at present. Typically, two curves are indicated on the graph: red - for syzygy and blue - for quadrature.

We need to go out between the first low and first high water, that is, in the morning between 0644 (3.4 m) and 1218 (9.8 m).

On the lower axis of low water (L.W.Hts.m) we will put point A, corresponding to the first (morning) low water - 3.4 m.

On the upper axis of high water (Н.W.Hts.m) we will put point B, corresponding to the first (morning) high water - 9.8 m. We connect the points with a straight line. This line conventionally characterizes the rise in water level during high tide.

We are interested in the level of 4.80 m. We raise the perpendicular from the 4.80 mark to the intersection with straight line AB and find point C. From point C we draw a horizontal line to the intersection with the tidal curve.

Since our release date is close to the date of the quadrature tide (Tuesday, April 26), we can assume that the point of intersection of D with the blue quadrature curve will be close to the desired result.

Now, to determine the exact time of exit, you need to use the time axis located under the tidal curve.

In the center we see the time of high water (HW), it is determined from the table - 1218.

On the left, 6 hours ago is the time of the first low water (LW), on the right, 6 hours ahead is the time of the second low water for this day.

From point D of intersection with the tidal curve, we lower the perpendicular to the time axis and obtain the exact exit time when the tide level reaches the value we need.

It turned out that the tide will reach the desired level 3 hours 50 minutes before the time of full water, i.e. at 8 hours 28 minutes. From now on, we can calmly and safely leave the marina, having a depth reserve of at least 1 meter when crossing the threshold. For convenience, there are empty rectangles under the time axis where you can enter the values ​​of each moment in time before and after the onset of high water at 1218.

When preparing the article, materials from the textbook "Yachting School" were used.

and skipper's reference book, Andrey Ivanichkin

The topic of ebbs and flows in Thailand is of interest to many. And this is not surprising, because the position of the moon, which controls water resources on the planet, determines whether your vacation will be ruined. If you suddenly find yourself at low tide, the beach will be completely unsuitable for swimming. The entire bottom will be open almost a kilometer from the shore, with algae, sea cucumbers, and shells visible on it, from which sea reptiles pull out their tentacles. At high tides, on the contrary, there is too much water; it literally creeps up to the very edge of the beach, leaving no room for rest. At the same time, the sea behaves quite aggressively, the waves lash against the edge of the barriers. In general, we would like to find harmony between these two states of the sea depths. And many services are trying to do this, and we will use their help to find out when is the best time to swim in the south of Thailand.

Since I lived for two seasons in the southwestern part of Thailand, I will talk about these regions. Namely about the provinces of Krabi, Phuket and Phang Nga. At least it will be more objective and truthful than I would unknowingly flood about the other islands, right?

In order to somehow orient ourselves in the schedule of ebbs and flows, we will have to turn to those who are directly involved in this. Because, to be honest, all my observations of the beaches over two seasons did not really provide any information. I used to think that the ebb and flow of tides is something natural, repeating not just every year, but every month. The Moon does not seem to change its position relative to the Earth, which means there should not be any global changes in the behavior of the sea on a particular shore. But I was wrong. It turns out that the ebb and flow of the tides are difficult to predict, with a lot of mathematical calculations, like predicting the weather.

The calculation of tides is often carried out by services related to fishing. Their earnings depend on it. After all, the most successful bite occurs during high tides, when a wave brings a lot of fish and other marine inhabitants from the sea. I have prepared tables with the tide schedule for the 2013-2014 season. From October to March.

From these tables you can find out what day of a particular month at what time the high tide or low tide will occur. The ideal days for swimming are when the fluctuations between all waves are minimal, i.e. the figure in all four columns is approximately equal to one, only slightly departing from it. If fluctuations from 0.3 to 2.5 meters occur during the day, then the ebb and flow of the tides on these days is pronounced. As a rule, this happens on the days of the full moon, as well as several days before and after it. The calmest sea is on the waning moon and before the new moon.

Tide calendar

Let me remind you that the data presented below is only suitable for the provinces of Krabi, Phuket and Phang Nga. It is also worth noting that the numbers are only approximately accurate. Depending on the specific beach, the time difference will vary by 10-25 minutes.

October 2013

November 2013

December 2013

January 2014

February 2014

March 2014

To compile the tables, we used the excellent service prilivy.com. If you haven’t found a schedule for the period you need, or want to see the tides in another part of Thailand, then this site will help you. This is almost the only normal service of this kind, and with perfectly implemented functionality.

As we have already noticed, ebbs and flows in Bali are a regular thing and you need to be prepared for them, ebbs and flows exist in all seas, sometimes they are less noticeable or almost invisible, as in the Black, Baltic, Marmara or Red Seas, but in for the rest, the values ​​of the minimum and maximum levels differ by meters.

Exact tide schedules exist for each port. In Bali, this is primarily the port of Benoa. But it is important for you and me to know when swimming is possible and when it is problematic. Also, the values ​​of the minimum and maximum levels are not very important to us. On some days the minimum level is the same, on other days it is different and vice versa. As you understand, they depend on the location of the Earth in its orbit and the distance of the Moon. The maximum fluctuations in water level during high and low tides in Bali are about 2-2.5 meters. It is comfortable to swim at a water level of 1 meter and above.

The greatest deviations in sea level are observed during the new moon and full moon. And the smallest level changes occur on days in the middle of them.

For our tourists, we suggest that you carefully study the tide schedules, if this is very important for you, and correctly shape your stay on the island, combining with and trips. For example, on days when the maximum low tide falls at the most productive time, we offer excursions around the island, trips to Lovina, Java, Komodo, a boat trip or fishing. If you find it difficult to make a plan yourself, leave it to us.

Tide graphs are very simple, you just need to combine the date line and the time line and at the intersection there will be a sea level value in meters for a given hour of the desired day. The schedules are not round the clock, but are scheduled only for the daytime part of the day.

March 2019

The height of the tides is determined by a complex combination of factors related to the position of the Earth, Sun and Moon. Because the Moon revolves around the Earth, the Earth revolves around the Sun and also rotates on its axis. The distances between the three celestial bodies and their relative positions to each other are constantly changing.
Depending on this distance and position, tides may be higher or lower, and tidal currents may be stronger or weaker.

In Bali, high and low tides occur twice a day.
It should be remembered that the ebb and flow of the tides will be different every day and will shift in time by about one hour. If your plans are flexible enough, you can use the tide table to choose a more convenient time. This means that sometimes it is necessary to wait a few days to get the best walking and photo opportunities.

Tides are expressed by a large number, closer to 2.0. This number indicates how high the tide will be at that day and time.
Low tides are expressed as an average number, closer to 1.0.
The lowest water level is highlighted in green, and is expressed as the smallest number tending to zero.
Strong winds can change the water level indicated in the table by up to half a meter.
Enjoy walking during low tides. Low tides are the best time to see marine life near the reef.

Attention! Reverse current!

If, while in the water, you find yourself in a rip current that quickly takes you away from the shore, do not panic and swim parallel to the beach to get out of the dangerous place.