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1. Finding Height Of Tide At Time Between High And Low Water

The table is based on assumption of a simple harmonic type for the tidal curve.

This table will not be reliable for the places where the tide is diurnal or the

shallow water effect is considerable.

Finding the height of the tide at specified interval before and after the time of low

water, by adding a correction to its predicted height at low water.

Can be used for finding the height of the tide at a specified interval before or after

the time of high water, by subtracting a correction from its predicted height at

high water.

2. Conversion Table From Metres To Feet

3. The Depths on River Bars In Sarawak

The tide predictions include the effects of normal variations in mean level.

The depth of the bar below chart datum is almost impossible to predict and to give

general warnings of such changes in time.

4. The Lists of Standard Port

Hourly Height Prediction Daily Prediction

Pulau Lakei

Kuala Mukah

Pelabuhan Bintulu

Miri

Kuala Baram

Victoria Harbor, Labuan

Kuala Lundu

Kuala Santubong

Pulau Lakei

Pending

Sri Aman

Kanowit

National Hydrographic Centre, Royal Malaysian Navy

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Muara Harbor, Brunei

Kota Kinabalu

Sibu

Leba An

Sarikei

Tangjung Manis

Kuala Paloh

Muara Kut

Kuala Igan

Kuala Mukah

Kuala Balingan

Kuala Tatau

Pelabuhan Bintulu

Miri

Kuala Baram

Kuala Limbang

Kuala Lawas

Victoria Harbor, Labuan

Muara Harbor, Brunei

Kota Kinabalu

Kadat

Sandakan

Lahad Datu

Semporna

Tawau

Figure 1: Location of The Standart Port

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5. Chart Datum At Standart Ports

Gives information about the height of each port from Beach Mark (BM).

6. Predictions Hourly Height High And Low Water

Example of predictions table

7. Extra Tides

Give information about the tides in Sri Aman, Sarawak from January to August

2007.

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8. Time Differences For High And Low Water

Give approximate times of high and low water at the Secondary Port.

The variation is relatively small mean time differences are given, under the

heading M.H.W and M.L.W.

The high water as H.H.W and low water as L.L.W.

9. Tidal Levels At Standart Ports

Shows the simplified formulae of tidal level used for semi-diurnal ports which are

Mean High Water Spring (MHWS), Mean High Water Neap (MHWN), Mean

Low Water Spring (MLWN), and Mean Low Water Spring (MLWS).

Shows the simplified formulae of tidal used for diurnal ports which are Mean

Higher High Water (MHHW), Mean Lower High Water (MLHW), Mean Higher

Low Water (MHLW), and Mean Lower Low Water (MLLW).

10. Instruction for Use of Tables At Standart Ports

Give the explanation for the prediction of times of high or low water at Secondary

Ports.

Average levels at Springs or Neaps or at Higher High Water.

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1. Introduction

The tide table is made annually.

Tidal predictions are prepared for 22 tide stations using 60 tidal constituents.

The datum level that has been used for tidal predictions is the Indian Spring Low

Water (ISLW).

Provided the information on each Tide Station which are :

- Harmonic Constant

Department of Survey and Mapping Malaysia

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- Table of Hourly Height

- Table of Times and Height of High and Low Water

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- Tidal Marigram

2. The Explanation About The Content of Tide Tables

The Malaysian Standard Time used for prediction is 8 hours east of Greenwich.

All heights are in centimeters (cm) above Datum Level.

The explanation about the meaning of Sping Rise, Neap Rise, Spring Range,

Tropic Rise, Equatorial Rise, Tropic Range and Mean High Water Interval.

3. The Tide Stations

Give the position of tide station in Latitude and Longitude.

Datum Level.

Type of Tide.

Standard deviation of predicted time and predicted height.

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Figure 2: Location of Tide Station

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1. Table Conversion from Metres to Feet.

2. Introduction

Published by Sarawak Marine Department.

Datum for all predictions is Chart Datum

Accuracy of Prediction

- Used the tidal constituents.

- Basically the observations should be 18.6 years or more.

- The user of these tables should use more caution with the predictions based less than

one years observation.

Mean Level

- Observed levels at coastal ports can vary by 0.2 metres from the predicted values for

a month or more.

3. Predicted Ports

Sarawak Sabah

Sematan

Pasar Luncu

Kuala Santubong

Pending

Muara Tebas

Pulau Lakei

Sri Aman

Kuala Rajang

Tanjung Manis

Sarikei

Bintangor

Kota Kinabalu

Kudat

Sandakan

Lahad Datu

Tawau

Marine Department, Sarawak

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Figure 3: The Standart Ports

4. Chart and Tidal Datums at Predicted Ports.

Gives information about the height of each port from Beach Mark (BM).

Leba AN (Tanjung Ensurai)

Sibu

Kanowit

Kuala Paloh

Kuala Igan

Kuala Mukah

Kuala Balingian

Kuala Tatau

Kuala Kemena

Bintulu Port

Miri

Kuala Baram

Miri Port

Kuala Limbang

Kuala Lawas

Labuan

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5. Tidal Levels at Standard Ports.

Shows the height of water for Lowest Astronomical Tide (LAT), Mean Lower

Water (MLM), Mean Higher Low Water (MHLW), Mean Sea Level (MSL),

Mean Lower Height Water (MLHW), Mean Higher Height Water (MHHW), and

Highest Astronomical Tide (HAT) for each port.

Also show the period and year for observation.

6. Predictions by Ports.

Give the information for tide station which are:

Position of the station: Latitude and Longitude.

Height in Metres.

Hourly Heights Prediction

- This tide table shows the level of the tides for every hour in one day and every

month in that year.

- From that, it shows the movement of the tide.

Times and Heights of High and Low Water.

- Only show the time and height of high and low water for every tidal station

during that year.

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7. Tidal Level at Standard and Secondary Ports.

Example of tidal level

8. Hydrography Note and Hydrography Note for Port Information.

9. Speed-Time- Distance Table

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1. Introduction

These tables provide daily predictions of the times and heights of tide at major

ports, naval bases and fishing harbor within Sultanate of Oman.

Predictions are derived using up to 64 tidal constituents.

All heights are shown in meters (m) and decimeters (dm) above local Chart

Datum.

Times are referred to local time is GMT +4 hours.

Chart Datum at each site is fixed.

Distance Table in Nautical Mile.

2. The description of tides

Nature of the tide in Sultanate Oman

- The nature of the tide in Oman is best treated as being diurnal in nature.

- Predictions are derived from up to 64 harmonic constants.

Tidal range and shallow water effects

- The predicted ranges from Lowest to Highest Astronomical Tide vary from 2

meters in the south and 3.5 meters in the north.

Seasonal changes in Mean Sea Level

Meteorological effects on Tidal Levels

Tidal Datum and Reference Benchmarks

- Vertical datum for all tides is Chart Datum (Lowest Astronomical Tide)

- Chart Datum has been established at over 40 sites along Omans Coast.

Permanent Tidal Station and the National Hydrographic Datum (Wudam)

Royal Navy Oman

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Classification of Standard, Secondary and Minor Tidal Station

Standard Stations Secondary Stations Minor Stations

Port of Salalah

Masirah

Qalhat LNG

Terminal

Port Sultan

Qaboos

SBSNB Wudam

Port Sohar

Port Khasab

Dhalkut

Marbat

Al Hallaniyah

Lakbi

Ras Madrakah

Ad Duqm

Al Ashkharah

Sur

Qurrayat

Bandar al Khayran

Sidab

Khawr Muscat

Mina al Fahl

Shinas

Daba al Bayah

Lima

Khawr al Quway

Bukha

Ash Shuwaymiyah

Sarab

Mahawt

Rounders Bay

Khawr al Hajar

Barr AL Mukalla

Ras ash Shajar

Bimmah

Dibab

Daghmar

Bandar Jissah

Marsa al Murjan

Bait al Barakah

As Suwadi

Al Khaburah

Saham

Ras Dillah

Khawr Habalayn

Didamar

Khawr ash Shamm

Secondary ports

- Hourly height only

- Minor station : to apply Mean Higher High Water (MHHW), Mean Lower

High Water (MLHW), Mean Higher Low Water (MHLW) and Mean Lower

Low Water (MLLW).

New and Full Moon

Prediction of Tides between existing Tidal Station

3. The description of Tidal Streams and Currrents

Tidal flow is generally less than 1 knot.

Tidal streams are more dominant.

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4. Mean Ranges and Height and Time Differences

The information for every Reference Ports.

All heights in meters.

5. Principal Tidal Constituents

Harmonic constants can be used in tidal prediction.

Seasonal correction to Mean Sea Level is listed for the Standart Ports, secondary

and minor ports.

6. List of Radio Signals

Give all the information about the coast radio station and their services.

Radio aid to navigation.

Global maritime distress and safety system (GMDSS).

Vessel traffic services port operation and pilot station.

7. List of Light

The information on each light

8. National List of Wreck

Historic and protected wreck.

Information on each wreck.

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Figure 4: The Location of Oman Ports.

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Tide tables are used for tidal prediction and show the daily times and heights of high water and low water that usually for a particular location that is the uniform tidal system (semi

and diurnal). In a mixed system, it refers to higher high and lower high water and higher low and

lower low waters.

Tidal observations made over a period of time are used to calculate the average or mean

tide levels. Besides, the depth of coastal waters is important for navigation, therefore, an average

low-water reference is established. Water depths are measured from this level and recorded on

navigational charts. The low water reference point is usually established at the mean low-water

level, and a zero reference or tidal datum is established at this point. In mixed tidal areas, mean

low water is used as the tidal datum. Sometimes, the low-tide level may fall below the mean

value used as the tidal datum, producing a minus tide.

First and foremost, the need of the information shown in the Tide Tables is very

important for the navigation and hydrographic survey (Chart Datum). Navigating ships safely

through shallow water ports, intracoastal waterways, and estuaries requires knowledge of the

time and height of the tides as well as the speed and direction of the tidal currents. Besides,

Mariners need accurate data because the depths and widths of the channels along with increased

marine traffic leave very little room for error.

Last but not least, the Engineers also need data to monitor fluctuating tide levels for

harbor engineering projects such as the construction of bridges and docks. Projects involving the

construction, demolition, or movement of large structures must be scheduled far in advance if an

area experiences wide fluctuations in water levels during its tidal cycle. Habitat restoration

projects also require accurate knowledge of tide and current conditions. In addition, the

information of the tide tables such as tidal data and tidal currents are used for the fisherman in

order to help them improve their catches.

Discussion