Tides revision lrg

Grunt Productions 2007

Tides and Tidal Tides and Tidal StreamsStreams

A Brief By Lance GrindleyA Brief By Lance Grindley


Reach

Hook

Calshot

Black Jack

Castle Point

Calshot Spit

North ThornBourne Gap

RFA

LCT

Merchant Ship 1051

1051

1053

1053

1055

1055

1057


Range of LessonRange of Lesson

• Calculating heights and depths from levels and datum's.

• Calculating predicted heights for any Standard Port (European and Non-European)

• Calculating predicted heights for European and Non-European Secondary Ports (including Solent)

• Calculating tidal streams using tidal diamonds and Tidal Stream Atlases


Tidal PredictionTidal Prediction

• Admiralty Tide Tables (4 volumes)

• Volume 1 UK and Channel Coast

• Volume 2 European and Atlantic Waters

• Volume 3 Indian Ocean

• Volume 4 Pacific Ocean


Heights and Datum'sHeights and Datum's

• All depths and drying heights are measured from the Chart Datum.

• Tidal datum's LAT, MLWS, MLWN, MSL, MHWN, MHWS and HAT are given as heights above Chart Datum.

• Chart Datum is usually set at LAT

• All heights are measured from MHWS


Tidal Tidal Heights Heights

and and Datum'sDatum's

DATUM FOR HEIGHTS

DATUM FOR DEPTHS


Tidal Datum'sTidal Datum's

MHWS

Chart Datum

MLWS

MHWN

MLWN

HAT

LAT

MSL


Charted HeightCharted Height

MHWS

Chart Datum


Minimum Clearance 2mMinimum Clearance 2m

DraughtMinimum Height of Tide

Charted Depth 2m minimum


Masthead ClearanceMasthead Clearance

Maximum Height of Tide

Charted Depth

MHWS

Charted HeightMasthead Clearance


ExampleExample

• Port of MILFORD HAVEN

• Power cable with charted height 24m

• Minimum charted depth 4m

• Vessel details: - masthead height 22m

• - draught 6m.

• Clearances: - masthead 3m

• - under keel 2m


DiagramDiagram

Bridge

Seabed

22m

6m Chart Datum4mHoT

MHWS7m

24m

3m

2m


Max/Min height of tideMax/Min height of tide

• Minimum HoT = 6m+2m-4m = 4 metres

• Maximum HoT = 24m+7m-(22m+3m)

• 31m - 25m = 6 metres

• Height of tide must lie between 4 and 6 metres


European PortsEuropean Ports


PublicationsPublications

• Admiralty Tide Tables Volume 1 (United Kingdom and Ireland) (Including European Channel Ports).

• Admiralty Tides Tables Volume 2 (Europe excluding United Kingdom and Ireland) Mediterranean Sea and Atlantic Ocean.

• Admiralty List of Radio Signals Volume 2 (Radio Time Signals).


Standard PortsStandard Ports

• List of ports inside front cover of ATT.• Predictions are given in the Standard

Time Zone for the country.• If necessary times must be adjusted for

Daylight Saving Time (DST) usually one hour ahead of standard time.

• First page of standard port predictions will be the tidal curve unique to that port.


Height of TideHeight of Tide

Time

Height of Tide

Chart Datum

HW

Predicted Height

LW

Range of Tide

Duration

Height of Tide

LW

Interval

Height of Tide


Express Range as PercentageExpress Range as Percentage• Difference between the Mean Neap Range and

the Mean Spring Range is 100%.• Any range can be expressed as a percentage

increase from the MNR.• Example (Portsmouth) MSR 3.9m MNR 1.9m• Difference of 2.0m represents 100% Springs• Range of 3.0m is 3.0-1.9/2.0 = 1.1/2.0 = 55%


ExampleExample

• Calculate the height of tide at 1100A on 5th June at PORTSMOUTH.

• Standard port predictions for Portsmouth from page 2A-49.


Portsmouth PredictionsPortsmouth PredictionsENGLAND - PORTSMOUTH

Lat 5048’N Long 107’WTIME ZONE UT (GMT) TIMES AND HEIGHTS OF HIGH AND LOW WATERS YEAR 1998

JUNE JULYTime m Time m Time m Time m0338 4.1 0301 4.3 0458 0.8 0435 0.91 0911 1.4 16 0838 1.1 1 1144 4.8 16 1119 4.61819 4.1 1543 4.4 1723 0.6 1657 0.7M2140 1.7

F2109 1.3

M TU 2347 4.7

0427 3.9 0356 4.2 0015 4.8 0515 0.82 1008 1.6 17 0937 1.3 2 0539 0.8 17 1200 4.61715 4.0 1641 4.3 1227 4.7 1738 0.6TU2244 1.8

SA2213 1.4

TU1803 0.6

W

0527 3.7 0459 4.1 0056 4.7 0027 4.73 1114 1.8 18 1044 1.3 3 0618 0.8 18 0555 0.61819 3.9 1747 4.3 1306 4.7 1242 4.7W2354 1.9

SU2324 1.5

W1840 0.7

TH1817 0.5

0638 3.7 0609 4.1 0133 4.7 0108 4.84 1221 1.8 19 1157 1.3 4 0654 0.9 19 0635 0.61924 4.0 1857 4.3 1343 4.5 1324 4.7TH M TH

1914 0.8F

1857 0.5

0058 1.8 0037 1.4 0208 4.6 0150 4.85 0748 3.8 20 0722 4.2 5 0728 1.1 20 0716 0.61320 1.7 1307 1.2 1419 4.4 1407 4.7F2019 4.1

SA2003 4.5

F1946 1.0

SA1939 0.6

0151 1.6 0144 1.2 0243 4.5 0233 4.76 0841 3.9 21 0830 4.3 6 0802 1.3 21 0800 0.81408 1.5 1409 1.1 1455 4.2 1452 4.5TU2105 4.2

SU2103 4.6

SA2019 1.2

SU2023 0.8


Tidal Prediction FormTidal Prediction Form

STANDARD PORT……………………TIME/HEIGHT REQUIRED…………

SECONDARY PORT…………………..DATE…..……….TIME ZONE……...

STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Portsmouth

5 June

1100

A

0746 3.8m1320 1.7m 2.1m

0846A

10% Sp


Tidal Curve - PortsmouthTidal Curve - Portsmouth

HW +1 +2 +3 +4 +5-1-2-3-4-5-6

0 2 43 51

0 21 3

MEAN RANGESSprings 3.9mNeaps 1.9m

PORTSMOUTH

0846A

HW 3.8m

LW 1.7m


Tidal Curve - PortsmouthTidal Curve - Portsmouth

HW +1 +2 +3 +4 +5-1-2-3-4-5-6

0 2 43 51

0 21 3


PORTSMOUTH

0846A

3.3m

1100A


Secondary PortsSecondary Ports

• Times and heights are obtained by applying time and height differences to Standard Port predictions.

• Obtain Port Number from Geographical Index at back of ATT.

• Use Part II (page 300-323) to obtain:• Standard Port• Secondary Port time Zone• Secondary Port differences.


ExampleExample

• Find out what time the height of tide will first rise to 5.0 metres at WATCHET (531) on 26th July,

• Page 2A-102 for Secondary Port Differences.


Secondary Port DifferencesSecondary Port Differences

WALES; ENGLAND, WEST COAST

No PLACE TIME DIFFERENCES HEIGHT DIFF (METRES)Lat Long High Water Low Water MHWS MHWN MLWN MLWS N W Zone UT (GMT)

0200 0800 0300 0800523 PORT OF BRISTOL and and and and 13.2 9.8 3.8 1.0(AVONMOUTH) …(see page 158) 1400 2000 1500 2000

531 Watchet 51 11 3 20 -0035 -0050 -0145 -0040 -1.9 -1.5 +0.1 +0.1





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Avonmouth 5.0m

Watchet 26 Jul A





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Avonmouth 5.0m

Watchet 26 Jul A

0858 12.8m0328 1.1m 11.7m

92% Sp


High Water DifferencesHigh Water Differences




531 Watchet 51 11 3 20 -0035 -0050 -0145 -0040 -1.9 -1.5 +0.1 +0.1

1400 - 0858 - 0800

-0035 -0050

-48 min


Interpolation of HW TimesInterpolation of HW Times

0800 0900 1000 1100 1200 1300 1400

Times of HW at Bristol

Watchet Differences

-50 min -35 min-48m --45m -43m -40m -38m


Low Water DifferencesLow Water Differences




531 Watchet 51 11 3 20 -0035 -0050 -0145 -0040 -1.9 -1.5 +0.1 +0.1

0300 - 0328 - 0800

-0145 -0040

-0138


Interpolation of LW TimesInterpolation of LW Times

0300 0400 0500 0600 0700 0800

Times of LW at Bristol

Watchet Differences

-105m -92m --79m -66m -53m -40m


High Water CorrectionHigh Water Correction




531 Watchet 51 11 3 20 -0035 -0050 -0145 -0040 -1.9 -1.5 +0.1 +0.1

12.8m

13.2m 9.8m

-1.9m -1.5m

-1.9m -1.8m -1.7m -1.6m -1.5m

13.2m 12.4m 11.5m 10.7m 9.8m


Low Water CorrectionLow Water Correction




531 Watchet 51 11 3 20 -0035 -0050 -0145 -0040 -1.9 -1.5 +0.1 +0.1

1.1m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Avonmouth 5.0m

Watchet 26 Jul A

0858 12.8m0328 1.1m 11.7m

-0048 -0138 -1.9m +0.1m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Avonmouth 5.0m

Watchet 26 Jul A

0858 12.8m0328 1.1m 11.7m

-0048 -0138 -1.9m +0.1m

0810Z 0150Z 10.9m 1.2m

0910A


Tidal Curve - AvonmouthTidal Curve - Avonmouth

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

0 4 862

0 42 6


AVONMOUTH10 12 14

0910A


Tidal Curve - AvonmouthTidal Curve - Avonmouth

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

0 4 862

0 42 6


AVONMOUTH10 12 14

0910A0550A


Seasonal ChangesSeasonal Changes

•Usually caused by meteorological trends or effect of river water on height of tide. •See notes on page 2B-7.•ATT Standard Port predictions always include expected seasonal changes so no correction is required.•When comparing the standard port predicted height with mean levels the effect of seasonal variations should be removed.



•Having removed the effect of seasonal change for the standard port, the effect of seasonal change must be included in the secondary port prediction.•Tidal prediction forms (box 6) should be used to remove standard port seasonal change (change sign) and include secondary port change (box 11) to calculate final heights.


ExampleExample

•A53. What is the height of tide at 0800A on 28

February at ILMUIDEN (1501)?

•Standard Port VLISSINGEN (Page 2A-74)

•HW 0253A 4.9m LW 0927A -0.1m

•Range 5.0m is 2.0m/1.5m = 133% Springs



STANDARD PORT……………………TIME/HEIGHT REQUIRED………….


STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Vlissingen

Ijmuiden 28 Feb -1

0800

0927(-1) 4.9m0253(-1) -0.1m 5.0m

133%Sp


Seasonal ChangesSeasonal Changes

NETHERLANDS

No PLACE TIME DIFFERENCES HEIGHT DIFF (METRES)Lat Long High Water Low Water MHWS MHWN MLWN MLWS N E Zone -0100

0300 0900 0400 10001523 VLISSINGEN(FLUSHING) and and and and 4.8 3.9 0.9 0.3

…(see page 198) 1500 2100 1600 2200

1501 Ijmuiden 52 28 4 35 +0145 +0140 +0305 +0325 -2.7 -2.2 -0.6 -0.1

SEASONAL CHANGES IN MEAN LEVEL

No Jan1 Feb1 Mar1 Apr1 May1 Jun1 Jul1 Aug1 Sep1 Oct1 Nov1 Dec1

1501-1521 0.0 0.0 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 +0.1 +0.1 +0.11528-1571 0.0 0.0 -0.1 -0.1 -0.1 -0.1 0.0 0.0 0.0 +0.1 +0.1 +0.11572 1581a 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 0.0 +0.1 +0.1 0.0 0.01582-1595a 0.0 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 0.0 +0.1 +0.1 +0.1





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Vlissingen

Ijmuiden 28 Feb -1

0800

0927(-1) 4.9m0253(-1) -0.1m 5.0m

133%Sp+0.1m +0.1m


Ijmuiden - HW DifferencesIjmuiden - HW Differences

NETHERLANDS



…(see page 158) 1500 2100 1600 2200

1501 Ijmuiden 52 28 4 35 +0145 +0140 +0305 +0325 -2.7 -2.2 -0.6 -0.1





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Vlissingen

Ijmuiden 28 Feb -1

0800

0927(-1) 4.9m0253(-1) -0.1m 5.0m

133%Sp+0.1m +0.1m

+0145m


Ijmuiden - LW DifferencesIjmuiden - LW Differences

NETHERLANDS



…(see page 158) 1500 2100 1600 2200

1501 Ijmuiden 52 28 4 35 +0145 +0140 +0305 +0325 -2.7 -2.2 -0.6 -0.1





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Vlissingen

Ijmuiden 28 Feb -1

0800

0927(-1) 4.9m0253(-1) -0.1m 5.0m

133%Sp+0.1m +0.1m

+0145m +0323m


Ijmuiden - Height of Tide Ijmuiden - Height of Tide DifferencesDifferences

NETHERLANDS



…(see page 158) 1500 2100 1600 2200

1501 Ijmuiden 52 28 4 35 +0145 +0140 +0305 +0325 -2.7 -2.2 -0.6 -0.1

4.8 4.6 4.4 4.2 4.0 3.9

-2.7m -2.6m -2.5m -2.4m -2.3m -2.2m

5.0

-2.8m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Vlissingen

Ijmuiden 28 Feb -1

0800

0927(-1) 4.9m0253(-1) -0.1m 5.0m

133%Sp+0.1m +0.1m

+0145m +0323m -2.8m +0.2m

nil nil

0438-1) 1250(-1) 2.2m 0.2m


Tidal Curve - VlissingenTidal Curve - Vlissingen

+1 +2 +3 +4 +5HW-1-2-3-4-5

0 2 431

0 21


VLISSINGEN (FLUSHING)5

LW0438


Tidal Curve - VlissingenTidal Curve - Vlissingen

+1 +2 +3 +4 +5HW-1-2-3-4-5

0 2 431

0 21


VLISSINGEN (FLUSHING)5

LW04381.0m


Solent PortsSolent Ports

• Times and heights are obtained by applying time and height differences to PORTSMOUTH.

• All ports 37 to 70 are listed on pages 323/324 (2A-90).

• Curves listed on pages xxii to xxiv using separate curves for each group of ports.

• Curves are based on Low Water.

• Obtain differences in the normal way.


Solent Port DifferencesSolent Port Differences

ENGLAND, SOUTH COAST


0000 0600 0500 110065 PORTSMOUTH and and and and 4.7 3.8 1.9 0.8

1200 1800 1700 2300

37 Bournemouth 50 43 1 52 -0240 +0055 -0050 -0030 -2.7 -2.2 -0.8 -0.338 Christchurch 50 43 1 45 -0230 +0030 -0035 -0035 -2.9 -2.4 -1.2 -0.2

39 Hurst Point 50 42 1 33 -0115 -0005 -0030 -0025 -2.0 -1.5 -0.5 -0.140 Lymington 50 46 1 32 -0110 +0005 -0020 -0020 -1.7 -1.2 -0.5 -0.143 Stansore Point 50 47 1 21 -0050 -0010 -0005 -0010 -0.9 -0.6 -0.2 -0.0

Isle of Wight45 Yarmouth 50 42 1 30 -0105 +0005 -0025 -0030 -1.6 -1.3 -0.4 0.046 Totland Bay 50 41 1 33 -0130 -0045 -0040 -0040 -2.0 -1.5 -0.5 0.148 Freshwater 50 40 1 31 -0210 +0025 -0040 -0020 -2.1 -1.5 -0.4 0.0

51 Ventnor 50 36 1 12 -0025 -0030 -0025 -0030 -0.8 -0.6 -0.2 +0.253 Sandown 50 39 1 09 0000 +0005 =0010 +0025 -0.6 -0.5 -0.2 0.053a Foreland (Slip) 50 41 1 04 -0005 0000 +0005 +0010 -0.1 -0.1 0.0 +0.154 Bembridge Hbr 50 42 1 06 -0010 +0005 +0020 0000 -1.6 -1.5 -1.4 -0.658 Ryde 50 44 1 07 -0010 +0010 -0005 -0010 -0.2 -0.1 0.0 +0.1


Stansore Point CurveStansore Point Curve

LW-1-3 -2-5 -4-7 -6 +1 +4+3+2 +6+5 +70 1 2 3 4 5

50 1 2 3 4

Bucklers HardStansore PointLeeFolly InnNewport

Range at PortsmouthSp 3.9mNp 1.9m


Lymington/Yarmouth CurveLymington/Yarmouth Curve

LW-1-3 -2-5 -4-7 -6 +1 +4+3+2 +6+5 +70 1 2 3 4 5

50 1 2 3 4

LymingtonYarmouth

Range at Portsmouth

Sp 3.9m 2.6mNp 1.9m


ExampleExample

• What time will the height of tide first rise to 3.0 metres at STANSORE POINT on 2 June?

• Portsmouth predictions LW 2140 1.7m, HW 0427 3.9m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Portsmouth 3.0m

Stansore Pt 2 Jun A





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Portsmouth 3.0m

Stansore Pt 2 Jun A

0427Z 2140Z 3.9m 1.7m 2.2m

15%Sp


Stansore Pt DifferencesStansore Pt Differences

ENGLAND, SOUTH COAST


0000 0600 0500 110065 PORTSMOUTH and and and and 4.7 3.8 1.9 0.8

1200 1800 1700 2300

37 Bournemouth 50 43 1 52 -0240 +0055 -0050 -0030 -2.7 -2.2 -0.8 -0.338 Christchurch 50 43 1 45 -0230 +0030 -0035 -0035 -2.9 -2.4 -1.2 -0.2

39 Hurst Point 50 42 1 33 -0115 -0005 -0030 -0025 -2.0 -1.5 -0.5 -0.140 Lymington 50 46 1 32 -0110 +0005 -0020 -0020 -1.7 -1.2 -0.5 -0.143 Stansore Point 50 47 1 21 -0050 -0010 -0005 -0010 -0.9 -0.6 -0.2 -0.0

Isle of Wight45 Yarmouth 50 42 1 30 -0105 +0005 -0025 -0030 -1.6 -1.3 -0.4 0.046 Totland Bay 50 41 1 33 -0130 -0045 -0040 -0040 -2.0 -1.5 -0.5 0.148 Freshwater 50 40 1 31 -0210 +0025 -0040 -0020 -2.1 -1.5 -0.4 0.0

51 Ventnor 50 36 1 12 -0025 -0030 -0025 -0030 -0.8 -0.6 -0.2 +0.253 Sandown 50 39 1 09 0000 +0005 =0010 +0025 -0.6 -0.5 -0.2 0.053a Foreland (Slip) 50 41 1 04 -0005 0000 +0005 +0010 -0.1 -0.1 0.0 +0.154 Bembridge Hbr 50 42 1 06 -0010 +0005 +0020 0000 -1.6 -1.5 -1.4 -0.658 Ryde 50 44 1 07 -0010 +0010 -0005 -0010 -0.2 -0.1 0.0 +0.1


Interpolation of HW TimesInterpolation of HW Times

0000 0100 0200 0300 0400 0500 0600

Times of HW at Portsmouth

Stansore Point Differences

-50 min -10 min-43m --37m -30m -23m -17m

0427

-20m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Portsmouth 3.0m

Stansore Pt 2 Jun A

0427Z 2140Z 3.9m 1.7m 2.2m

15%Sp-0020 -0008 -0.6m -0.2m

0407Z 2132Z 3.3m 1.5m

2232A



LW-1-3 -2-5 -4-7 -6 +1 +4+3+2 +6+5 +70 1 2 3 4 5

50 1 2 3 4



2232A



LW-1-3 -2-5 -4-7 -6 +1 +4+3+2 +6+5 +70 1 2 3 4 5

50 1 2 3 4



2232A

0415A


Non-European PortsNon-European Ports


PublicationsPublications

• Admiralty Tides Tables Volume 2 (Europe excluding United Kingdom and Ireland) Mediterranean Sea and Atlantic Ocean.

• Admiralty Tide Tables Volume 3 (Indian Ocean and South China Sea) & Volume 4 Pacific Ocean) (including TS Tables)

• Admiralty List of Radio Signals Volume 2 (Radio Time Signals).


Standard PortsStandard Ports

• List of standard ports inside front cover of ATT.

• Predictions are given in the Standard Time Zone for the country.

• If necessary times must be adjusted for Daylight Saving Time (DST) usually one hour ahead of standard time.

• Use standard tidal curve drawn for duration between 5 and 7 hours..


Standard Tidal CurveStandard Tidal Curve

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

00

42

84

63

21

00

24

12

36

+7-6-7

105

126

147


ExampleExample

• Calculate the height of tide at 0900 on 9th April at SINGAPORE.

• Page 2C-33 (Extract from Volume 3)

• HW 1011 2.5m LW 0407 1.1m





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Singapore 0900

-89 Apr





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Singapore 0900

-89 Apr

1011(-8) 0407(-8) 2.5m 1.1m 1.4m

6h 04m



+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

00

42

84

63

21

00

24

12

36

+7-6-7

105

126

147

1011(-8)



+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

00

42

84

63

21

00

24

12

36

+7-6-7

105

126

147

1011(-8)

2.4m



• Method is similar to European Secondary Ports but time differences not interpolated.

• Use sinusoidal curves as for standard port.• Times zones do not need adjustment except

for Daylight Saving Time (DST).• Seasonal changes are more likely and should

be incorporated.• Use standard tidal curve drawn for duration

between 5 and 7 hours.


ExampleExample

• Calculate at what time after 0600 local, the height of tide will first fall to 2.0 metres at BROTHERS LIGHT (4766a) on 11th August?


Brother’s Lt - DifferencesBrother’s Lt - DifferencesSUMATERA, NORTH EAST COAST

No PLACE TIME DIFF HEIGHT DIFF (MTRS)Lat Long MHW MLW MHWS MHWN MLWN MLWS N E (Zone –0700)

4718 SINGAPORE (see page 111) 2.8 2.1 1.2 0.5

Mandol4764 Bandong 0 32 103 18 -0007 -0007 +0.9 +0.5 +0.4 0.0

Gelam Strait4765 Tanjungbalai 0 59 103 26 -0051 -0051 +0.1 -0.1 +0.1 0.04766 Kenipaan 0 55 103 20 -0035 -0035 +0.1 +0.1 -0.2 -0.2

4766a Iyu Kecil (Brothers Light) 1 11 103 21 -0108 -0035 +0.2 +0.1 0.0 -0.1

Seasonal Changes in Mean Level

No. Jan 1 Feb 1 Mar 1 Apr 1 May 1 Jun 1 Jul 1 Aug 1 Sep 1 Oct 1 Nov 1 Dec 1

4663-4686 0.0 -0.1 -0.1 -0.1 0.0 +0.1 +0.1 0.0 0.0 0.0 0.0 0.04695 -0.1 -0.1 -0.1 -0.1 0.0 +0.1 +0.1 0.0 0.0 +0.1 +0.1 0.04704 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 0.0 0.0 +0.1 +0.1 0.04718-4749 +0.1 0.0 0.0 0.0 0.0 0.0 -0.1 -0.1 -0.1 0.0 +0.1 +0.14751-4763 +0.1 0.0 0.0 0.0 0.0 -0.1 -0.1 -0.1 -0.1 0.0 +0.1 +0.1

4764-4783 0.0 -0.1 -0.1 0.0 0.0 0.0 0.0 0.0 0.0 +0.1 +0.1 0.04784-4795 -0.1 -0.2 -0.2 -0.1 0.0 +0.1 +0.1 +0.1 0.0 +0.1 +0.1 0.0





STANDARD PORT

TIMES HEIGHTS

HW LW HW LW RANGE

Seasonal Change

Seasonal Change

SECONDARY PORT

Duration/DST

Standard Port -

Secondary Port +

Singapore 2.0m

-711 AugBrothers Lt

1335 1935 2.6m 0.6m 2.0m

+0.1m +0.1m

-0108 -0035 +0.2m -0.1m0.0m 0.0m

1227 1900 2.9m 0.6m

6hr 33min



+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

00

42

84

63

21

00

24

12

36

+7-6-7

105

126

147

1227

1510



+1 +2 +3 +4 +5 +6HW-1-2-3-4-5

00

42

84

63

21

00

24

12

36

+7-6-7

105

126

147

0955

0710

0640


Tidal StreamsTidal Streams


Visual Evidence of Visual Evidence of StreamStream


Sources of Tidal Stream Data Sources of Tidal Stream Data

• Tidal diamonds on charts

• Admiralty Tidal Stream Atlases

• Sailing Directions

• Admiralty Tide Tables Vol III & IV

• Port Guides

• Experience

• Pilots


Tidal DiamondTidal Diamond

201746Z

3.3


Tidal DiamondsTidal Diamonds

Tidal Streams referred to HW at PORTSMOUTH

HoursGeographical

Position5033.9’N129.2’W

5035.9’N122.9’W

5030.4’N116.6’W

5033.5’N116.6’W

6 094 1.9 0.9 129 1.3 0.6 084 1.2 0.6 072 2.3 1.2 -65 100 2.3 1.2 127 1.7 0.9 100 3.6 1.8 070 3.7 1.8 -54 102 2.7 1.3 125 1.8 0.9 100 4.5 2.2 080 3.3 1.6 -43 101 2.5 1.2 120 1.4 0.7 100 4.5 2.2 079 2.9 1.5 -32 102 1.8 0.9 109 0.7 0.4 100 3.5 1.7 077 2.4 1.2 -21 106 0.9 0.4 320 0.6 0.3 092 1.3 0.6 066 0.3 0.1 -1

HighWater

282 0.6 0.3 302 1.8 0.9 290 1.2 0.6 262 2.4 1.2 0

1 285 1.8 0.9 300 2.1 1.1 276 3.9 1.9 257 3.4 1.7 +12 286 2.3 1.2 300 1.6 0.8 276 4.3 2.1 252 3.8 1.9 +23 281 2.2 1.1 301 0.9 0.4 276 4.1 2.0 260 3.4 1.7 +34 283 1.6 0.8 290 0.2 0.1 276 3.1 1.5 255 2.3 1.2 +45 310 0.5 0.2 135 0.5 0.2 294 1.2 0.6 247 0.8 0.4 +56 090 0.9 0.5 129 1.1 0.6 068 0.7 0.4 075 1.6 0.8 +6

Aft

er H

igh

W

ater

Aft

er L

ow

Wat

er

Dir

ec

tio

ns

of

str

ea

ms

(d

eg

ree

s)

Ra

tes

at

sprin

g t

ide

s (k

no

ts)

Ra

tes

at

ne

ap

tid

es

(kn

ots

)D E F G


TS Atlas - TS Atlas - CoverageCoverage


Solent TS Atlas at HWSolent TS Atlas at HW


Tidal Stream AtlasTidal Stream Atlas

ISLE OF WIGHT

Ventnor

Sandown

Ryde

Portsmouth

Selsey B

ill

St C

athe

rine’

s Pt

Gosport

Bembridge Hr.

Foreland

NewportNewtown

W C

owes E Cowes

16,33

08,1

6

12,2

4

08,1707,14

Nab Tr

06,13

05,11

09,18

12,24

09,19

13,27

09,18

17,34

13,2706,12

04,08

12,22


Portsmouth - InterpolatorPortsmouth - Interpolator

0 02 04 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60

4.8

4.6

4.4

4.2

4.8

4.6

4.4

4.2

3.8

3.6

3.4

3.2

3.8

3.6

3.4

3.2

2.8

2.6

2.4

2.2

2.8

2.6

2.4

2.2

1.8

1.6

1.4

1.2

1.8

1.6

1.4

1.2

0 02 04 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60


ExampleExample

• What is the percentage of the Mean Spring Range and the predicted tidal stream in position 49o 50’N 001o 15’W (North of Pointe de Barfleur) at 1400A on 27th May?

• Channel TS Atlas based on Dover

Time Height

HW HWLW LW Range

1157 6.9m1933 0.6m 6.3m

1257A 1400 is 1 hr after HW


Percentage of MSRPercentage of MSR


6.3m - 3.2m 3.1m6.0m - 3.2m 2.8m

110%


1 Hr after HW DOVER1 Hr after HW DOVER


Dover InterpolatorDover Interpolator

0 02 04 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100

0 0 2 0 4 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100

COMPUTATION OF RATESTIDAL STREAM RATE (in tenths of a knot): assumed to vary with range of the tide at Dover

MeanRangeDover

MeanRangeDover

METRES METRES

7

6

5

4

3

6.86.66.46.2

5.65.45.2

4.84.64.44.2

3.83.6

2.82.62.42.2

2

Neaps

6.86.66.46.2

5.65.45.2

4.84.64.44.2

3.83.6

2.82.62.42.2

7

6

5

4

3

2

Neaps

SpringsSprings


Calculation of RateCalculation of Rate


6.3m - 3.2m 3.1m6.0m - 3.2m 2.8m

110%

Predicted Neap Rate 1.8 kts

Predicted Spring Rate 3.5 ktsIncrease 1.7 kts

Multiply increase by percentage

1.7kt + 110% = 1.9 kts

Direction WNW Total rate 1.8 + 1.9 = 3.7 kts


Sources of Tidal Stream Data Sources of Tidal Stream Data

• Tidal diamonds on charts

• Admiralty Tidal Stream Atlases

• Sailing Directions

• Port Guides

• Pilots Experience

• NP 629


NP 629 - Surface CurrentNP 629 - Surface Current


NP 629 - Tidal StreamNP 629 - Tidal Stream


CANADA, BRITISH COLUMBIA – SEYMOUR NARROWS

Lat 5008’N Long 12521’W

TIDAL STREAM PREDICTIONS (RATES IN KNOTS)

TIME ZONE +0800 POSITIVE(+) DIRECTION 180 NEGATIVE (-) DIRECTION 000

JANUARY FEBRUARYSLACK MAXIMUM SLACK MAXIMUM

Time Time Rate Time Time Rate Time Time Rate0025 0345 13.9 0110 0420 11.5 0150 0455 12.21 0715 1025 -11.9 16 0745 1100 -11.0 1 0810 1125 -12.51335 1610 8.2 1410 1655 7.4 1435 1730 10.3TH1900 2220 -10.9

F1950 2300 -8.6

SU2040 2345 -10.2

0115 0430 13.2 0150 0500 10.0 0240 0545 10.62 0755 1110 -11.8 17 0825 1140 -10.1 2 0855 1215 -11.81420 1700 8.3 1455 1740 6.9 1525 1830 10.1F1955 2310 -10.2

SA2040 2345 -7.3

M2140

0205 0520 12.1 0235 0545 8.5 0045 -9.03 0840 1155 -11.6 18 0900 1220 -9.2 3 0340 0640 9.01510 1800 8.5 1540 1830 6.5 0940 1305 -11.0SA2055

SU2135

TU16252250

1930 10.0

0005 -9.2 0035 -6.1 0150 -8.04 0300 0610 10.8 19 0325 0630 7.0 4 0450 0745 7.50925 1245 -11.3 0940 1305 -8.4 1035 1405 -10.3SU16052205

1900 8.7M

16302240

1925 6.3W

1725 2035 10.1

0105 -8.4 0130 -5.1 0005 0305 -7.75 0405 0710 9.4 20 0420 0720 5.7 5 0605 0855 6.61015 1340 -11.0 1020 1355 -7.7 1140 1515 -10.0M17002320

2005 9.2TU

17202345

2020 6.4TH

1825 2145 10.6

0215 -7.8 0240 -4.7 0115 0420 -8.06 0515 0815 8.3 21 0530 0820 4.8 6 0725 1000 6.31110 1440 -10.8 1105 1450 -7.4 1245 1620 -10.1TU1800 2110 10.1

W1810 2120 7.0

F1925 2245 11.4


Tidal Stream CurveTidal Stream Curve

Rate (knots)

Time0600 1200 1800 0000

16th January


Tidal Stream CurveTidal Stream Curve

Rate (knots)

Time0600 1200 1800 0000

+5

+10

-5

-10

16th January


Moderate TS WindowsModerate TS Windows

Rate (knots)

Time0600 1200 1800 0000

+5

+10

-5

-10

16th January


Any Questions?Any Questions?

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