Tides revision lrg

Grunt Productions 2007
Tides and TidalTides and Tidal
StreamsStreams
A Brief By Lance GrindleyA Brief By Lance Grindley

Reach
Hook
Calshot
Black Jack
Castle Point
Calshot Spit
North Thorn
Bourne 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

TidalTidal
HeightsHeights
andand
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
Draught
Minimum
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 Datum
4m
HoT
MHWS
7m
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 Predictions
ENGLAND - PORTSMOUTH
Lat 50°48’N Long 1°07’W
TIME ZONE UT (GMT) TIMES AND HEIGHTS OF HIGH AND LOW WATERS YEAR 1998
JUNE JULY
Time m Time m Time m Time m
0338 4.1 0301 4.3 0458 0.8 0435 0.9
1 0911 1.4 16 0838 1.1 1 1144 4.8 16 1119 4.6
1819 4.1 1543 4.4 1723 0.6 1657 0.7M
2140 1.7
F
2109 1.3
M TU
• 2347 4.7
0427 3.9 0356 4.2 0015 4.8 0515 0.8
2 1008 1.6 17 0937 1.3 2 0539 0.8 17 1200 4.6
1715 4.0 1641 4.3 1227 4.7 1738 0.6TU
2244 1.8
SA
2213 1.4
TU
1803 0.6
W
0527 3.7 0459 4.1 0056 4.7 0027 4.7
3 1114 1.8 18 1044 1.3 3 0618 0.8 18 0555 0.6
1819 3.9 1747 4.3 1306 4.7 1242 4.7W
2354 1.9
SU
2324 1.5
W
1840 0.7
TH
1817 0.5
0638 3.7 0609 4.1 0133 4.7 0108 4.8
4 1221 1.8 19 1157 1.3 4 0654 0.9 19 0635 0.6
1924 4.0 1857 4.3 1343 4.5 1324 4.7TH M TH
1914 0.8
F
1857 0.5
0058 1.8 0037 1.4 0208 4.6 0150 4.8
5 0748 3.8 20 0722 4.2 5 0728 1.1 20 0716 0.6
1320 1.7 1307 1.2 1419 4.4 1407 4.7F
2019 4.1
SA
2003 4.5
F
1946 1.0
SA
1939 0.6
0151 1.6 0144 1.2 0243 4.5 0233 4.7
6 0841 3.9 21 0830 4.3 6 0802 1.3 21 0800 0.8
1408 1.5 1409 1.1 1455 4.2 1452 4.5TU
2105 4.2
SU
2103 4.6
SA
2019 1.2
SU
2023 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 RANGES
Springs 3.9m
Neaps 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
MEAN RANGES
Springs 3.9m
Neaps 1.9m
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 0800
523 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
N W Zone UT (GMT)
0200 0800 0300 0800
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
N W Zone UT (GMT)
0200 0800 0300 0800
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
N W Zone UT (GMT)
0200 0800 0300 0800
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
N W Zone UT (GMT)
0200 0800 0300 0800
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
MEAN RANGES
Springs 12.2m
Neaps 6.0m
AVONMOUTH
10 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
MEAN RANGES
Springs 12.2m
Neaps 6.0m
AVONMOUTH
10 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
N E Zone -0100
0300 0900 0400 1000
1523 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 +0.1
1528-1571 0.0 0.0 -0.1 -0.1 -0.1 -0.1 0.0 0.0 0.0 +0.1 +0.1 +0.1
1572 1581a 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 0.0 +0.1 +0.1 0.0 0.0
1582-1595a 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
N E Zone -0100
0300 0900 0400 1000
…(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
N E Zone -0100
0300 0900 0400 1000
…(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 TideIjmuiden - Height of Tide
DifferencesDifferences
NETHERLANDS
N E Zone -0100
0300 0900 0400 1000
…(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
MEAN RANGES
Springs 4.5m
Neaps 3.0m
VLISSINGEN (FLUSHING)
5
LW
0438

Tidal Curve - VlissingenTidal Curve - Vlissingen
+1 +2 +3 +4 +5HW-1-2-3-4-5
0 2 431
0 21
MEAN RANGES
Springs 4.5m
Neaps 3.0m
VLISSINGEN (FLUSHING)
5
LW
04381.0m

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
N W Zone UT (GMT)
0000 0600 0500 1100
65 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 -0.3
38 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 -0.1
40 Lymington 50 46 1 32 -0110 +0005 -0020 -0020 -1.7 -1.2 -0.5 -0.1
43 Stansore Point 50 47 1 21 -0050 -0010 -0005 -0010 -0.9 -0.6 -0.2 -0.0
Isle of Wight
45 Yarmouth 50 42 1 30 -0105 +0005 -0025 -0030 -1.6 -1.3 -0.4 0.0
46 Totland Bay 50 41 1 33 -0130 -0045 -0040 -0040 -2.0 -1.5 -0.5 0.1
48 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 +0.2
53 Sandown 50 39 1 09 0000 +0005 =0010 +0025 -0.6 -0.5 -0.2 0.0
53a Foreland (Slip) 50 41 1 04 -0005 0000 +0005 +0010 -0.1 -0.1 0.0 +0.1
54 Bembridge Hbr 50 42 1 06 -0010 +0005 +0020 0000 -1.6 -1.5 -1.4 -0.6
58 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 Hard
Stansore Point
Lee
Folly Inn
Newport
Range at Portsmouth
Sp 3.9m
Np 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
Lymington
Yarmouth
Range at Portsmouth
Sp 3.9m
2.6m
Np 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
N W Zone UT (GMT)
0000 0600 0500 1100
65 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 -0.3
38 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 -0.1
40 Lymington 50 46 1 32 -0110 +0005 -0020 -0020 -1.7 -1.2 -0.5 -0.1
43 Stansore Point 50 47 1 21 -0050 -0010 -0005 -0010 -0.9 -0.6 -0.2 -0.0
Isle of Wight
45 Yarmouth 50 42 1 30 -0105 +0005 -0025 -0030 -1.6 -1.3 -0.4 0.0
46 Totland Bay 50 41 1 33 -0130 -0045 -0040 -0040 -2.0 -1.5 -0.5 0.1
48 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 +0.2
53 Sandown 50 39 1 09 0000 +0005 =0010 +0025 -0.6 -0.5 -0.2 0.0
53a Foreland (Slip) 50 41 1 04 -0005 0000 +0005 +0010 -0.1 -0.1 0.0 +0.1
54 Bembridge Hbr 50 42 1 06 -0010 +0005 +0020 0000 -1.6 -1.5 -1.4 -0.6
58 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
Bucklers Hard
Stansore Point
Lee
Folly Inn
Newport
Range at Portsmouth
Sp 3.9m
Np 1.9m
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
Bucklers Hard
Stansore Point
Lee
Folly Inn
Newport
Range at Portsmouth
Sp 3.9m
Np 1.9m
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
0
0
4
2
8
4
6
3
2
1
0
0
2
4
1
2
3
6
+7-6-7
10
5
12
6
14
7

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
0
0
4
2
8
4
6
3
2
1
0
0
2
4
1
2
3
6
+7-6-7
10
5
12
6
14
7
1011(-8)

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5
0
0
4
2
8
4
6
3
2
1
0
0
2
4
1
2
3
6
+7-6-7
10
5
12
6
14
7
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 - Differences
SUMATERA, 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
Mandol
4764 Bandong 0 32 103 18 -0007 -0007 +0.9 +0.5 +0.4 0.0
Gelam Strait
4765 Tanjungbalai 0 59 103 26 -0051 -0051 +0.1 -0.1 +0.1 0.0
4766 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 0.0
4695 -0.1 -0.1 -0.1 -0.1 0.0 +0.1 +0.1 0.0 0.0 +0.1 +0.1 0.0
4704 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0 0.0 0.0 +0.1 +0.1 0.0
4718-4749 +0.1 0.0 0.0 0.0 0.0 0.0 -0.1 -0.1 -0.1 0.0 +0.1 +0.1
4751-4763 +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 0.0
4784-4795 -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 -0.1m
0.0m 0.0m
1227 1900 2.9m 0.6m
6hr 33min

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5
0
0
4
2
8
4
6
3
2
1
0
0
2
4
1
2
3
6
+7-6-7
10
5
12
6
14
7
1227
1510

+1 +2 +3 +4 +5 +6HW-1-2-3-4-5
0
0
4
2
8
4
6
3
2
1
0
0
2
4
1
2
3
6
+7-6-7
10
5
12
6
14
7
0955
0710
0640

Tidal StreamsTidal Streams

Visual Evidence ofVisual Evidence of
StreamStream

Sources of Tidal Stream DataSources 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
Hours
Geographical
Position
50°33.9’N
1°29.2’W
50°35.9’N
1°22.9’W
50°30.4’N
1°16.6’W
50°33.5’N
1°16.6’W
6 094 1.9 0.9 129 1.3 0.6 084 1.2 0.6 072 2.3 1.2 -6
5 100 2.3 1.2 127 1.7 0.9 100 3.6 1.8 070 3.7 1.8 -5
4 102 2.7 1.3 125 1.8 0.9 100 4.5 2.2 080 3.3 1.6 -4
3 101 2.5 1.2 120 1.4 0.7 100 4.5 2.2 079 2.9 1.5 -3
2 102 1.8 0.9 109 0.7 0.4 100 3.5 1.7 077 2.4 1.2 -2
1 106 0.9 0.4 320 0.6 0.3 092 1.3 0.6 066 0.3 0.1 -1
High
Water
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 +1
2 286 2.3 1.2 300 1.6 0.8 276 4.3 2.1 252 3.8 1.9 +2
3 281 2.2 1.1 301 0.9 0.4 276 4.1 2.0 260 3.4 1.7 +3
4 283 1.6 0.8 290 0.2 0.1 276 3.1 1.5 255 2.3 1.2 +4
5 310 0.5 0.2 135 0.5 0.2 294 1.2 0.6 247 0.8 0.4 +5
6 090 0.9 0.5 129 1.1 0.6 068 0.7 0.4 075 1.6 0.8 +6
AfterHigh
Water
AfterLow
Water
Directionsofstreams(degrees)
Ratesatspringtides(knots)
Ratesatneaptides(knots)
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
SelseyBill
StCatherine’sPt
Gosport
Bembridge Hr.
Foreland
Newport
Newtown
W
C
ow
es
E
C
ow
es
16,33
08,16
12,24
08,17
07,14
Nab Tr
06,13
05,11
09,18
12,24
09,19
13,27
09,18
17,34
13,27
06,12
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
MEAN RANGES
Springs 6.0m
Neaps 3.2m
6.3m - 3.2m 3.1m
6.0m - 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 RATES
TIDAL STREAM RATE (in tenths of a knot): assumed to vary with range of the tide at Dover
Mean
Range
Dover
Mean
Range
Dover
METRES METRES
7
6
5
4
3
6.8
6.6
6.4
6.2
5.6
5.4
5.2
4.8
4.6
4.4
4.2
3.8
3.6
2.8
2.6
2.4
2.2
2
Neaps
6.8
6.6
6.4
6.2
5.6
5.4
5.2
4.8
4.6
4.4
4.2
3.8
3.6
2.8
2.6
2.4
2.2
7
6
5
4
3
2
Neaps
SpringsSprings

Calculation of RateCalculation of Rate
MEAN RANGES
Springs 6.0m
Neaps 3.2m
6.3m - 3.2m 3.1m
6.0m - 3.2m 2.8m
110%
Predicted Neap Rate 1.8 kts
Predicted Spring Rate 3.5 kts
Increase 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 DataSources 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 50°08’N Long 125°21’W
TIDAL STREAM PREDICTIONS (RATES IN KNOTS)
TIME ZONE +0800 POSITIVE(+) DIRECTION 180 NEGATIVE (-) DIRECTION 000
JANUARY FEBRUARY
SLACK MAXIMUM SLACK MAXIMUM
Time Time Rate Time Time Rate Time Time Rate
0025 0345 13.9 0110 0420 11.5 0150 0455 12.2
1 0715 1025 -11.9 16 0745 1100 -11.0 1 0810 1125 -12.5
1335 1610 8.2 1410 1655 7.4 1435 1730 10.3TH
1900 2220 -10.9
F
1950 2300 -8.6
SU
2040 2345 -10.2
0115 0430 13.2 0150 0500 10.0 0240 0545 10.6
2 0755 1110 -11.8 17 0825 1140 -10.1 2 0855 1215 -11.8
1420 1700 8.3 1455 1740 6.9 1525 1830 10.1F
1955 2310 -10.2
SA
2040 2345 -7.3
M
2140
0205 0520 12.1 0235 0545 8.5 0045 -9.0
3 0840 1155 -11.6 18 0900 1220 -9.2 3 0340 0640 9.0
1510 1800 8.5 1540 1830 6.5 0940 1305 -11.0SA
2055
SU
2135
TU
1625
2250
1930 10.0
0005 -9.2 0035 -6.1 0150 -8.0
4 0300 0610 10.8 19 0325 0630 7.0 4 0450 0745 7.5
0925 1245 -11.3 0940 1305 -8.4 1035 1405 -10.3SU
1605
2205
1900 8.7
M
1630
2240
1925 6.3
W
1725 2035 10.1
0105 -8.4 0130 -5.1 0005 0305 -7.7
5 0405 0710 9.4 20 0420 0720 5.7 5 0605 0855 6.6
1015 1340 -11.0 1020 1355 -7.7 1140 1515 -10.0M
1700
2320
2005 9.2
TU
1720
2345
2020 6.4
TH
1825 2145 10.6
0215 -7.8 0240 -4.7 0115 0420 -8.0
6 0515 0815 8.3 21 0530 0820 4.8 6 0725 1000 6.3
1110 1440 -10.8 1105 1450 -7.4 1245 1620 -10.1TU
1800 2110 10.1
W
1810 2120 7.0
F
1925 2245 11.4

Tidal Stream CurveTidal Stream Curve
Rate (knots)
Time
0600 1200 1800 0000
16th
January

Tidal Stream CurveTidal Stream Curve
Rate (knots)
Time
0600 1200 1800 0000
+5
+10
-5
-10
16th
January

Moderate TS WindowsModerate TS Windows
Rate (knots)
Time
0600 1200 1800 0000
+5
+10
-5
-10
16th
January

Any Questions?Any Questions?

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