1• © Capt. Yusuf ZORBA

BA, Secondary Port

Capt. Yusuf ZORBA

2• © Capt. Yusuf ZORBA

BA, Secondary Port• You learned that how can you calculate tide

times and heights for a specific port.

• Also, you learned that how can you calculate tide times and heights for secondary ports by US Tide Table’s.

• Our aime for this pratice;– Using Tide Tables for Secondary Port in

British Admiralty– Finding HW and LW times for Secondary Port– Finding HW and LW heights for Secondary

Port

3• © Capt. Yusuf ZORBA

BA, Secondary Port

4• © Capt. Yusuf ZORBA

BA, Secondary Port

• The method of finding the time and heights of HW and LW at any Secondary Port given in the Admiralty Tide Tables is by means of simple differences in times and heights from predictions for the Standart Port indicated, which is the most suitable, Standart Port.

5• © Capt. Yusuf ZORBA

BA, Secondary Port• Example 1: Find the times and heights of HW

and LW at Richborough for the PM rising tide on March, 02, 2001.

1. Find the secondary port in the Geographical Index at the back of ATT (Adm. Tide Table). Note its number.

Richborough : 99

2. Find the Standart Port names and numbers in ATT, Part I

Dover : 89

6• © Capt. Yusuf ZORBA

BA, Secondary Port3. Find the HW and LW times and heights at the

Standart Port for the required day. Enter in tables (called NP 204), boxes 1 to 4 and calculate the range for box 5.

7• © Capt. Yusuf ZORBA

BA, Secondary Port3. Find the HW and LW times and heights at the

Standart Port for the required day. Enter in tables (called NP 204), boxes 1 to 4 and calculate the range for box 5.

Standart Port HW LW HW LW RANGE

Seasonal Change

Std. Port

Differences

Seasonal Change

Sec. Port

Secondary Port

Duration

1511

- -

1013 6.0 1.5 4.5

8• © Capt. Yusuf ZORBA

BA, Secondary Port4. “Seasonal Change in Mean Level” table from

Part II , using its number and month find the Standart Port’s Seasonal Change.

Seasonal Changes In Mean Level for number 89 and 99 is same;

“ -0,1 ” We change its signed, because of Standart Port heights include the Seasonal

Change.

Standart Port HW LW HW LW RANGE

1 2 3 4 5

Seasonal Change

Std. Port6 6

Differences7 8 9 10

Seasonal Change

Sec. Port11 11

Secondary Port12 13 14 15

Duration16

1511 1013 6.0 1.5 4.5

0.1 0.1

9• © Capt. Yusuf ZORBA

BA, Secondary Port5. Note the time and height differences for the

secondary port and the related reference times and reference heights at the Standart Port.

10• © Capt. Yusuf ZORBA

BA, Secondary Port6. Interpolate between Secondary Port time

differences and height differences.

11• © Capt. Yusuf ZORBA

BA, Secondary Port6. Interpolate between Secondary Port time

differences and height differences.

Interpolation methods:

1. Using graph paper2. Using mathematical methods

12• © Capt. Yusuf ZORBA

6.1. Using graph paper for interpolation;

1800

1200

+10+20+30+40+50+60+70

1511

+15

1300

0700

+30

1013

13• © Capt. Yusuf ZORBA

6.1. Using graph paper for interpolation;

1800

1200

+10+20+30+40+50+60+70

1511

+15

1300

0700

+30

1013

0.0 m

2.0 m

4.0 m

6.0 m

- 4 - 3 - 2 - 1 0.0 + 1

14• © Capt. Yusuf ZORBA

Standart Port HW LW HW LW RANGE

1 2 3 4 5

Seasonal Change

Std. Port6 6

Differences7 8 9 10

Seasonal Change

Sec. Port11 11

Secondary Port12 13 14 15

Duration16

1511 1013 6.0 1.5 4.5

0.1 0.1

6.1. Using graph paper for interpolation;

15• © Capt. Yusuf ZORBA

6.1. Using graph paper for interpolation;

1800

1200

+10+20+30+40+50+60+70

1511

+15

1300

0700

+30

1013

0.0 m

2.0 m

4.0 m

6.0 m

- 4 - 3 - 2 - 1 0.0 + 1-3.1 -1.3

For 6.1

For 1.6

16• © Capt. Yusuf ZORBA

BA, Secondary Port

Standart Port HW LW HW LW RANGE

1 2 3 4 5

Seasonal Change

Std. Port6 6

Differences7 8 9 10

Seasonal Change

Sec. Port11 11

Secondary Port12 13 14 15

Duration16

1511 1013 6.0 1.5 4.5

0.1 0.1

00:15 00:30 -3.1 -1.3

And we complete in boxes 7, and 8, 9, 10.

17• © Capt. Yusuf ZORBA

6.2. Using mathematical methods

We will make a interpolation for secondary port differences.

For times;12:00 to 18:00 if +00:15 to +00:15And our HW time is 15:11 we can say that is

same (+00:15)

07:00 to 13:00 if +00:30 to +00:30And our LW time is 10:13 we can say that is same

(+00:30)And we enter this results into boxes #7 and #8.

18• © Capt. Yusuf ZORBA

6.2. Using mathematical methods

We will make a interpolation for secondary port differences.

For heights;For HW 5.3 to 6.8 if – 2.6 to –

3.4and our height is 6.1 = (0.8 x 0.8)/1.5 = 0.46

so, our differences for HW (-2.6)+(-0.46)= ~ -3.1

For LW 0.8 to 2.1 if – 0.7 to – 1.7And our height is 1.6 = (0.8 x 1.0)/1.3 = 0.62

And our differences for HW (-0.7)+(-0.62)= ~ -1.3

19• © Capt. Yusuf ZORBA

And we complete in boxes 7, and 8, 9, 10.7. Using Secondary Port number to locate the right

line, find and enter the Secondary Port’s Seasonal Change for the month in boxes 11.Richborough : 99

8. Apply differences to Standart Port times and heights to find times at the Secondary Port (boxes 12-15)

BA, Secondary Port

Standart Port HW LW HW LW RANGE

1 2 3 4 5

Seasonal Change

Std. Port6 6

Differences7 8 9 10

Seasonal Change

Sec. Port11 11

Secondary Port12 13 14 15

Duration16

1511 1013 6.0 1.5 4.5

0.1 0.1

00:15 00:30 - 3.1 - 1.3

- 0.1 - 0.1

15:26 10:43 2.9 0.2

- - - - -

20• © Capt. Yusuf ZORBA

BA, Secondary Port• Example 1: Find the times and heights of HW

and LW at Richborough for the PM rising tide on March, 02, 2001.

• Richborough March, 02, 2001

Time Height10:43 0.215:26 2.9