Weaken слабый Other words and expressions

flood rise нарастание паводка

freshet паводок; половодье

mean neap rise средняя высота квадратурного прилива

mean rise of tide средняя высота прилива

mean spring rise средняя высота сизигийного прилива

neap rise высота квадратурного прилива

tidal rise высота прилива; повышение уровня воды при приливе; прилив

stream течение

~ of current направление течения

ebb tide ~ отливное течение

flood tide ~ приливное течение

in-going ~ входящее течение

out-going ~ выходящее течение

perceptible ~ ощутимое течение

rotary ~ водоворот; вращательный

semidiurnal tidal stream приливо-отливное течение с полусуточным периодом

side ~ боковой поток

tidal-stream приливо-отливное течение

strength сила

considerable ~ значительная сила

predicted ~ предсказуемая сила

significant ~ значительная сила

great ~ большая сила

of little ~ небольшой силы

ebb ~ (максимальная) скорость отливного течения

flood ~ (максимальная) скорость приливного течения

flow ~ энергия потока

TEXT

1. Between Selsey Bill (50º 23'N, 0º 47' W) and Royal Sovereign Shoals, 45 miles E, the difference at which the streams begin is about 1 hour. Between Royal Sovereign Shoals and Dungeness the difference at which the streams begin is about 4 hours, a much greater change of time with distance and this can be of advantage to vessels on passage.

2. The rates of streams vary with the width of the channel and are at their strongest in the most narrow parts. Springs rates may be up to 4 kn in the Dover Strait but where the channel is wider the rates rarely exceed 2½ kn.

3. When there is a S-going stream off the Thames Estuary the tide is rising locally and when there is a N-going stream the tide is falling locally at Dover. Near the land the streams are running in the direction of the coast, but the times at which they begin may differ considerably from the times a few miles offshore.

4. In the S part of the North Sea the tidal streams tend to set obliquely across the shoals. The streams do not necessarily change at local HW or LW and are often at their greatest rate at local HW. The wind has a considerable effect on the strength and direction of the tidal streams.

5. The E-going stream generally sets NE towards the bays between Selsey Bill and Dungeness, but the W-going stream sets SW clear of the land. The E onshore set is of little consequence to E bound vessels, but could have a considerable effect on W bound vessels proceeding against it.

6. Tidal streams are strong between the piers and can reach 6 kn. The in-going stream continues until about 1½ hours after HW at springs and 30 minutes after HW at neaps. The out-going stream continues until 4 hours before HW.

7. After heavy rain the out-going stream is increased and the in-going stream correspondingly reduced and in extreme conditions the tide may be maintained or exceeded. Tide gauges are situated at the heads of East Pier and West Pier and County Wharf.

8. The W-going stream begins 2 hours before local HW and flows for about 6 hours. This stream is deflected SW by East Breakwater, across and into the entrance and can attain 2 kn at springs. The SW-going stream is then deflected into the harbour and diverted NE from the head of West Pier towards the head of East Pier, causing a marked set between the pierheads.

9. Within the harbour the in-going stream sets almost entirely up Western Arm, with little change in rate except where the arm narrows at Soldier’s Point ( 3 cables NNW of West Pierhead),where it can attain 4 kn at springs.

10. At the entrance both the in-going and out-going tidal streams attain a rate of 2 kn at springs. The in-going stream begins at about -0545 HW Dover and the out-going stream about +0100 HW Dover. The rate of the streams decreases in the N of the harbour.

11. Tidal streams are weak near the shores of Rye Bay. Due to the great change in times between Royal Sovereign Shoals and Dungeness, the times at which the streams begin in all parts of the bay is doubtful. The tidal streams are strong in the entrance to Rye Harbour. The in-going stream is stronger than the out-going, attaining 3½ kn at springs and up to 5 kn on occasions.

12. Close inshore the tidal streams follow the land so the E-going stream runs N close inshore in East Road, 4 miles NNE of Dungeness, then turns E towards Folkestone, while the W-going stream runs W from Folkestone and then S towards Dungeness. The streams are weak in both directions.

13. The spring rate on the ENE-going stream is 2 kn and on the WSW-going stream 1½ kn. When the stream sets ENE an eddy runs W along the coast from Copt Point and sets strongly towards the head of South Quay, on the S side of the entrance to outer Harbour.

14. The tidal streams in the entrances vary greatly from hour to hour. Either entrance, at almost any time, may be subject to an in-going stream in one part and an out-going stream in another. There are eddies off the breakwater heads and rise to turbulence in the entrances.

15. Between Cap d’Antifer and Roc Vaudieu, 3 miles NE, an eddy known locally as “Les Hardiers”, runs E during the whole of the W-going stream, extending up to 1 mile offshore. A second eddy runs W during the E-going stream, E of Pointe du Chicart.

16. Off the entrance the NNE-going stream commences at about 5½ hours before HW Fecamp and runs to HW Fecamp. At springs the rate may reach up to 5 kn. The SSW-going stream commences 30 minutes after HW Fecamp. Its rate is weaker than the NNE –going stream. About 150 m within the entrance both the in-going and out-going streams run at 1 kn at springs and ½ kn at neaps.

17. The LW slack period is less than the HW slack period. In good weather the tidal stream does not exceed ½ kn between 1 hour before and HW, even at springs. With W winds HW may be up to 45 minutes late and with SE winds up to 20 minutes early.

18. As the Baie de Somme is approached the NE-going stream close inshore becomes an in-going stream with a mean rate of 2½ kn. To the SW the rates are weaker and at Ault attain a rate of only 1¼ kn.

19. Off the entrance to the Baie de Somme the tidal streams are rotary anti-clockwise, and appear to attain their maximum rate as the drying banks are either just covered or just about to be uncovered. The in-going stream begins in the entrance and outer channels soon after local LW and off Poite du Hourdel about 30 minutes later.

20. At a position 5 cables NW of the jetty heads the in-going stream runs ENE, beginning 2¾ hours before HW Calais and the out-going stream runs WSW, beginning 3½ hours after HW Calais. At springs the maximum rate on the in-going stream is 3 kn and on the out-going stream is 2 kn. There is probably little or no stream between the jetties or in the harbour.

21. The timing and strength of the tidal streams may differ significantly because of the meteorological conditions. At springs the predicted strength of the tidal stream may be exceeded by 25 per cent and at neaps by as much as 40 per cent and the timing of slack water may vary by 2 hours.

22. About 5 cables off the entrance to Port Est, the ENE-going stream commences 2 hours before local HW, obtaining its maximum rate at HW, which at springs is 2½ kn . HW slack occurs 4 hours after HW, thence the WSW-going stream commences 15 minutes later reaching its maximum rate, at springs 1 kn, 6 hours after HW. With W winds slack extends up to 25 minutes, but with E winds reduces to as little as 10 minutes.

23. On the Bancs de Flandre the tidal streams set NE and SW, with a rapid turn of the tide. The maximum rate on the NE-going stream is 2½ kn, on the SW-going stream the rate is generally less. Closer inshore the streams set in the direction of the coast, reaching their maximum rate about the time of local HW. The spring rate in both directions is 2 kn.

24. HW Oostende is about 55 minutes before HW Vlissingen. The ENE-going stream begins about 2¾ hours before HW Vlissingen, maximum rate 1 kn . The WSW-going stream begins 2 ½ hours after HW Vlissingen, maximum rate 1 kn. The streams generally set along the line of the coast, except at the turn from the ENE-going stream to the WSW-going stream when they tend away from the coast.

25. The times at which streams begin and their directions vary considerably in the different parts of the estuary. Close to the river entrance spring rates are 2½ kn and at neaps 1 kn, but further to seaward the rates are less. Both the rate and direction are affected by strong winds.

26. Tidal streams run strongly off the entrance and there is eddy with the in-going stream, but there is no special difficulty in entering the harbour.

27. The tidal stream runs SE/NW across the approach to Aberdeen, with a spring rate in each direction of 1½ - 2 kn, which also applies in the anchorage. Off the entrance the stream is weak. The SE-going stream commences at –0450 HW Aberdeen and the NW-going stream at +0110 HW Aberdeen. Within the breakwaters the River Dee runs with considerable strength particularly during freshets and may achieve 6 kn. The strong outflow may continue even on a flood tide. In Tidal Harbour there is a weak anti-clockwise current.

28. When Annat Bank is dry the stream runs strongly through the whole length of the channel, but as the bank covers they spread out, run across it and are weaker at the outer end of the channel.

29. As Inchkeith is approached the tidal streams are more or less rotary, clockwise. They change direction rapidly when weak and are strongest in the directions 235º and 055º with springs rates of ¾ kn and 1 kn respectively. The tides and tidal streams are greatly affected by the meteorological conditions in the North Sea and by melting snow and rain inland.

30. In the vicinity of North Wall and the immediate approach to Main Basin, circular streams, with rates not exceeding ½kn, occur on both the in-going and out-going streams. A strong SW set has been reported on the N side of Middle Jetty, one hour before HW.