Sea Conditions

Dover Strait, and the sea areas on either side, have a very distinctive sea disturbance with the area to the W of the Dover Strait greatly affected by rough to very rough seas with SW to W gales. During these periods, conditions on both sides of the English Channel can cause serious problems for cross-Channel traffic as there is only limited natural shelter available along most of the coastlines. Berthing and handling difficulties are often increased when the gale force winds veer to the NW. Gales from other directions are infrequent.

Strong winds from the NE and SW are greatly increased by funneling through the Dover Strait and give rise to higher seas on the Dover to Calais route than would be inferred from the gradient wind speed. This effect appears to be greater with NE winds. Storm surges only add to the problem and cross-channel traffic is liable to be restricted or discontinued due to the resultant high seas.

Routes

The outer approaches to the Thames Estuary are straddled by a lane of narrow, dangerous shoals, known as the Outer Banks, which run 50 miles NNE from Tail of the Falls to an unnamed shoal whose N extremity (52” 06’N, 1” 59’E) lies 15 miles E of Oхford Ness. There are a number of navigable channels through the shoals, the principal one being Falls Cap (51” 33’N, 1” 53’E), which is 8 miles wide and lies between South and North Falls. These channels and shoals are described in the outer passage directions.

There is an inner line of shoals, about 10 miles W of the outer line, which lie on the E edge of the shoals which encumber the estuary itself. The main ship channels lead between the latter shoals and are described from 11.37 to the end of the chapter.

Banks and channels are well marked by buoys and beacons. Landmarks standing on the low lying shores of the estuary are often obscured by poor visibility.

The main ship channels through the Thames Estuary and its approaches are shown opposite.

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. Narrow in-going streams of water, with speeds of up to 4 knots at spring tides, may be experienced in both entrances between 2 hours before HW. There are eddies off the breakwater heads and the variable directions of these eddies may give rise to turbulence in the entrances.

Tidal streams off the breakwaters and in Dover Harbour are given in 12 diagrams on the chart. The streams shown are surface streams and the sub-surface streams may differ appreciably.

II. Answer the following questions:

1. What types of lights may be exhibited from lighthouses?

2. What is the lateral system used for?

3. How is the ship hove into her berth?

4. What dangers may threaten the ship’s safety?

5. What information should be entered into the Log Book? Whom by?

III. Translate the following sentences into English:

1. Сизигийные приливы происходят в зависимости от положения луны, солнца и земли.

2. Какой пеленг этого маяка? Пеленг этого маяка 85'.

3. Цилиндрический буй, окрашенный в красную и белую клетку, ограждает восточную оконечность рифа (гряды камней).

4. Уведомьте капитана и примите все необходимые меры, если судно тянет якорь.

5. Судно должно швартоваться лагом левым бортом носом против течения.