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78
Question.
PORTS AND HARBOURS OF THE BRITISH EMPIRE:
1. At bar or entrance, what | (1) 600 ft.
to:--
(1) the minimum width f (2) the
minimum
navigable depth, L.W,O.S.T. ?
(Note-If between the en-
trance and the deep sea there are bars or shoals where a lesser depth occurs than the mini- mum indicated above, a List of such obstructions and of the depths over them (L.W.0.8.T) should be given)
2. In the approach channel from bar or entrance to berthing accommodation, what is :-
(the minimum and
maximum width f the minimum and maximum depth, L.W.O.S.T.?
3. What is-
(1) the rise and fall of tides
(a) ordinary springs, (b) ordinary neaps ? (2) the rise of ordinary neaps above L.W.0.8.T.?
4. What is the maximum available depth of water- (a) at piers or wharves,
L.W.O.S.T.?
(b) in the case of enclosed docks, in the en- trance locks, if any, and at dock quays, H.W.O.N.T.?
Aden.
(2) 30-31 ft. (L.W.O.S.T.).
Dredged channel from outer harbour to inner harbour:-
Width, 600 ft. Depth, 30-31 ft.
(L.W.O.S.T.).
Bombay.
Width, 2 miles. Depth, 36 ft. (L.W.O.S.T.) to a point east of midille ground.
Calcutta,
The width of the channel at the entrance, Saugor, is 2 miles. Higher up the width is irregular; at Jalling- ham and Kulpi anchorages it is 14 miles and at Diamond Harbour anchorage + uile.
The portion of the river which separates the Port of Calcutta
from the sea contains a number of bars on which the depth of water varies from time to time, and which are crossed at or near high water. As regards the width of the navigable channel, the passage of vessels is restricted at certain times and places to channels 330-500 ft. in width. The deepest draught vessel that has up to the present navigated the Hooghly drew 29 ft. 3 ins. In 1914-15 five vessels of over 28 ft., aud 24 vessels between 27 and 28 ft. passed down the river. It may be mentioned, however, that whereas smaller vessels occupy only about 7 hours in steaming down the river the delaya to vessels of deep draught (i... 25 ft. and over) amount on an average to 12 hours and sometimes much more.
From middle ground the See answer to question 1.
width decreases to three-
(1) () Ordinary springs, 7 ft. (1)
(b) Ordinary neaps, 4 ft.
G ins.
quarters of a mile with a minimum depth of 21 to 22 ft. (L.W.0.8.T) directly off the dock channel. The approach channel to the dock is 1,200 ft. wide and is dredged to a depth of 21 ft. (L.W.0.S.T.).
Spring tides, mean runge 14 ft. 3 ins.
(b) Neap tides,
range 6 ft.
(2) Rise of ordinary neaps above L.W.O.S.T., 11 ft. 6 ins.
(2) Rise of ordinary
No enclosed docks. Large vessels lie in inner basin, which is dredged to 30-31 ft. (L.W.O.S.T.).
mean
neaps
above L.W.O.S.T., 10 ft. 3 ins, above datum.
(a) The maximum available depth at the quays is 28 ft. (L.W.O.S.T.) alongside the outer wall of the Alexandra Dock.
(b) In the enclosed docks the maximum available depth is:- (1) 34 ft. 3 ins. (H.W.O.N.T.) on the inner sill of the entrance lock to the Alexandra Dock.
(2) 36 ft. 3 ins. (H.W.O.N.T.)
in the Alexandra Dock.
(1) (a) Ordinary springs:-
Saugor (at mouth of
river)
Calcutta,
(b) Ordinary neaps :-
Sangor
Calcutta
Western entrance-
Width -
Depth
·
Colombo.
Ft. 800 __40 (L.W.O.S.T.). Ft.
700
INDIA AND THE EASTERN COLONIES.
Hong Kong.
Eastern entrance (Lyfemun), width, 1,100 ft.; depth, 78 ft. (L.W.O.S.T.). Western entrance (Sulphur Channel), width, 1,100 ft.; depth, 54 ft. (L.W.Ó.S.T.).
35 (L.W.O.S.T.). Western entrance (Kap Sing Munj,
width, 650 ft.; depth, 84 ft. (L.W.0.8.T.). All widths and depths are taken from between the 30 ft. Jine of soundings. The approach to Lybomun shallows sea. wards to a lenkt depth of 42 ft. (L.W.O.S.T.), Sulphur channel to 60 ft. (L.W.O.S.T.), Kap Sing Mun to 49 ft. (L.W.O.S.T.).
ฯ
Singapore.
140
79
At Onter Roadstead (sheltered anchor- age) depth from 36 to 72 ft. (LW.0.ST.)
Eastern entrance-
Width - Depth
Channels from entrances to anchorage | Eastern approach :—
Western-
Width
Ft. 630
Minimum depth
Eastern-
Width Minimum depth
31 (L.W.OS.T.).
560
30 (L.W.OS.T.).
Ft. Ing.
(1) (a) Ordinary springs
(b) Ordinary neaps
22 ft. 8 ins.
(2)
. 14 3
- 11 8
-
6 6
7 0
(2) As the river level is affected considerably by freshets, L.W.O.S.T. varies during the year and is not, therefore, used as a datum. At Saugor the rise of neaps is about 12 ft. 3 ins. above the lowest low water. The rise of ordinary neaps at Calcutta is 12 ft. above datum 10 ft, above the lowest low water.
or
(a) The average depth along- side the old Jetty berths is about 18 ft. below lowest low water. At the new, or Nos. 7, 8 and 9 Jetty berths (No. 9 being that completed in 1914) the depth varies from 25 ft. to 30 ft. The depth at the New Garden Reach Jetties now under construction will be 40 ft. (se answer to question 13). (6) The depth of the sill at the entrance lock to the docks is 19 ft. below lowest low water, or 29 ft. at H.W.O.N.T.
The depth in the docks, which is maintained by pumping,
is 29 ft. 6 ins.
No enclosed docks. All vessels of any size lie out under the shelter of the breakwaters and are loaded or die- charged from lighters. The whole ares within the limit of dredging has a depth of 30 ft. (L.W.O.S.T.) and parts are being deepened to 33 ft. and ' 30 ft. (L.W.0.3.T.).
Width, 1,100 ft. to 8,000 ft. Depth, 36 ft. to 78 ft. (L.W.O.S.T.). Western approach :--
Width, 1,100 ft. to 1,200 ft.
Depth (from Sulphat Chunnel), 23 ft.
to 36 ft. (L.W.O.ST.).
Depth (from Kap Sing Mun), 23 ft. to
132 ft. (L.W.0.S.T.J.
Tides are classed as springs and neaps. Rise and fall-Springs, 7 ft. to 8 ft.; Neaps, 4 ft. to 5 ft.
Tide does not always apply. At certain seasons one H.W, and one L.W. obtain at this port. At other times (largely induenced by the monsoon) one H.W. and one L.W. occur followed by a second H.W. and L.W. of greatly diminished range. There is sometimes only as much a 6 ins. difference between the high and low water of this inferior tide.
No enclosed docks. Maximum available depth at quays, 32 ft.
(L.W.O.S.T.) at Holt's Wharf, Kowloon.
(a) Eastern Entrance. Width, 450 yds.
Depth, 42 to 60 ft. (L.W.0.S.T.).
(b) Western Entrance. Width, 200 yds.
Depth, 60 ft. (L.W.O.S.T.).
(1) (u) Ordinary springs, 9 ft,
(b) Ordinary neaps, 3 ft. 6 ins neaps
above
(2) Rise of ordinary
L.W.O.S.T. 6 ft.
No enclosed docka,
Maximum available depth at quaye at
present, 33 ft. (L.W.O.S.T.).
A 2