22 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



The entrance lock is on the east side, near the south end. The 

 length is 350 feet by a breadth of 36 feet, with a depth of 

 36 feet of water over the outer sill at average springs, and 

 25 feet at average neap tides. The inner sill is 8 feet above the 

 outer sill. 



The lock is fitted with three pairs of timber gates, and one 

 pair of iron sea-gates. 



The position of the lock is practically at right angles to the 

 stream, straight jetties being carried out so as to forma trumpet- 

 shaped entrance 300 feet wide and some 210 feet deep. 



A dry dock is placed on the east side, between the lock and 

 the south end ; the length is 532 feet from the gates to the head 

 of the dock, and 515 feet on the blocks, with a width of 74 feet 

 between the copings. The entrance is 50 feet wide, with a 

 depth of 20 feet over the sill. Advantage is taken of the great 

 rise and fall of tide to empty the dock by a culvert which 

 discharges into the river. 



For the storage of timber, there is a float of 10 acres, and 8 

 feet deep, on the west side of the dock, with which it is con- 

 nected by a canal. 



The extension of the Alexandra Dock consists of a basin of 

 27 acres area, with the same depth of water as in the Alexandra 

 Dock, and an entrance lock 503 feet 6 inches between the inner 

 and outer gates, this length being divided by intermediate gates 

 into chambers of 370 feet and 133 feet 6 inches long, with 36 

 feet of water over the outer sill at average springs. 



Queen's Dock, Glasgow. This dock (Fig. 14) is constructed on 

 the north side of the river Clyde, from the designs of Mr. J. Deas, 

 C.E. The dock is divided by a central tongue or jetty into three 

 basins, viz. the outer basin, 1000 feet long by 695 feet at its widest 

 part, and affording ample room for the largest class of ships to 

 turn ; the north basin, 1866 feet long by 270 feet wide ; and the 

 south basin, 1647 feet long by 230 feet wide. The width of the 

 quay between the north and south basins is 105 feet. The area 

 of the water space equals 33J acres, with a depth of 20 feet at 

 low-water spring tides. The quayage equals 27 J acres, and the 

 wharfage accommodation 3342 lineal yards. 



The entrance, which is a passage 100 feet wide, points down 

 the stream, and is so arranged that vessels entering are soon out 

 of the direct influence of the tide, and have a fair lead without 

 check to any of the three basins. 



