58 



lohn Smeaton, the engineer chargeil with the construction of the magnificent Bui« 

 Ship Dock. 



December 9th. — After breakfast went with Mr. Smeaton and Mr. Blewa, the 

 local superintendent of construction, to examine the new dock and harbor. This 

 is perhaps the most extensive work, with the exception of the Duke of Bridge- 

 water's canal, ever undertaken and finished by one individual. This improve- 

 ment has been made by the Marquis of Bute, at his sole expense, at a cost of 

 nearly £:!00,000. The location was chosen by Mr. Telford, and the design and 

 execution were entrusted to Mr. Cubitt. It seems that the proper precautions, bow- 

 ever, were not taken effectually to secure the foundations for the massive lock, which, 

 in consequence of the pressure of the water, and the defect already mentioned, threat- 

 ened to give way. As the water had been drawn off, and the repairs were being 

 made, the whole of the forebay having been taken up, it afforded me a fair oppor- 

 tunity of examining it to advantage, and seeing its internal structure. Captain 

 Sniythe politely furnished me with the plans of the work, the map of the site, 

 and chart of the exterior harbor. This improvement comprises a ship canal 4,000 

 feet long and 200 feet wide, with massive quay walls on either side, coped with 

 blocks of chiselled granite. The canal or basin, for 1,500 feet in length, is calcu- 

 lated for 19 feet depth of water, 1,200 feet for 13 feet depth, and the remainder 

 shallows to 9 feet. The basin is supplied with water by a navigable feeder from the 

 Glamorganshire canal, or rather from the river Taaf. When it rises to 19 feet 

 above the mitre-sill of the forebay, it is wasted over a weir into a large artificial 

 pond, from whence the excess is discharged into the tide basin. This surplus wa- 

 ter serves to keep the tide basin free from silt ; by being admitted through a sluice 

 over a fall of nearly 20 feet at half ebb, its velocity removes the sediment which had 

 been deposited by the previous flood tide. The exit from the canal is through a 

 lock 156 feet long by 36 feet wide, (through which a ship of 1200 tons burden, 

 laden with timber, was passed the day the dock was opened,) into a tide basin, ca- 

 pable of holding 3,000 tons of shipping, shut in by a tide gate 45 feet wide, which 

 IB opened at 3^ hours' flood, when the tide outside rises to the height of the water 

 within, and vessels pass out to sea through a channel which has been excavated 

 m the mud, half a mile long and 150 feet wide, stretching from north to south; 

 and as the winds prevail in that direction, vessels are generally enabled to hoiat 

 •ail in the tide basin and put out directly to sea ; and in like manner they may 

 frequently sail into the basin without furling canvass or dropping anchor. Buoya 

 mark the channel on either side, by means of which vessels may warp in and out. 

 The masonry is all of the best granite, and built in the most solid manner ; all the 

 facings of the lock and ticie basin, and the copings throughout l>eing cut work, and 

 every portion of the structure exposed to the action of water being laid in hydrau- 

 lic mortar. The stone from which this lime is obtained belongs to the Lias, and 

 IS brought from Aberthan, in Glamorganshiie, and is found in rolled masses on 

 the beach, having been separated from the clay with which it u enveloped when 

 iri titu. It is burnt and stacked like fat lime, and is mixed m the proportion of 

 two lime and one sand. The other limes (the Dorking for instance) is mixed one 



