EXAMPLES OF DOCK PLANS. 17 



high-water mark. The length of wall available for wharfage, 

 omitting the entrances to docks and lock, is about 13,800 

 feet. 



The lock connecting the tidal basin with the main dock is 

 700 feet long by 80 feet wide, and is closed by wrought-iron 

 gates. It is divided by intermediate gates into two chambers, 

 one being 555 feet and the other 145 feet in length ; the object 

 of this arrangement being the saving of water in docking and 

 undocking. 



Parallel with the lock, there are two dry docks 875 feet long ; 

 one has a top width of 70 feet by a total depth of 35 feet, with 

 32 feet of water over the sill at ordinary spring tides ; whilst 

 the other has a width of 60 feet by a total depth of 30 feet, with 

 27 feet of water over the sill at ordinary spring tides. These 

 docks have entrances, closed by floating caissons, to both the 

 tidal basin and the main dock, therefore either can be used as 

 an entrance lock in case of necessity. Each dock is divided by 

 an intermediate caisson into two unequal lengths, so that there 

 are practically four docks available for repairing purposes. 



The entrance to the tidal basin is about at right angles to 

 the river. It is trumpet-shaped, and is formed by running out 

 timber jetties, heading up and down stream. 



Bute Docks, Cardiff. 1 The Roath Dock (Fig. 10), constructed 

 from the designs of the late Mr. J. McConnochie, M.I.C.E., is 

 situated on the south shore. The length of the dock is 2400 

 feet by a width of 600 feet, equal to an area of approximately 

 35 acres. The available wharfage, allowing for entrance and the 

 width occupied by ships at the side walls, is about 5700 feet, 

 with a depth of water of 38 feet 8 inches. The dock is entered 

 through the Roath Basin, to which it is connected by a lock 600 

 feet long by 80 feet wide, with a total depth of 43 feet 6 inches. 

 The depth of water over the sill at high water of ordinary 

 spring tides being 35 feet 8 inches, and at neap tides 25 feet 

 8 inches. The lock is divided by intermediate gates into two 

 chambers. 



The Roath Basin (Fig. 10), which forms the outer entrance 

 to the Roath Dock, is 1000 feet long by 550 feet wide, equal to 

 an area of 12 acres ; the available wharfage is 2700 feet. 



The entrance lock communicating with the harbour is 350 

 feet long by 80 feet wide, with a depth of water over the sill 



1 Engineering, vol. xxxviii. p. 135. 



