3i6 NOTES ON DOCK'S AND DOCK CONSTRUCTION. 



With these the divers were able to dress the macadam to a true 

 face. The foundation having been thus completed, guide-piles, 

 D (Fig. 313), were driven in pairs about 50 to 60 feet from 

 each end of the intended platform near the position in which 

 it had to rest. The platform, which was completely finished on 

 shore, was then launched, and floated down between the guide- 

 piles, DD (Fig. 313). 



"Both the guide-piles, D, and the guide-timbers, B, were 

 aligned from the shore without difficulty; but, in order to 

 obtain complete accuracy, corrected facing-pieces were fixed to 

 the guide-piles, and corresponding facings to the platform itself, 

 so as to bring it in absolute contact with its guides. Chains 

 were then attached to each side of the platform, carried over 

 sheaves, E (Fig. 313), at the top of the piles, and being brought 

 over to one side of the slipway, were connected together and 

 attached to a winch, F (Fig. 313), placed on a barge floating 

 alongside. 



"The scarf joints at the water-line junction were then placed 

 in position, and watched to see that they were not displaced 

 during the operation of sinking. Large stones or ballast were 

 then spread evenly over the surface of the platform until there 

 was sufficient weight to sink it, when it was carefully lowered 

 by the winch. In this way, any tendency of one side of the 

 platform to sink before the other was prevented, and the plat- 

 form placed in the position intended with certainty and 

 readiness." 



In preparing the foundation for a slipway at Earl's Ship- 

 building-yard, at Hull, to accommodate vessels from 2500 to 3000 

 tons dead weight, Mr. Godfery used whole-timber piles, cross- 

 sleepers, and longitudinal bearers 13 inches square throughout. 

 In the centre, two rows of piles were driven, 18 inches apart 

 from centre to centre transversely, and 3 feet centre to centre 

 longitudinally. For the side ways, single piles were driven 6 

 feet apart centre to centre ; these coming opposite every second 

 row of piles in the centre way. A sleeper 30 feet long 

 placed transversely on the four piles, and one 6 feet long on tin 1 

 two intermediate piles. Upon these sleepers were fixed tho 

 longitudinal timbers or rail-bearers, securely fixed with oak 

 treenails. The centre timbers were 4 feet 6 inches wide, to take 

 a plate of the same dimensions. The ground for 4 feet below 

 the cross-sleepers was excavated and filled in with rough chalk 



