216 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



the dock is empty, six arterial box-drains are provided under 

 the floor. These are also connected with rubble drains running 

 behind the walls in the recesses, the whole being carried to the 

 drainage-well. 



For access to the bottom of the dock, and for the removal of 

 timber, four sets of masonry slides and slips are provided two 

 at the head and two at the stern ; whilst at the sides there are 

 four sets of steps or ladders 4 feet wide, formed in the double- 

 fender timbers fixed to the altars. 



