IN the Royal Dockyards these are constructed of masonry, the slope of the ?oor being about inch to a foot. At intervals of 5 feet to 6 feet down the slip balks of timber, termed land ties, are placed. These are of English oak 12 inches by 6 inches, their upper surface being ?ush with the ?oor of the slip, and are for the purpose of securing ways, keel blocks, shores, etc.