EXPLANATION OF TERMS USED 
has been entirely superseded by the term wet dock; a 
floating dock now signifies something very different, as 
will be seen below. 
A Dry Dock! is the converse of a Wet Dock, and in this 
country means a chamber, the floor and sides and one end 
of which are lined with watertight material, such as stone 
or concrete, and the other end provided with a pair of 
gates, caisson, or other means of closure, for the purpose of 
excluding the water during such time as the dock is occupied 
by a ship for the purpose of undergoing repairs. Such 
docks do not, of course, attain anything like the dimensions 
of wet docks, being constructed generally for the reception 
of a single ship, whereas wet docks and basins provide 
simultaneous accommodation for a great number of craft 
of all kinds. 
The dry dock is often referred to as a Graving Dock, the 
original word, ‘ graving” (engraving), being applied to 
the process of scraping, cleaning and painting, or tarring, 
the underside of a vessel's hull. But as much more 
extensive overhauls than this, and repairs of a very im- 
portant character, are carried out in dry docks, the latter 
term has come more generally into use than the other as 
indicating the wider range of service. 
A Floating Dock is, as the name implies, a dock structure 
able to float. It is generally constructed as a series of 
pontoons or chambers, which can be emptied of water so 
as to provide the necessary degree of flotation. Essentially, 
a floating dock consists of a floor or platform, with two 
side walls, all of steel framing and plating, upon and 
between which the ship is berthed. When the platform 
has been sunk to a sufficient depth to allow the vessel to 
float upon it, the pontoons are pumped out and the vessel 
1 In America, the term ““ Dry Dock ” is also understood to include 
the Floating Dock, described in the next section. Sometimes, then 
but not invariably, the qualification * Floating ”” is added. For 
the purpose of avoiding confusion, the author thinks it would be 
better to adhere to the clear distinction between the two structures 
which is drawn here. 
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