THE RAISING OF THE DRY-DOCK DEWEY. 
By Nava, Constructor IL. S. Apams, U. S. N., MEMBER. 
[Read at the eighteenth general meeting of the Society of Naval Architects and Marine Engineers, held in 
New York, November 16 and 17, ror11.] 
The raising of the dry-dock Dewey which sank at Olongapo, Subig Bay, 
Philippine Islands, in May, 1910, was a wrecking operation somewhat out 
of the ordinary, and it is believed that a description of the methods employed 
and the difficulties and problems encountered in the work of raising will be 
of general interest to the Society. 
Although the dock has been described at length in several technical 
publications, a brief general description of the dock, and especially of its 
flooding and draining piping, will help to an intelligent understanding of 
the work of raising. 
Plate 64 shows a general outline plan and elevation. 
Plate 65 shows the arrangement of water tanks and their capacities, 
and the arrangement of the pumping and flooding piping, in the forward 
half of the dock. The after half is generally similar in arrangement to the 
forward half, except that it contains only one centrifugal pump. 
Plate 66 shows a cross-sectional view with some details of framing and 
machinery. 
Plate 67 shows the general arrangement of machinery on port side. 
Plate 68 shows the general arrangement of machinery on starboard side. 
Plate 69 shows a section on center line of pontoons and elevation of 
inside of port side wall. 
Plate 70 shows general arrangement of pontoon and side wall decks. 
The Dewey is a steel, floating, self-docking dry-dock, with a lifting 
capacity of about 20,000 tons, a length over-all of 501 feet, a clear width 
inside of the side walls of 100 feet; and it can be sunk so as to have 37 feet 
of water over 4-foot blocks and still have 4 feet of freeboard. ‘The self- 
docking feature was secured by building it in 3 sections, securely bolted 
together to form one structure when used as a dock, but entirely separate 
when self-docking. The main or middle section contains all of the boilers 
and main steam pumps, and other machinery. The machinery is all located 
on the port side, which is the side that sank, except one auxiliary boiler, some 
machine tools, etc., which are on the starboard side. The machinery is all 
