28 LAUNCHING OF SHIPS IN RESTRICTED WATERS. 
it was necessary to dig a channel in front of the building slip about the length of the 
vessel each time before a launching. According to conditions, the vessel before coming 
to rest would bury herself about half a length in the mud at the end of the channel and 
_after lying over one tide was easily pulled out. This was a most harmless and effective 
method under ideal conditions and embodied all the elements essential to a proper solu- 
tion of the problem. 
Work must be performed to retard a vessel, and work is measured by the product 
of resistance into the distance through which its point of application is moved. Distance 
is equal to velocity into time, therefore time is an important factor in the retardation of a 
vessel. As the time during which a vessel is being retarded increases, the required re- 
sistance decreases. If a greater part of the distance available for retarding the Cali- 
fornia had been utilized as suggested by Lieut. Commander Saunders, less resistance 
would have been required, in which event the breaking of chains and cables might have 
been avoided. The snapping of chains or breaking of cables has little or no retarding 
effect on a vessel unless accompanied by substantial stretching so as to include an 
element of time during the breaking process. The method employed in retarding the 
California possessed in a high degree all the essentials necessary to accomplish the 
desired results. A similar method has been used for some time at the Bethlehem Harlan 
Plant, Wilmington, Del., but in lieu of wire cables 9-inch Manila hawsers are used. 
The frictional resistance or retarding force is effected by means of a wooden clamp. 
The climatic conditions in California are perhaps more favorable to launching than 
in the east, where it may be either excessively hot or cold, and on that account there is 
less liability of a vessel sticking on the ways. At the Bethlehem San Francisco Plant, 
where the pressure per square foot of ways was about the same as in the case of the Cali- 
fornia, a mean declivity of about 14 inch per foot at the start was usually adopted. It 
seems as though a mean declivity of § inch per foot, as used in the case of the Califor- 
nia, was excessive for such a heavy vessel, especially where the waters were restricted. 
Mr. R. WALTER CREUZBAUR, Associate:—As a civil engineer, who had been quite 
unfamiliar with some of the methods of launching ships in restricted waters, when I was 
put in charge of the civil engineering work at the Hog Island Shipyard and Bristol and 
Newark three years ago, the matter of outshore dredging, to provide sufficient run for 
the ships, was important and pressing. The dredges throughout the country were 
largely occupied, and in certain sections the prices on dredging were exorbitant. 
At Hog Island there were six and one-third million yards of dredging. It was laid 
out most generously and the question of the extent of the ship’s run after launchimg did 
not come up as a serious question, at least to the agent. At the Newark Bay Shipyard, 
at that time, with Admiral Rousseau I cut out a million yards of dredging on the assump- 
tion that three times the water-line length of the hull would be sufficient for the run of 
the ship from the end of the way. That restriction was much criticised, particularly by 
the people who thought they controlled the dredging prices. We got the War Depart- 
ment dredges in there and materially cut the cost of dredging for the work actually 
necessary. We did not dig that million yards of mud and it was never necessary; that 
is the point I wish to make. We were ready for launchings, and, though the declivity of 
the ways was somewhat too steep, in no case did the ships run far enough to give any 
trouble. Without any retarding arrangements and a 34-inch declivity three times the 
length of the hull was sufficient for the fairway. 
