LAUNCHING OF SHIPS IN RESTRICTED WATERS. 25 
total of twelve. Although the probable launching weight of the new battleship is 
almost 50 per cent greater than that of the California, or about 20,000 tons, the 
necessary retarding effect is to be obtained by increasing the braking period, 
making use of the greater part of the channel fairway instead of attempting to 
stop the vessel in about 350 feet. Wire-connecting cables, secured to pad-eyes 
and lashed with small rope stops to the ship’s side, will replace the former chain 
cables laid down on the slip, and the friction cables will be laid out in pipes or boxes 
instead of being wound on reels. 
As a matter of fact, the unforeseen developments of the California launching 
were, in reality, the most valuable incidents that could have taken place. With 
the very high wind that was blowing across the fairway at the time of the launch 
it was indeed fortunate that the vessel stayed on the mud on the far side of the 
channel long enough for the fleet of tugs to make fast. Furthermore, the fact that 
the ship ran for about 250 feet with no other retarding effect than that of the 
water resistance has enabled the plotting of an accurate velocity-distance curve 
which would otherwise have been well-nigh hopeless of accomplishment. This 
curve, taken with the full-sized ship (cradle and all appendages in place), repre- 
sents accurately what the author has tried to obtain experimentally with innum- 
erable runs of the model. 
In connection with the above, and referring again to last year’s paper, 
Plate 13, it will be noted that the velocity of the model on Run No. 119, at 570 
feet travel, was exactly the same as that of the California at the corresponding 
point when the brakes were applied, 7. e., 21.5 feet per second. A solution of the 
two formulae (K,=VS and K,= ) for corresponding points in the free run of 
the model and ship, gives the following results :— 
Origin of curve from origin of velocity Model Ship 
distance curve, feet........ +27.2 —13.1 
Ty Are / 13,085 11,630 
TOUS eae 81.64 87.2 
The constant K, represents the number of feet that the ship would run in 
free route before the velocity were reduced to 1 foot per second. The constant 
K, is that employed in the equation R, =K,V* to obtain the approximate water 
resistance of the vessel at any given velocity. The constants obtained from the 
data of the California launch show that the ship had somewhat more resistance 
than the previous model runs would indicate, by about 634 per cent. The model 
cradle, however, in order to avoid undue complication and to permit easy and 
safe handling during the experiments, was not provided with the thousand and 
one minute appendages to be found on the larger vessel, such as wire rope frap- 
ping, spreaders, securing lines and wedges. Had the model been so fitted, it is 
considered that the water resistance would have been increased by fully 5 per 
cent, in which case the curves and constants obtained from ship and model runs 
would have been in remarkably close agreement. 
