PACIFIC RAILWAY, PRINCE RUPERT, BRITISH COLUMBIA. 225 
assembled and shipped by water to Prince Rupert. ‘The erection of the 
first section is to be commenced as soon as the first three pontoons are 
launched, the compressed air machinery of the plant being used for pneu- 
matic riveting. 
PUMPING MACHINERY. 
The dock will be pumped by twenty-four (24) 12-inch centrifugal pumps, 
one in each end of each pontoon. By referring to Plates 112 and 114, the 
general arrangement and detailed construction of these pumps will be seen. 
The pump suction will take water from the bottom of the pontoon, the 
suction being protected by a liberal area of screen. Delivery will be directly 
through the flood-gate used in lowering the dock. 
The pumps will operate at approximately 275 revolutions per minute, 
being driven by a vertical shaft. All the pumps on each side of each section 
will be driven through gearing and horizontal shafting by one electric motor, 
as Shown in Plate 112. A jaw coupling is provided in the wing at about the 
level of the top of the pontoon for disconnecting the vertical shaft when the 
pontoon is removed for self-docking. 
There will also be seen in Plate 114 the indicator for determining the 
level of water in the wings. This consists of a counterweighted float in 
vertical guides and a vertical rod extending through the deck of the wing. 
As the water enters the wing the float rises and the height of the rod above 
the deck will indicate the depth of the water in the wings. 
A similar device, not shown, is provided to show the depth of the water 
in the pontoon. The flood-gates are operated to control the lowering of 
the dock and also to control the pumping collectively and individually of the 
different pumps, it being understood that with the pumps running, no 
water will be delivered if the flood-gates are entirely closed, and that, by a 
regulation of the gates without altering the speed of the pumps, any degree 
of control or any distribution of control can be accomplished. In case one 
side is rising too rapidly, the partial closing of the gate on that side, without 
disturbing the operation of the machinery, will effect the control, or the 
gates may be left at the same opening and the machinery stopped. 
By this method, a much quicker and more powerful control may be 
_ obtained, as not only will the discharge of water from the dock stop, but 
will immediately commence to enter, thus doubling the power of control 
which would be obtained by closing;the gates. 
