138 A 1,650 HORSE-POWER GASOLINE FIRE BOAT. 
other wooden frame giving a 24-inch spacing, these angle frames extended down 30 inches 
into the wood hull and were bolted both to the frame alongside and to the outer planking. 
The %4-inch steel side plates extended 6 feet beyond the bulkhead at each end and were 
fastened down by lag screws every 6 inches through a 2%-inch by 24-inch bounding angle. 
The deck beams were 6-inch channels with 2-inch by 2-inch brace angles instead of gus- 
sets. Deck plating 3/16-inch finishing at sides and ends with 2¥%-inch by 2)%4-inch cover 
angles. 
The pilot house at the forward end is all steel of a little lighter scantling. This gave a 
machinery space 50 feet long, the full width of the hull. The after 20 feet of this was taken 
up by the propelling machinery and auxiliaries, the arrangement of which was left undisturbed 
save by the removal of the center 220-horse-power “Standard” engine, together with its 
shaft, wheel and rudder. 
In the forward 30 feet there are installed four 8-inch three-stage De Laval centrifugal 
fire pumps, each directly connected to a 300-horse-power “G. R. C.” type Sterling eight- 
cylinder motor. These pumps are right and left and are arranged two on each side with 
a working gangway 30 inches wide between. The pumps are in the center and take their 
suction from a 10-inch fore and aft suction main between them. This main is fed by four 
10-inch seacocks, two at each end, each with its stop valve and a 24-inch washout connec- 
tion from the discharge main between the stop valve and out-board strainer. The suction 
main has two flexible diaphragm joints to take up any working of the hull. The pump suc- 
tions connect through 8-inch standard ells and gate valves to 8-inch by 10-inch standard 
crosses in the suction main. By this arrangement all the pumps can draw from any one of 
more, or all the seacocks. As the boat may have to operate in shallow muddy slips the con- 
sequent danger of stoppage from choked seacocks is thus practically eliminated. 
The discharge connections are on the outboard side of the pumps and connect to the 10- 
inch central overhead discharge main through 8-inch by 6-inch reducing ells, 6-inch swing 
check valves, 6-inch copper bends and 6-inch stop valve. 
Owing to the sharp dead rise of the hull it was not practical to set the pumps low 
enough to prime completely by gravity, and a Nash “Hytor” exhauster, driven by an elec- 
tric motor, creates a vacuum system which primes the pumps almost instantly. 
The outlets from the discharge main consist of two 8-inch risers forward and aft, each 
with a six-valve turret head surmounted by a 2,500-gallon “Invincible” monitor nozzle, and 
a 6-inch riser to the top of the pilot house with a similar nozzle. 
All valves and fittings throughout the suction and discharge systems are regular manu- 
facturers’ standard and extra heavy patterns, except the sea chests and turret heads. 
Both suction and discharge mains have a central stop valve allowing forward and after 
sections to be operated independently. 
Since there are in the 50 feet by 14 feet machinery space forty-six gasoline motor cylin- 
ders aggregating 1,650 horse-power, the question of ventilation is of prime importance. 
This is provided for by two 2,000-cubic-foot-per-minute electric blowers, taking air through 
the after end of the steel trunk house and delivering it through ducts abreast of each pro- 
pelling and pump engine. 5 
To remove the hot air there is a 26-inch electric ventilating fan in the 42-inch ventila- 
tor stack. In addition there are two 5-inch electric exhausters, taking air from the bilges 
of the engine and gasoline tank rooms. There are also sixteen 14-inch air ports in the sides 
of machinery space. 
