The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1901-09-29

is called the citadel, which rises like
an oblong box out Of the center of the
snip. This citadel is armored with six
inches of plate. These boats will be
furnished with three engines working
three screws, and capable of generating
3,OOO-horse power apiece and able to drive
the ship at a speed of twenty-five knots
per hour. Steam will be supplied by six
boilers of the Mosher type and to work
under a pressure of about 800 pounds.
The main feature is that under ordinary
conditions they will float on a normal
water line, giving them a free beard of
about seven feet. When it is desired
to go into action they will be submerged
by letting water into ballast tanks III
the bottom of the ship, which will then
float with a freeboard of only three feet,
leaving only the citadel above water
The efficiency of the boat will not be
affected should shot pass through this
citadel
"A remarkable specimen of the submar-
inc. boat is the Porpoise which was
launched at Nixon's shipyard yesterday
afternoon at the same time as the tor
pedo boat Nicholson. The Porpoise is the
third of five submarine boats ordered by
the government, and the Nicholson is
sister ship to the O'Brien now build
ng, 1t had been arranged to launch
both boats last Thursday, but the death
of the president made a. postponement
necessary.
The Porpoise is 60 feet long. Her mid
ship section is that of circle II feet in
diameter; from the midship section. tho
boat gradually tapers both ways. At the
center of the boat is placed the coming
tower. which is made of armor plate four
inches thick, and from which the move
ments of the ship are controlled The
top of this tower is made so that it can
be opened and closed. Through this
opening the crew pass in and out of the
boat There is also a superstructure
which serves as a working platform upon
Which the crew can stand when the
beat is running on the surface of the
water. The only armament carried is az
torpedo tube placed forward, from which
a fullTsized Whitehead torpedo can be
discharged under water
| The boat is propelled when she Is on
the surface by a 16O-horse power gas en-
fsg1nei giving her a speed of eight knots
an hour, and when submerged by sew
enty-horse-poWer motor, which gets it's
| current from storage batteries in the
middle of the ship and under the floor
| of what constitutes the living room The
rest of the machinery consists of a biIge
| pump used for diScharging any water
Which may enter the boat, an air com,
| pressor to fill the storage tanks with
compressed air, which is used to operate
the auxiliary machinery, such as the
steering and driving engine, an oil pump.
and small engine forward used to raise
the lower cap placed over the end of the
| torpedo tube.
+ :, The gas engine is directly connected to
the main shaft by means of friction
clutch, and the motor is also connected
to the main shaft by gear wheels and a
friction clutch on the after end of the
motor; the forward end of the motor is
connected by gear wheels. and a clutch to
the gas engine, so that when the ship is
running on the surface the gas engine
will drive and at the same time, if need
ed, will run the motor converting it into
a dynamo, which is then used to charge
the storage batteries.
Owing to the limited amount of air