Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1915-03-26

In moderate deRths. ( III. ,sssestt siE..
Perhaps you will ASK why the mar.
gin of safatxt .Eepresented by the. re-
serve bIoyancy IL not increased when
these vessels are made ready for sub.
merged navigation? In return i ask.
IL you Lave ever tried TO swim under
server? IL so. you will appreciate the
fact that much Of your energy was re.
quired tosget youn body beneath the
surface, and that this left but little
power to drive you forward. A sub.
marine is composite vessel; she
must a5e able to run both on and below
the surface OF the sea. This has nat
uraIIy created difficulties in success
fHl pianning and, at best, any subma.
rine or submersible is a compromise.
Perhsps the most skilftii solutioi Of
this duplex problem Is that evolved by
the distinguished Italian engineer.
Mai. tsesare laurent He has given
his submersible q ship-shaped cutter
body which makes it possible to pro-.
vide his boat with an unusual measure
of bnoyancy when running on the sur
face and. incidentally, permits the hull
to he so formed that his boat can be
driven upon the sea &C high speed with
moderate engine power. In 4his. his
design differs. from the submarine.
which has less buoyaney in1tsurface
trim and. white capable OF higher.
speed under water. tiB not so seaworthy
nor 30 fast on sthe surface as the SUBJ
meFsi ole.i Inside the outer hull of the
Aaurenti beat DIS "a sturdy inner hull
capable s0f resisting water pressure
when deeply submerged Between this
strong fshell and the shipshaped struc9
ture - large air space (which fur
nishas the desired surface-g0ing hu0ys-
ancyIe The moment water aballast is
admitted to- the tanks IN the, lower
part Of the. dbost, the vessel settles
deeper into the seag andgthen by, open
ing certain ports orAdoofs in the su-.
perstructure the submersible sinks,
much deeper thus automatically sur.
rendering the greater part of her or.
binary factor of safety. Because nofs
this greater expsnse of superstructure.
however the sgbmersible is not capa.
BILE of travelling so fast as the sub
marine, for the, same power, under
water. These are the two forms that
modern underwater craft have follew.
ed. - = - -. = - - :.
As general rule the submarines in
the United States service are towed
on long trips and are invariably ac-
euTnpanied by another ship when VEN
turing for, any distance over the sea.
In striking contrast to this state of af-
fairs is the really extraordinary voy-
age fHf submersible built after the
design of Mi. laurent for the Swed-
ish government The Hvalen is a boat
OF only lS5 tons displacement, and
yet without an escort of any sort she
travelled practically 5000 miles from
the shipyaTd at Spezia, Italy, tGsS Stock
holm. During that journey she en-
eountered q good deal Of rough
weather, and yet she went steadily
onward. making her port of call like
any other seagoing craft of much
larger size. T. ... ..>c.s,* -.
= The French have done notable
things of late in keeping the sea and
in running long distances in their sub,
mersihles, but it must not.be forgotten.
that their boats range all the way
from 400 tons to nearly 1000 tons in
displacement The closest approach to
this character of vessel are the under.
water craft developed by Mr.. Simon
Lake. tho al, built by him for our
navy, yheing a fine. example of the