St. Paul daily globe. [volume] (Saint Paul, Minn.) 1884-1896, 1893-03-27
Bureau of Construction

received 10y the
Bureau OF Construction
from abroad show that France, Eng
land, Italy, Russia and Germany favor
ShtathiRg Of naval vessels and do so
extensively. That sheathing can be
successfully applied TO metal ship
while in The course OF construction is
demonstrated by the fact that a large
number of that class OF vessels, built
since lS65. are still III existence, and
have served in extended and repeated
commissions. The additional expense
incurred in putting on the sheathiHg Of
wood and copper is in reality great
saving during the life time Of the ship,
as it ObyiateS the necessity OF
frequent docking and the largely
increased coal bills when the metal
bottom is t0ul. For a vessel
like the Chicago the cost would be be-
tween S30J and 500 for docking alone.
To this sum mast be added about $1,000
for scraping and painting. In Great
Britain competition has brought the
charges Tor private docks down to a
minimum, but the docks in India,
China, Australia and on the Pacific
coast
Are Very Expensive.
Capt. Hichb0rn recommends that all
cruising vessels intended for genera! 4
service in foreign waters be sheathed OF
above 1850 tons displacement, and that
vessels OF less than 1000 tons diSplace-
ment intended for general service as
cruising guHbOatS, etc. be Of a COM
poSite construction, with steel FRAN
ing, wood outside, planking and cop
per sheathiug. An experienced engineer
of the navy makes the following state
ment: I'VE have seen from recent eX
IIy- 10 mr.
new cruisers are in the matter OF stay
ing away from port for long periods,
and ii is not too much to say that in the
event of q foreign war the navy of the
United States would be comparatively
VaIneless from the necessity or frequent
docking. Six months IS about the limit
of efficiency al sea for tile unSheathed
ship, and as this government has no
docking facilities abroad our ships must
cruise around our own coasts for the
proper cleaning which their unSneatled
bottoms must undergo. The periods for
which a shin with Il Sheatned bottom
may keep the sea without suffering any
elimination in efficiency is practically
unlimited, and in nearly every case the
cost Of the
Frequent Booking
of the unsheathed ship Will more than
offset the slightly greater cost OF the
sheathed construction. Briefly stated.
the advantages of the sheathed bottom
are: Complete protection Of the Wetted
surface or bottom of the ship from eX-
telior cOrrCSiOn, and, as consequence.
longer life fer the vessel: complete i'm
munitY from fOuliDg by marine
erOwths, either animal or vegetable, and
consequently 4 higher average speed
during cruise, or greater efficiency
as a cruiser. Following this latter con-
Sideration is the reduced amount of fuel
required TO cover distances at the same
speeds, being another addition to eff
cheney, eliminating the frequently re-
curing expenses for docking. Finally,
and resulting from the operation
OF previous considerations, is the
ability 10 keep the sea indefn-
iteiy with efficiency unimpaircd aud the
certainty Of being always ready for
service, near or Instant. The sheathed
bottom ship never needs to go in dock
Daring accidentS) during cruise, for
her bottom is in the same condition as
that OF wooden ship. The dls&dyan-
tagcs are: lncre ased first cost, in
creased displacement for ship CT given
dimensions. increased expenses of re-
pairs if the ship goes aground or is in
jured below the water line. The in
creased power required for a given
speed on account of the greater dis
placement is about offset Dy the de-
creased power required per square foot
OF WetGed surface on account of tine
smoother surface Of copper as COM
pared with iron or steel" Other prom
inenU officers Oh duly here speak in
favor Of sheathing, and are anxious 10
zee II tTled by our government.