Daily press. [volume] (Newport News, Va.) 1896-current, 1899-10-19
NOTES OF SHIPPING.


-
4'he most detailed investigation OF the
scs5los of speed. horse power and coal
consumption that has been made is at
So'''ucted by Sir John DurStOn Of the
Stean engineering department of the
brltish navy. His experiments were
conducted with the second-class cruiser
Hilahflyer, recently completed at Glas-
;SoN. 1t was ascertainetl that a horse
kSwer Of 2.135 was sufficient to drive
S'ls shlp at q speed OF II 1-2 knots an
nour. But 1t required 1914 horse pow er
70 crlve her at the speed of 1914 knots
10 get an increase of 55 per cent. in
speed required an increase Of 2S5 per
cent. in power. The speed was then N
creased to POI knots, and this cost an
Studltlonal 200 horsepower or a GOOD
ueai more than the power to drive the
snip the first II 1-2 knots AT each of
cnese Speeds the ship was driven for
elSht hours SO that the test was fairly
rouplete
me consumption of coal did not rise
so hast as the horse power. The con-
sumption ct coal per unit Of power was
TESS at the high speed than at the lower
rates But this does not altar the fact
tnat Il little extra speed costs (, great
deal OF fuel. AT - - knots the High
1iycr burned ".43S pounds Of coal per
nour. and it required $3.50 pounds per
7our merely to increase the speed tie
last Z of Il knot from 1914 to POI knots
Inc loss resulting from the fo9mati n
OIL smoke is absolute for it is euuiva-
cent to directly robbing the fire cc a
part OF the fuel from which not cn,v
mas no heating effect been secured, hut
upon which heat has actually been
wasted in raising it 10 the temperature
or the escaping tluc gases Fortunate
~. from q purely economic standpoint.
Ems loss seldom. if ever exceeds one
per cent. of the total ca.orinc value Of
she fuel. In fact the prevention 81
smoke is not to be considered s., much
IN us economic aspect as in it's relation
to the stringent laws Which are being
. enforced IN many communities 1t
thus becomes q question OF life +
"e2th. Tor unless the smoke is prevented
/ 'the boilers cannot be operated For.
Vhe prevention of smoke. sharp intense
hTalt Is necessary. properly regulated:
and capable of furnishing the required
amount OF air, both :bclrw and above
she coal at the Very cmcnt M'ncn it S
most needed
This result can be lest secured by lie
introduction of the mechanical draft
Whrsh is ordinarily SO regulated from
Shc opening of the fire doors the charc-
ahS OF the furnace, or the cleaning Of
the fires. instantly causes an increase in
me speed Of the fan and the intensity
OF the draft ana the volume Of air. The
inherent ability of mechanical ,lrafr rs
maintain IL high furnace pressure CO.
operates 70 make the dis targe -
smoke almost impossible. In addition,
the positivcness of the draft makes
~ H., =
or understanding device if it be found
Sirable.-Exchange
\ foreign engineer sums up the ad
Tantages and disadvantages of two
well known types of water tube boil
e1's as follows: The Bellcville ty,.e is
wei! adlpt1i for maintaining high GOA
tlnunus sea speeds for long periods
ana is Very economical at high pow ers
1t is comparatively light ard we'll ar
ranged for cleaning ana overhaul nc
Steam san be raised quickly, and large
variations in power made readily 1t
cannot. however, be forced. and has
also The objection Of great complication
OF detail and accessories, with ccnsc-
uuent liability to arrangement The
1;irrGW type is hardly so Well adapted
Tor continuous stcaminS az relative h gh
powers, and is not so economical en-
ccpt when tittc11 With the feed -i,eatin..
arrangement recently devised BY A. T.
1arrcW. 1t can. however, be forced to
almost any extent With safety and
much higher speeds obtained Tor con-
siderable periods. Steam can be raised
quickly. and large variations in power
l,;'lc readily. 1t is extremely light and
being simple in detail. has small labil-
ltN OF arrangement: cleaning and ever
haul are fairly easy but the examina-
ton OF the outside of the tubes is diff
fcult. The cylindrical tyne is about
equal to the Narrow for continuous
hlSh-poWer steaminG. though probably
slightly less economical, At low DOW
ers, however. ii is very economical 1t
T can be moderately forced with safety
and is we'll adapted for ordinary clean
ing and overhaul All its ARRANGEMENT
are extremely simple and unlikely to
become deransed. Sea water can be
used in it with safety. 1t is however
heavy; steam can only be raised very
slowly; and large variations in power
cannot be made quickly"
NO contracts for eNorb;iant salvage
are binding. This rule mover changes
When the regular wreckrg boats un-
dertake TO save a ship {. contrast is US
uaiiy made beforehand, and this is less
likely to he q contract under compul-
sion because there are several COMMA
MES To bargin with, but not long ago
the ship Jcssamene ran on the rocks