The New York herald., 1870-02-13
TEE HERALD MARINE NEWS FLEET.

Description Of the Now Steamer Herald
'Meritorious Points of Construction.
[From the New York Times. Feb. 12.l
The new steamer Herald has certain principles In
troduced in her mouel which viii render an account
OF her dimensions and construction as well as the
results OF the trials, which took place
few days since, unusually interesting to
those familiar with the science OF naval
architecture The vessel was designed and
modelled by Isaac Newton. She was constructed
with the view OF attaining high speed under steam
without impairing the accommodations or sea-going
qualities.
The following the chief particulars and dlmen-
slons OF the hull and machlnery:-The hull is OF
wood, copper fastened; the plankng, inside
ceiling and keelsons are OF Georgia pine. The
length between perpendlculars Is 95 feet 2
inches; the breadth OF beam extreme Is 15 feet
1O1a inches and the depth OF hold amidships is
eight feet two inches. The general appearance OF
the vessel Is unusually symmetrical, and although
the lines are very fine, the weights are 80 skifully
adjusted IN relation to the displacement that not
only is steam machinery OF large power for che hull
easily carried but the cabin and other accommoda.
ttOns are unusually cOmmOdiOuB Tor steamer OF
this character.
The model was planned on the theory that the re-
sistance TO plane surface moving through fuid
Is IN proportion to the size OF the anglo which the
surface presents to the direction of notion and also
direction perpendicular to 1t. This OF course. doe
not take into account the frlctiOna reslstance
ness OF the immersed portion OF the null The engine
Is OF the form known AZ tue inverted cyllnder'
type. The cylinder Is nineteen inches in diameter
and the length OF the stroke seventeen inches.
The cranks and shafts are OF wrought iron, the
cranks bored and keyed on the shafts, the crank
pin being made Of cast steel. The valve gear con-
ssts OF o lnk'' movement constructed with certain
pecullarlties and with an Independent 'cuC On' ad-
Unstable at will while the engine is In motion The
condensation OF the steam Is effected BY surface
condenser, 80 arranged that the exhaust steam Is
condensed and pumped back again INTO the boiler
af IrA
water is circulated through this condenser By
means Of an independent pump. which
IA double acting the piston being nine inches IN
diameter and the stroke fifteen inches. The boiler
Is OF the horizontal tubular type, with the tubes
returning above the furnaces. 1t contains about
800 square feet Of heating surface IL Is constructed
pounds to the square inch. rne screw propeller has
four blades Its diameter is feet 10 inches aud the
terminal pitch III feet inches the angle formed by
the blades decreases nom tho AXIS to the circum-
ference IN the proportion which experiment
teaches Will produce cue maximum pr0pelling
efficiency.
On the trial a speed OF twelve knots, or nearly
fourteen statue niles, was easily maInta ned. THIS
speed was ascerrained by running over known dis.
tance. The numDer OF revolutions OF the screw was
seventy-our pounds per square inch and the cut-on
was adjusted that the mean pressure the piston
was furty-hve pounds Hence l35 horse power was
developed by the engine.
Now, ia order to form an accurate estimate or the
relative excellence OF the model, IL Is simply
Sary to compare the power exerted with the speed
attained ihis Is done by The ordinary rule, when
consists Of multiplying the area IN square feet. OF
the greatest immersed section py the cuDo OF the
speed. and dividing this amount by the horses
power the result Is number which gives
the relative excellence Of the model. AS ths
Immersed section OF the Herald Is sixty
square feet, the speed twelve knots and the
power l35 horses, the number Is 7e7. II is
believed that this Is the highest number on record
for vessel OF the Herald'S small Dimensions and 1t
proves the accuracy of the principles on which the
model was Designed But twelve kuoty 10 by no
means the maximum speed attainaole. This speed
was accomplished before the journals OF the engine
and screw had worn themselves TO proper bearing.
AS the boiler possesses ample steam generating
power TO maintain steam pressure OF at least
ninety pounds TO the square inch, with the 'cut on
at such point as TO keep up over seventy pounds
mean pressure on the piston. there can be no douo
that . speed OF considerably over thirteen knots
lnearly fifteen statute milesl can be kept up.
oclty rarely exceeded by the largest ocean
| The trials were witnessed by General Mcclellan
C. II. Delnmater. OF the Delamater Works; Messrs.
George Birkbeck, William Bromley. James Belknap
| q. H. Reynolds j. r. Robinson maripa cn.ineers
and other gentlemen interested In marine engineer.
| Tag sud shl3OululAG.