The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1838-06-01 00:00:00

CORRESPOYDENCE.

TO THE EDITOR OF THE LIVERPOOL ST.,INDiIRD.

Stn.—l observed in f e Mail of .esterday another letter from
the individual who signs himself Z. I was glad to see that
letter, because it states the dimensions of the Sirius and Tiger
in detail. Z's " figures are satisfactory," as they enable me to
draw correct comparisons between the vessels whose characters
he advocates and the " Royal William." I will give figures
also, and thus enable the public to decide.

SIRIUS,

Length
Beam
Depth
Tonnage
Cylinders.
Stroke
Horses

181 feet 10 inches,
28 3
18 0
.696 tons.
60 inches.
6 feet 3 inches.
288.
TIGER.

Length 166 feet 6 inches.
Beaus . 28 0
Depth
Tonnage t.J 624 tons.
Cylinders 57 inches.
Stroke 6 feet.
Horses 256.
ROYAL WILLIAM.

Length
Beam.... .
•• 27 0
Depth
.. 16 9
Tonnage .617 tons.
Cylinders 6O inches.
Stroke
Horses .276.
By the above it is clear the Royal William has more power in
proportion to her tonnage than either of the other two; and how
it can be asserted that the Sirius is 320 horses' power I am at a
loss to understand. If Zbe ignorant of the mode olcalculating
the power of engines, he should have hesitated ere he attempted
to raise the characters of certain steamers to the prejudice of
others. If he be not, he wilfully tries to deceive the public. He
snag say that almost every engineer has his own method for cal-
culating power; perhaps it is so; but, in drawing the above
comparison, I' .have calculated on one and the same principle
fair all, giving the Sirius and Tiger a speed for their pistons of
2.10 feet per Miiinfe, and the Royal William of 231 feet.
As regards the detached boilers of the Royal William, the ~
ob-
servations Zarb really unique, I will ask, is it not desirable
that; in the event of one boiler receiving injury, others should
be available for working the machinery, if , not to theirfai/
power, certainly very near it, as has been already proved ?
Look at the advantages which three separate boilers ofi'er.
Suppose in crossing the Atlantic a steamer has a fair wind, she
can economize fuel to a great extent by putting out the fire of
two, as the steam generated by one will be quite sufficient to
turn the wheels round so as to preven,eir floats retarding the
velocity of the hull.
Z does not seem to understand the principles of working
steam economically, or lie would not say that a boiler larger
than necessary to generate for a given power is a waste of
fuel. Steam can be economised to almost any extent on board
the Royal William, by the aid of her expansive valves; conse-
quently, fuel can be economised equally by other means than
that of reducing the furnace surface. Z's comparison between
a house on fire and a vessel divided into compartments by iron
water-tight bulkheads is equally argumentative with the other
portions of his observations. He does not seem to know that
lire will cease to burn if deprived of air. Suppose any section
of a vessel so divided to be on fire; all that would be necessary
to extinguish it would be to close the hatches of that section,
and preventthe admission of air. In reply to Z's inquiry as to
where and when water-tight bulkheads have been proved to
prevent the foundering of vessels, I .beg to inform him that,
during the meeting of the British Association;in Liverpool, last
year, a steamer belonging to the City of Dublin Company,
having water-tight bulkheads, similar to the Royal William's,
had holes bored through the sides, on the wake of the lower
fore-hold, and that section thus filled to the level of the water
outside only depressed the vessel twelve inches. I will tell Z
that the bulkheads remained immovable and water-tight.-1
am, &c., AN ENGINEER.
P.S.—Z will observe that I have altered his figures as re-
gards the tonnage of the Tiger. According to the dimensions
he has put down, she is 624 tons, and no snore.