The Sun.
London, England, 1847-05-21 00:00:00

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INSTITUTION OF C1V147-EL:7-- -EN;
..,
GlNEERS.—Tur,spaiY.''''-':- -=._ , A
Sir JOHN RENNIE, President, illie Chat_ iv- (-7-- c;
The paper read was, "An Account ,of r . ~
Sands, and other iron vessels, with direct in
engines and screw-propellers," by John tiCi*;l4l 14
Liverpool, Assoc. Inst. C.E. The object the poper
was to show that a propeller might be constructed of
such dimensions that the number of revolutions it ve,tmill
require to make in order to obtain a high velocity woIN
not much exceed that of the ordinary paddle-wheel, an'd
that hence the usual marine condensing engine might be`
applied direct to the propeller-shaft a itlfout the inter-
vention of a secondary motion. It appeared from the
statements in the paper that this opinion was found to be
correct, and that " Woodcroft's" expanding pitch screw-
propeller was the best form that ha:i hitherto been em-
ployed. In a paper read to the institution upwards of
three years since, Mr. Grantham gave his views on this
subject, and several vessels tlacl been since built, the re-
sults of the trials of which Were communicated to the
meeting. The principal of these were the Emerald and
Diamond, three-masted steamers of 300 tons, anti
60-horse power; the Nautilus, of the same dimensiome
the Antelope, of 600 tons, and :100 power; and the Sarah
Sands, of 1,000 tons, and 180-horse power. Drawings
of these vessels were exhibited to the meeting. The
capabilities and performance of these vessels were
described in the paper, but particular notice was taken of
the last-named vessel, which had performed a most sue-
ecssful voyage to New York during bad weather and
adee?se winds. The passages made by the ordinary
New hark liners, which were out at the same time, were
very long, averaging 48 days each, and the Boston and
Liverpool r, earners were much longer than usual on their
passage. The* ,Sarah Sands used her steam about 17
days and sailed Ole remainder, making her voyage in 20
(lays 10 hours. Oat her arrival she had about enough
fuel remaining for tout days' steaming. The paper did
not enter minutely into Um tie niers of the screw itself, as
it was considered that too...n3ui:h attention had been given
to that branch of the subjeaat, 'to the exclusion of the con-
sideration of the plans for wc.'rking it, which, after all,
had been the stumbling-block •ta the general adoption of
the screw, the theory
ed;11
the system. It was necessary
of which as a propeller was so lit\ le understood, to pro-
ceed with experiments perseverhyly in one direction,
as variations in the results were frequently attributed to
causes Is hich really did not exist.. Alter describin
several interesting details, the paper Concluded by ex-
pressing a desire that engineers shouldexamine the
drawings of the system laid before the meeting, and
endeavour to add to the stock of information alt eedy
obtained. After the paper was read, Mr.. Gramthetu
added some facts which he had recently gathered, and
which strongly confirmed what had been stated. The
Diamond had recently made a very rapid passage to
Madeira, deeply lac:en ; but during the whole passa.,gh
the engines maintained a very moderate speed, :sad
quite removed the impression that under such circum-
stances they would run too fast from their being con-
nected directly to the screw. An account of the lam
successful voyage outwards of the Sarah Sands waA
also given, and it appeared that, in spite of most se-
vere gales, which had driven back almost all other
vessels, her passage had been made in the most satisfac-
tory manner.

I,‘
i

In the discussion which followed several engineers of
eminence expressed themselvee.much pleased with the
facts brought forward in the paper, and perfectly con-
curred with the views put forth. The principle of the
following current of the ship, which had a material in-
fluence in increasing the efficiency of the screw. was
alluded to, and a conviction was expressed that the screw
would eventually supersede all other means of propelling
vessels on long voyages. An account was given also of
the auxiliary screw-steamers that ply between London
and,liottt rdam, and some interesting facts were given of
the power which these vessels possessed of working to
windward in bad weather. The subject was closed by
discussion upon several points that had been started re-
lative to the size of the screw, the mode of disengaginc,
it, and the prospects which were held out of the tina
success of the principle.
The subject will be renewed at the next meeting, oni,
Tuesday, June 1, when the following paper will be►
read:—'• An account of the iron barque Josephine, of
Liverpool," by Captain Masters.
It was anneunced that there would not be any meeting
on Whit-Tuesday.