The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1855-10-30 00:00:00

BIRKENHEAD DOCKS.

The following report from Mr. J. Hartley, on the subleet
of the new works at the Birkenhead-docks, was read :

TO THE CHAIRMAN OF THE WORKS COMMITTEE.
Sin,—ln accordance with the resolution of your committee
of the 16th instant,. 'that the surveyor be instructed to pre-
pare a plan and report embracing the suggestions made at the
last meeting of the committee, when Messrs. Charles Mclver,
Hamilton, and John Laird attended, to afford information as
to the probable requirements of large class steamers, as
regards dimensions, length, breadth, draught of water, &c.'
I now beg to lay before you a• plan carrying out the sug-
gestions made by those gentlemen, so far as they related to
the construction of the proposed entrances to the great float
or pool,

a The principle of the design does- not differ from that of
plan No. 1, already submitted by me; The alteration consists
merely of the increase of the width of the large lock from 80
to 100 feet,. and in the recommendatien that its sill should be
laid at the depth of 12 feet instead of 10' feet below the level
of the old dock sill. It was also stated to be desirable that
the sill of the small lock should be laid deeper. I think if
this latter sill is laid at the depth of 8--feet below the datum
in place of 5-feet, as proposed, it will be as. deep as- can be
necessary for the- class of craft for which it" is designed. At
average spring tides vessels drawing under 6 feet of water
would be able to pass- over the sill after the first two hours
fibod tide, and at neap tides vessels of that draught might pass
in and out during the whole period of low water. The
practice with regard to craft bound upwards- towards Run-
corn, in tow of steamers, is to despatch them' about three
hours before high-water;- which enables them to arrive at they
shallow parts of the upper channel as soon as they have water
over them ; should they start earlier they would-have to wait
there. I may mention that the outer sill of the Deke's Dock
is four feet below the old dock sill, and I am informed by
Mr. Pendlebary, the manager there, that two feet additional
depth is all that he should under any circumstances -require
for the purposes of his trade; lam therefore led to believe
that the depth of 8 -feet, as now proposed, would be ample.
As regards coasting vessels- being able to get into dock after
two hours flood or spring tides, and at all periods- during
neaps,. would be an advantage -which has not been hitherto
afforded them,- and -would • enable them to be got in and out
prior to the time when the larger class of shipping would be
passing ; and it must be borne in mind, that at any time
when greater depths or earlier• access might be required, or on
occasions of large arrivals, these- vessels might be passed -
through the 50-feet lock, as -at that time it would be un-
occupied by the larger class of shipping.
"With respee to the suggestions of altering the width, of
the large lock to I 00• feet, and adding two feet to its proposed •
depth, I see no physical -difficulty is carrying it into effect.
The hindrance to- laying the sills -of wide entrances at the -
depth proposed arises not only, as-I before stated, from the -
trouble of keepinee_the platforms of, gates clear of sands.
which increases with the area of the platform, but there is also
the danger of not heing able to maintain a. proportionate depth,
in the outer basim. In proposing to lay the flooring of the-
outer basin 17 feet below the old ajek!-sill, I have had this-
danger in view, and have allowed a considerable margin of)
depth below that at- which I proposed, to lay the large sill, so.
that in case the sluicing power propo^„ed to be adopted should
not effectually maintain the full depth, there should be still at
all events as much water-, under any circumstances, there as
upon the sills. So far as- regards the- approach to the 50-feet
entrance., I see no impediment to its maintenance which may
not be overcome, as the channel thereto will be along the
south wall, and within the efficient action. of the sluices ; the
edmepbtarhrassmaimnteanintsedinbymad
obstruction, if it exists) will be in the centre of and near the
entrance of the basin, .at• the greatest distance- from the power
of the sluicing water. This -may also be removed, and the
expected that if we lay the sills at theseincreased depths, our
manner augmented, and that hindrances-will' arise that must
be anticipated and borne:with.
mdginintainigngertioltehirereinainrea.y; but it must be
" I am,.sir, yours very respeetfullw.:ll,
"Jorm Be HARTLEY.
be in like

"Dockyard, 19th October, 1855."
Some desultory conversation followed, in. the course of
which:the Chairman intimated that he wished to state it was
the opinion of Mr. GAS that the Fla at should be left in a
state of nature, and that docks should be made.upon each side
of it.