The Sun.
London, England, 1862-03-10 00:00:00

THE NAVY.

Daring the recent debate in the House of Com-
mons on the Navy Estimates an interesting discus-
sion took place respecting the want of docks for the
reception of our largest class of iron ships, in which
Mr. Whitbread, Sir James Elphintone, Sir S. M.
Peto, and Mr. Corry took part. In this discussion
reference was made to the present depth of water on
the bar (so called, but erroneously) of Portsmouth
harbour channel; the dredging operations intended
to be resumed this year to increase its depth ; and
also the propriety of constructing a large steam
basin and docks in Portsmouth harbour. Sir James
Elphinstone stated that by dredging operations
Portsmouth harbour and its channel of entrance
could be rendered all that was desired, while Mr.
Corry, evidently well informed upon the matter,
more than confirmed Sir James Elphinstone's state-
ment, and spoke in the highest terms of the capabi

lities of the harbour. Mr. Whitbread, as a member
of the Board of Admiralty, made a cautious reply,
and promised a survey in April next which would
show the present condition of the harbour channel.
He feared that the construction of large docks and
basins inside Portsmouth harbour "might lessen the
scour by greatly detracting from the tidal water."
Although Mr. Corry's able statement was reassur-
ing respecting the capabilities of a port on which
we are spending, and have already spent, enormous
sums, Mr. Whitbread's official reply is calculated to
create an alarm upon the subject in the public mind,
for which, judging from the information in our pos-
session, there is no real foundation. With reference
to what really seems the most important point, the
depth of water in the shallowest part of the entrance
channel, the following return, compiled from official
sources, gives full information :—The depth of
water at the highest spring tides is 33 feet ; at ordi-
nary spring tides, say 12 per month, 30 feet; at
the lowest spring tides, 28 feet; at ordinary neap
tides, 26 feet 6 inches; at the lowest neap tides,
25 feet ; and at low water of the ordinary neap
tides, 22 feet. With respect to the filling in
of the harbour channel, we are assured
from the source from which we have derived
the preceding details that during a number of years
careful observations have been taken, more particu-
larly since the dredging of the channel by Messrs.
G. Smith and Co., of Pimlico, and that not an inch
of increase has been at any time found in the height
of the bed of the channel. This is corroborated also
by the evidence of the pilots of the port, Govern-
ment
and Trinity. Past surveys and observations
warrant the belief that the promised survey next
month will prove that the channel has maintained
the depth given to it by the dredging operations re-
ferred to, and that the depth will be further in-
creased by the aid of the sum already voted for the
purpose, which will render it, as Mr. Corry
observed, capable of affording a passage to the lar-
gest ships in the world. We have, however, pre-
viously protested against any dredging operations
being considered the best and most economical
method of improving the entrance channel of Ports-
mouth harbour. The means proposed to increase
the depth of water vary, no doubt ; but it is never-
theless a fact that all are agreed upon one important
point—viz., that the contraction of Portsmouth
harbour's mouth by the construction of defensive
works, in conjunction with the projeetion of private
works upon the bed of the channel in the immediate
vicinity of the defensive works alluded to, have so
deflected the water from its natural course in its
ebb from the harbour that it has wasted its strength
over the shoals intervening between the entrance
channel and Spithead, instead of concentrating the
force of its discharge along the bed of the entrance
channel, as it must have done had it been allowed
to retain the unimpeded mouth of exit from the
harbour, and entrance to the channel provided for
it by nature. The plans proposed to retain the ebb
in its proper course, in lieu of dredging, which
after a course of years may possibly have to be re-
peated, are too numerous to be noticed here. Two
of them, however, stand so prominently forward
that we cannot but advert to them. The first is
that . suggested by Mr. Pineo, C.E. He proposes
to enclose the shoals lying between the harbour
channel and Spithead with whole baulk cofferdam
piles, which would not only effectually confine the
ebb tide to its channel proper, but would also con-
vert the shoals into two immense basing for coaling
our men-of-war, and furnish on their sea face a con-
tinuous battery of immense strength, far more for-
midable to a foe than the proposed isolated marine
forts on the Noman, Horse, and Sturbridge Shoals.
Another remarkable feature of this plan is, that it
would extend the " walls" to Portsmouth to the
extent of the shoals further seaward, and therefore
virtually remove the dockyard to the same extent
further inland. If rifled guns of long range really
have anything to do with the position of our na-
tional dockyards, then this plan certainly deserves
serious consideration at the hands of the authori-
ties. The second plan is, as we have stated on a
previous occasion, the erection of a series of groynes
along the edge of the Hamilton Bank and Spit
Shoals, which form the south-west boundary of the
channel of the harbour, and which, it is contended,
would effectually confine the ebb in its natural
course. To us it certainly appears to be the most
simple and natural plan to remove the points of ob-
struction at the mouth of the harbour, restoring it
to its original size and form, when not only would
the ebb tide be relieved from the obstruction and

"deflection" it is now subject to as it seeks to rush
out through the narrowed mouth of the harbour,
but the flood tide would also equally benefit, by
being allowed to return to its natural course of en-
trance. There then remains but one other point
for consideration—Mr. Whitbread fears that the
construction of basins and docks at Portsmouth in
addition to those already existing " might lessen
the scour by greatly detracting from the tidal
water." This can be disposed of in a few words.
The construction of the proposed works on the
mudlands of Portsmouth harbour would, it is
asserted by those competent to judge, make about