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HARBOUR IMPROVEMENTS
SUGGESTED GRAVING DOCK.
[By our Special Reporter.]
Few other men in the colony have given
the subject of harbour improvements, and,
incidentally, graving docks, more study
than Mr. Hargravc, C.E., of Port Ade
laiac. au nis me has been intimately
associated with engineering works of this
nature in England and in the colonies, and
his opinions concerning tho suggested grav
ing dock for Port Adelaide are therefore
vorthy of consideration.
'A graving dock is absolutely necessary
or Port Adelaide,' he said, 'and lias been
for many years. The question has been
raised whether a dock will pay or not as
far as dock dues'arc concerned.' I do not
think it would pay the interwt on the
money and working expenses, at least for
some considerable period. Still, as a State
we should not take that matter into con
sideration. No port can be styled a first
lass port unless facilities are provided for
the accommodation of any ship which
might require docking and cleaning. The
benefit to be derived from providing facia
ties of this sort is not so much the dock
age fees and the payment directly from th-i
dock as from the indirect benefits for the
whole colony, for where facilities of that
description do not exist freights are higher,
and this militates against the welfare ol the
colony. Mr. Darley, Engineer of Harbours
in Sydney, in his evidence before the Grav
ing _ Dock Commission, expressed tbe
opinion that a dock gives prestige to a port,
klr. A. Wilson, Engineer of Ports and Har
bours of Victoria, also stated that 'with
out the Alfred Graving Dock Melbourne
would not be a first-lass seaport, and it'
Melbourne were not in a position to dock
vessels of large tonnage the trade of vessels
would not be secured. . . . There is
reat benefit given by a graving dock,
nsurance rates are much higher
or vessels trading to a port where
there is no docking accommodation,
and owners naturally avoid sending their
Vessels to a port where this facility does
not exist.' Mr. Wilson is quite right, and
on the grounds stated a dock is absolutely
necessary, if we are to hold our own with
the adjoining colonies. The position be
comes intensified under federation. If we
do not keep in line with the other colonies
South Australia, instead of being the first
place of call and Xhc last of departure, will
deteriorate into an outport. Any dry dock
constructed by the Government should be
available for all persons to tender for work.
That would tend to give the colony a good
name among shipowners, and artisans
would be enabled to contract for repairs
required, and dock dues would be the same
to all; therefore. South Australia would re
ceive a benefit in that direction.
'The question of site is important. A
graving dock would be of no service to
South. Australia unless it were capable of
locking the largest vessels visiting our
shores. The Alfred Graving Dock in Vic
toria is to be lengthened, and so are the
private docks of Messrs. Wright & Orr and
Duke's. Even then they cannot accom
modate the class of vessels which a dock
should be- provided for, because there is no
room in the River Yarra for them. The
Sutherland Dock, in Sydney, is also to be
lengthened. One of the principal things
in providing a dry dock is its accessibility.
If it is easy of access you reap the advan
tage. If not, ships .will pass by and go
where they can obtain the necessary facili
ties. Ihe most important aspect of the
whole question is what course the Govern
ment intend to adopt regarding tbe im
provement of the harbour. It is no use
laying down a dock unless it is a part of a
general scheme for harbour improvement.
Jecide what direction that will take, and
then it can be decided where the dock shall
be situated. Take our port as it exists at
present, and we will suppose that a 10,000
or 12,000 ton ship arrives here,
has broken her shaft, or met
?with some other accident, compelling
her to dock. Under existing conditions the
river demands that she must tow through
an intricate # channel at least eight miles
to reach a dock; or, if she finds the intrica
cies of the channel prohibitive, she must
steam or tow 600 miles along a dangerous
coast to obtain the necessary docking.
Now all these things militate against the
position South Australia should occupy.'
'Some mention has been made of a float
ing dock. Would such a construction
meet our requirements':'
'No. In the first place we have not
sufficient depth of water. We have here
within a reasonable reach a depth of 27 ft.
at low water. A floating dock on her bot
tom frame would mean 5 ft., and her sill,
equal to her blocking, would mean another
5 ft., making in all about 10 ft. We have
a rise and fall of about 8 ft., and 27 ft. at
low water means a maximum depth of 35
ft. Deduct her blocking and frame, and we
have only 25 ft. over the sill, which would
not afford sufficient accommodation for
large vessels. To obtain even that depth
dredging operations would have to be re
sorted to. Another objection to a floating
dock is that there are no means of effect
ing repairs unless at very much increased
rout. The work could not be done at the
IOCS Because Oi we lac*, ui Bpuvc, mm
large engineering works would consequently
be needed on shore. That is a bar to a
floating dock. In many quarters a wooden
dock has been proposed. This, however, is
merely a matter of expediency. Messrs.
Wright & Orr's and Duke's docks are both
constructed of timber, and are constantly
undergoing repair. If a dock is construc
ted it should be of either stone or concrete.
Private owners have adopted timber as a
matter of economy, but I scarcelylook up
on it myself as a true economy. Then with
regard to the dimensions. When Lord Ku
morcy was here in 189S I prepared a rcporl
for htm with respect to the length required
for a drv dock at the proposed outer har
bour at 'Largs Bay. What is necessary at
lirgs Bay is equally necessary at any other
site, so that the report may be quoted:—
1 append a tot of the docks in the colonies, with
their dimensions. You will see from the list
that there is only tbe Sutherland Dock, 60S It
by Si It, wilh a depth over the SOI of 82 ft.
at Ugh wster. capable of accoMnodatins; the
German Company's boats, four of which are from
613 ft to 533 ft in Itnffth. The above «Hm«n.
dons would. I think, meet the rwnimnents for
many year*, as there is a lwsth of 7S ft to
cover the increased length of ships which may in
tbe future rcouire docttn^ M necasary. by
working the outer stop, at provided at the Suther
land Dock, the length may be ^increased by SO
ftTgWng » totalS IBS ft. hetwern the taad
of dock and inner face of caisson. As ships
are likely to be increased in beam as wril «
I,n8th. it would perhaps be « w£j?JgT2S
forsuch - conitafwy. by gMns inereated with
to. ay ISO ft between the copum. The extra
&t rt widentar would b. PJfte^ *«» 'V. P£
ability of cramped space lor working, always
SS in mindPSa.t,lTltbough ,ǣ*ȣ'?
lMivthnwd at anv time without risk at reaso.i
abte eStTand wittiwttoterferiitfr with the utility
of ihVdoek. widcoinz would be espmhrc. ani
dutSE tlSTprogni^ the workthe dork . w«jM
be useless for any purpose connected with (hip
pl25{y estimates of the cost of «ch a dock
are as fouaws;- 33,252 cubic yards of ex
cavation. £7.38? !&.: 31,630 cubic yardu of
concrete! £4U1»; 2,600 cube feet of piles
and caps. £010; engineering, pump, and
SwhIs £5000: caisson, £4,000; blocking.
STOOO: Sriam^Twalls: £49,600; con
tinjtencies of enguneenn*. 10 per cent.,
£l£sK- 14s.; totaiT£mS97 2a. .Thwe are
rough estimates of the approximate cost
of a dry dock, -without wry other apph
ances than shown. In wtmatm* the cost
from finished working drawings fins wwld
probablr be found to be too loir, but I
should rjbmk £150,000 would be a saic esti
mate to fis.' ? ^___
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