The vessel or barge for carrying the machinery and pumps cost £600, and
the contract price of the machinery and pumps was £1,200. But before the
dredger was taken over by the company the alterations before enumerated
had cost about £300, bringing the total for barge and dredger up to
£2,100. In building a second dredger this might of course be greatly
reduced. The cost of repairs for one month's working has been only £5.
The contractor receives for labor alone 1-1/8d. per ton, being at the
rate of about 1¾d. for the dredging and 3/8d. for taking to sea--a lead
of two miles--all materials being supplied to him. The consumption of
coal is at the rate of about 1 ton for 1,000 tons of sand dredged. At
Lowestoft Harbor the total amount of dredging has been about 200,000
tons yearly, but this is now much reduced in consequence of the pier
extension recently constructed by the author, which now prevents the
sand and shingle from the sea blocking the mouth of the harbor. The
total cost of working has been 2.572d. per ton. which with 10 per cent
interest on capital, 0.240d., makes the total cost per ton 2.812d. The
repairs to steam tug, hopper, barges, and dredger have averaged about
2d. per ton.
Before the discussion on the paper commenced, Mr. Langley remarked that
attempts had been made to connect the engine direct to the pump of a
Bazin dredger, but this arrangement failed, and the belt acted as a
safety arrangement and prevented breakage by slipping when the pump was
choked in any way. A new lock was constructed near Lowestoft a short
time ago, and the dredger pump was used to empty it; when half empty the
men placed a net in front of the delivery pipe and caught a cartload of
fish, many of which where uninjured. In the discussion Mr. Wallick, who
had superintended the use of the dredger at Lowenstoft, gave some of his
experience there, and repeated the information and opinions given by Mr.
Langley in the paper.
Mr. Ball, London agent for M. Bazin, said that as devised by M. Bazin
the pump was placed below water level, so that the head of water outside
should be utilized; but he--Mr. Ball--now placed the pump considerably
above water level, as no specially formed craft was thus necessary. He
also described some of the steps by which he had arrived at the present
arrangements of the whole plant, and gave some particulars of its
working. Mr. Crampton asked some questions, in reply to which Mr. Ball
said the longest distance they had carried the material was 1,200 yards
in two relays--namely, a second pump on a floating barge with special
engine. The distance to which they could carry the material depended
upon its character. Fine sand would travel well; mud would not, bowlders
would not, though gravel would. To give the water a rotary motion he had
inserted a helical piece of angle iron, and so prevented deposition.
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