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TOURING the construction of
the Alexandra Dock at Hull, Mr. Abernethy was also acting as consulting
engineer to the new dock at Boston, the designs for which had been prepared
by Mr. W. H. Wheeler, M.I.C.E., who also superintended the work throughout.
The port, which is situated on the mouth of the river Witham, shortly before
it reaches the Wash on the east coast, was at one time one of the chief
places for the import and export of goods from Flanders and the Low
Countries. Large quantities of wine from the Rhine and Elbe for the use of
the monasteries, and merchandise from the Continent were delivered at Boston
and Lynn; while corn, wood, leather, and other goods were exported in
return. But from the fourteenth century it began to decline as a commercial
port, its trade being diverted to other places, though a considerable trade
remained till the increased draught of ships, difficulties of navigation,
and the want of floating accommodation, had nearly reduced it to the
condition of an inland town. In 1880 an Act of Parliament was obtained for
improving the outfall of the Witliam, which being obliged hitherto to find
its way to the Wash through a mass of shifting sands, afforded a very
imperfect discharge, and in times of heavy rainfall the lands were
constantly flooded. The Outfall Board was constituted of representatives
from the Witham Drainage and Black Sluice Tiust, the two principal drainage
sj-stems, and the Boston Harbour Commissioners. A new cut, about three miles
in length, was commenced from the point where the harbour authorities’
previous improvements in training the river had ceased, and extended into
deep water as advised in 1793, and subsequently by Mr, Rennie and Sir John
Hawkshaw. This cut is 130 feet wide at the bottom with slopes of 4½ to 1,
and has 27 feet of water at high water of ordinary spring tides, the width
of the top of the cutting, which is level with ordinary high water, being
300 feet.
This improvement of the
Witham, rendered feasible the construction of a dock at Boston, and from its
geographical position as the nearest port to the coalfields of
Nottinghamshire and Derbyshire on the one side, and the Continent on the
other, it is well situated for the export of coals, salt, machinery, etc.,
and the import of timber, grain, and agricultural produce, in return.
The Corporation of the town
in their capacity of Harbour Commissioners, obtained the Act to make the
dock in 1881, the money to be raised on the security of the harbour tolls
and borough revenue. In the House of Lords, the Bill was strongly opposed by
the Ocean Dock Company, who in the same Session were promoting a Bill for a
dock lower down the river, but the Boston Dock Bill passed, and work was
commenced in 1882. This consisted of a dock 825 feet long by 450 feet at the
widest end, the area being nearly seven acres; a lock 300 feet by 50 feet,
with two pairs of gates, the depth of water at the sill at ordinary spring
tides being 25 feet, excavation and dredging of the bank at its entrance, a
swing bridge 12b feet long across the river to connect the dock with the
goods yard of the Great Northern Railway, and two miles of line. The dock
walls are 32 feet 6 inches in height from the toe to the coping; 13 feet 6
inches thick at the base, and 6 feet at the top, having a batter on the face
of 1 in 4 for the first 10 feet above the floor, and 1 in 16 for the upper
part, and were constructed of concrete formed of 5 parts of burnt clay
ballast, 1 part of sand, 2 of sea shingle, 1 of Portland cement.
As the concrete was
deposited, rough blocks of concrete stone, as taken from the quarries near
Sleaford, were embedded, the quantity forming one-fourth of the whole mass,
no stone being allowed to be near the face or within 6 inches of another
stone. The foundations and braces of the lock were made of similar concrete
to that employed in the dock wails, out in the case of the lock, the walls
were faced throughout with Staffordshire blue bricks, the blocks of
brickwood for the facing being alternately, 1 foot 6 inches and 3 feet,
while the sill and hollow quoins were of Cornish granite. The dock gates
were built of pitch pine with green-heart heel mitre posts and bottom ribs,
each gate measuring 29 feet 6 inches in length, 32 feet in height, and 2
feet 7 inches in depth at the lowest part. Mr. C. D. W. Parker, C.E., was
resident engineer during the principal part of the time, when he obtained an
appointment at the Hull Docks, and was succeeded by Mr. R. J. Allen, C.E. |
