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  • Writer's picturePaul Whittle


The most probable inventor of Portland cement was Joseph Aspdin, a Leeds bricklayer, whose obtaining of patent number BP 5022 for ‘a super cement supporting Portland stone being…..An improvement in the Modes of Producing an artificial stone’ was recorded in the Leeds Mercury on 6th November, 1824. Little appears to have been done to develop Portland stone until Joseph’s son William entered into an agreement with a firm of Roman cement manufactures, Maude, Son & Co of Rotherhithe in East London to make the Aspdin cement. There is no suggestion that the son made any innovations to his father’s process. At this time work was underway on the building of the new Houses of Parliament following the 1834 fire and in 1843 the contractors carried out tests to compare Maude’s (Aspdin’s) new cement with the available Roman cement. The results of the tests seem definitively to show that the new cement was almost twice as strong as the finest Roman cements available. Sixty years earlier John Smeaton called the cement he used to build the third Eddystone lighthouse “Portland cement” because of its resemblance to Portland stone but the evidence is far more compelling that Joseph Aspdin’s 1824 product was indeed the first true Portland cement.

The importation of Portland cement to North America started in the late 1860’s and was only viable because ships crossing to load grain and cotton cargoes could carry cement as ballast free of charge.

The development of maintenance or ‘capital’ dredgers for such tasks as channel clearing and land reclamation progressed separately from that of that of the aggregate dredger by way of all manner of craft such as the water harrow, mud mill, scrapper dredger, grab dredger, & bucket dredger. The first hydraulic (suction) dredger using a centrifugal pump for dredging spoil was thought to have been that invented by the M. Bazin in 1864 and it is this dredging method which was eventually adopted by the City of York for aggregate dredging.

The City of York

A paper published in the Scientific American of 1882 records…A new lock was constructed near Lowestoft a short time ago, and the [Bazin] 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…perhaps understandably, commercial suction dredging for fish did not follow from this event!

In the mid 1800’s the Hampshire coast was also dredged for cement stones by cargo & fishing vessels, which alternated between trades as recorded at The Southampton Archives Services, to wit:-

In the 1800’s Milford-on-Sea’s trade “.. was supplemented, to a degree by smuggling and dredging septaria from the bay for cement making

Friends Good Will: Built 1840. 12 tons “….1887 Coastal trade; 1888-90 Dredging cement stone at Barton Cliff, transported to I.O.W."

Sailing vessel John and William: Built 1846 at Oulton, Kent. 24 tons. “….1873-80 Fishing; 1889 Coastal; 1890 Dredging for cement stone at Barton Cliff, Hurst Castle.” It is interesting to note that at the time that one “Arthur Payne of the Gunn Inn, Keyhaven” was the registered owner of the John and William, the seasonal Keyhaven salt trade “…was supplemented, to a degree, by smuggling and dredging septaria from the bay for cement making…”

Liberty. Built 1855. 10 tons. Registered Southampton. Owner T. Bright of Yarmouth I.O.W. “…1869 Fishing and dredging….”.

Sailing vessel Maid of Kent. Built 1848 at Milton, Kent. 18tons. “..1877 Fishing and stone dredging….. 1882 Laid up and dredging for cement stone….

Sailing vessel Mary. Built 1844 at East Cowes. 21 tons. “…1891 January to June dredging in Christchurch Bay; July to December oyster and sprat fishing in the Solent……1897 to 1899 Dredging in Lymington”

MARY discharging cement-stone alongside West Medina Cement Mill at Dodnor on the Isle of Wight where the septaria was turned into Medina Cement.

(Alan Dinnis provided the above photograph of the Mary and writes that his grandfather was the manager of the West Medina Cement Mill which ceased production in 1944 when it became a depot for importing cement from the mainland. The mill ruins were cleared away a few years ago to become the Vestas wind turbine factory with just a few kilns remaining as an industrial archaeology site. Read more about the history of the mill in Alan's book

"West Medina Cement Mill" ISBN 9 80950 4126343.)

Also in 1862, H.W.Bristow’s The Geology of the Isle of Wight. Memoirs of the Geological Survey of England and Wales, comments:- Cement stones are obtained to a small extent from Alum Bay, but the greatest supply is now derived from the opposite coast of Hampshire, where the septaria, which once formed a portion of the Barton beds, are procured by dredging

The method of dredging used by these vessels is not known, be it spoon and bag, an adapted fishing trawl, cockle scoop or some other system devised specifically for stone dredging.?

In the early days of ballast dredging the rights and profits from the trade belonged to the Lord High Admiral of England but, in 1594, the privilege was transferred by Lord Howard to Trinity House and which for many years was their principle source of income. In the river Thames, an act of Elizabeth 1st’s reign gave the Corporation exclusive rights to supply dredged ballast to vessels in the River Thames from London Bridge to the sea. The trade not only provided a useful income but also helped to keep down the river’s shoals. Trinity House kept full rights until 1853 when the money realised from ballast was allotted to the Mercantile Marine Fund. Trinity House craft were the chief ballast dredgers until the Thames Conservancy, later the Port of London Authority (P.L.A.), took over the trade.

Ballast was needed in vast quantities by sailing colliers around the UK’s coast and such projects as the construction of the London Docks which used thousands of tons of dredged material. In the mid 1800s colliers in Blyth and other North East Coast ports discharged ballast by antiquated horse cranes before going to their loading berths. Nothing was paid for gravel dredged from the Thames and it was unpopular with ships’ crews who preferred to work with chalk ballast as it could be sold in the Tyne. Brigs going north to load at Blyth used to discharge as much ballast as possible at sea before entering port as there were penalties for throwing ballast into the river. In later years the P.L.A. supplied contractors with most of the ballast it dredged which was carried by a fleet of battered old craft between the dredgers in Lower Hope and ships alongside wharves at Greenwich, Leigh, Southend and elsewhere.

The removal of sand for ballasting ships was sometimes less than welcome as exampled by the notice given “To Owners & Masters of Vessels” on 16th November 1863 by the Manor & Royalty of Kenton which threatened legal action against any found removing sand from “The Warren, Warren Sands, Ridge or Pole Sands” in Devon’s River Exe.

Dredging for Thames ballast finally stopped on 31st March 1951 because the seams of suitable material on the bed of the Thames estuary were running out. A report at the time confirmed that good ballast still exists in the river but only in areas which cannot be worked by large dredgers without inconvenience to port traffic. It was also believed that extensive dredging “..may be affecting land on the banks…”

The world wide use of sand for ships’ ballast gave rise to the importing and exporting of all manner of local flora such as the report which claimed “…so much ballast was coming into port, as in the case of Liverpool, it was often used to build the foundation for new roads …hence plants from Asia, Africa & the Americas can still be found sprouting from cracks in undeveloped niches in the city…”. It is also reported that a number of buildings in some of the American East Coast ports used UK sand ballast in their concrete mix.

The use of sand for ballasting ships was generally for the duration of a voyage, stone or other materials being used for the permanent ballast many ships carried to keep them stable. Sand ballast needed to be properly managed on board as, whilst it increased the stability of a ship, it could also contribute to its untimely end, as was the case in 1880 with the 886 ton sailing ship Transit . With 60 tons of permanent stone ballast and 352 tons of sandstone ballast “of which the master stated was more sand than stone” on board the Transit sailed from Liverpool for Quebec on 26th September. After leaving port, the ballast was cleared away from around the pump casings. On October 14th the ship’s log reported “SW gale with hard squalls” and by noon she was “under lower top sails, labouring and straining heavily and making a great deal of water” requiring the crew to be kept continually at the pumps. By noon on the 15th the pumps were chocked with sand ballast and the crew were reduced to “bailing by bucket & tub”. At 0415hrs on October 24th with the crew “bailing all night” the Transitstruck the beach of Prince Edward’s Island”. “The crew all landed safely and the Transit rapidly filled and broke up and was eventually sold for $450”.

The subsequent Board of Trade enquiry “did not consider that it (the sand ballast) was proper and safe ballast, insomuch as a large portion of it consisted of sand, and with so much sand it should have been protected by matting or otherwise (i.e. loaded in sacks) . For this transgression, together with a number of others relating to the navigation of his ship, the Board of Trade suspended the master’s certificate for three months

The River Orwell’s River Commission established was established in 1800 and plans were drawn up to deepen the Orwell which resulted in the purchase of a dredger which “…. in 1920 made a cut though the Round Ooze. Making it unnecessary for vessels to use the circuitous and difficult channels by John’s Ness …the following year they made a further cut to take ships straight across the bank between Hog Island Reach and Limelink Reach.” The sand removed was sold “for ballast or for building” and the money raised used to pay off the loan raised to do the work. “By 1830 The River Commissioners had paid off the original loan of £8000 and had accumulated a surplus of £25,000, which went towards financing the building of the wet dock”

For centuries small wooden sailing ships came to the river Wear for coal, glass and pottery and as they arrived on the tide and moored up, they would be served by the keels which were flat-bottomed craft carrying a variety of buckets, skips and slings. The ship’s crews and keelmen would unload the tons of sand ballast from far-away beaches. As each keel was filled it made its way to the bank where the sand would be dumped on dry land.

In the 19th Century the sand requirements of the glassworks in Smethwick were very largely met by the particularly pure / suitable Belgium sand which came as ballast in returning ships employed in the export of British goods.

Another report, from the River Tyne, records that visiting ships arriving in ballast deposited their ballast which “commonly contained flint and Cornish clay which could be used by local potteries” and which “buried any archaeological remains to a considerable depth.”

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