Autobiography of Sir John Rennie, F.R.S. 24

Autobiography of Sir John Rennie, F.R.S. 24

Meanwhile the defective state of drainage of the great level of the fens

still continued, and everybody was convinced that the only remedy was to

carry into effect the Eau Brink Cut as awarded by Captain Huddart. It was

therefore resolved that a new Act of Parliament should be obtained for

this purpose, increasing the tax upon the lands proposed to be benefited

sufficiently to cover the costs according to the estimate of my father,

who was appointed engineer-in-chief of the drainage interests; and the

above-mentioned gentlemen, Lord W. Bentinck, Sir A. Hammond, Sir Charles

Browne, and Thomas Hoseason, Esq., were appointed as the executive

committee.

 

The Act having passed, Messrs. Jolliffe and Banks tendered for, and

received and executed the contract.

 

The effect of this work greatly exceeded the most sanguine expectations

of its supporters. Immediately after it was opened the low-water mark at

the upper end of the cut fell five feet, and the drainage waters were

carried off with a degree of rapidity which astonished the whole country.

The autumn and winter of 1821-2 was characterized by an unusual quantity

of rainfall, and if it had not been for the opening of the Eau Brink

Cut the whole, or the greater part, of the level of the fens would have

been under water, and therefore the fenmen were very well pleased with

the result. At this time I was appointed to succeed my father as chief

drainage engineer, and the late Mr. Telford had been previously appointed

the chief engineer for navigation. Immediately after my appointment,

which was in the month of December, 1821, I went to Lynn to examine the

works, and was much astonished to find the great effects which had been

produced by the Eau Brink Cut. Instead of the circuitous old shallow

course, full of shoals and obstructions of every kind, there was a fine

straight, deep channel, two miles shorter than the old one, of the proper

width, bordered by strong banks of the full height; the floods passed off

without difficulty, and the navigation was so much improved that the

lighters and barges going up the river from Lynn saved several tides.

It is true that upon examining the country between Denver Sluice and

Cambridge, there was a great deal of water out in several places, but

this was attributed to the interior drains and rivers not being properly

defended and embanked, so that they could carry off the water to the main

outfall below. I also examined the new steam pumping apparatus, which had

lately been erected for draining Soham and other fens. This, although

proposed by my father in 1786, was the first of the kind that had been

erected. It consisted of a scoop wheel, with a perpendicular lift, worked

by a condensing engine. It answered its object completely, and has since

been imitated by numerous others with equal success in different parts

of the fen and lowland districts. Yet in many places it has been found

very difficult to induce the fen proprietors to combine together in order

to effect a natural drainage, which would be better and less expensive;

they prefer to act independently of each other, and adopt the steam

wheel. Still, even with this, the main outfalls must be improved to their

fullest extent, otherwise the water cannot run off; and when the floods

in the adjacent rivers rise so high that the banks are endangered, the

pumping must be discontinued, otherwise the banks will break, and then a

greater injury will ensue. Nevertheless, the steam pumping apparatus is

an immense improvement on the old windmill, which could only work when

there was wind.

 

My next appointment was to succeed my father as engineer-in-chief to

Ramsgate Harbour.

 

This harbour was established by special Act of Parliament for the purpose

of affording shelter to vessels of 300 tons lying in the Downs during

south-west gales. When these winds prevail that anchorage is crowded with

all classes of vessels, and the smaller ones, not being so well found

with ground tackle as the larger, are liable to be driven from their

moorings and fall foul of the larger vessels, causing them to go adrift

also, and thus creating considerable confusion and damage; but by having

Ramsgate under their lee, the small vessels can always get under way,

run for it at the commencement of the flood, and reach it in safety long

before high water, at which time the Goodwin Sands are covered, and a

heavy sea rolls into the Downs. In fact, Ramsgate Harbour was made for

clearing the Downs of small vessels, so that the large ones may ride in

safety, and so far has effectually answered its object.

 

There were a certain number of trustees appointed under the Act, who

were selected from the principal merchants and shipowners of London,

and the Deputy Master and three or four Elder Brethren of the Trinity

were members of the Board of Trustees _ex officio_. At the time I was

appointed engineer, the celebrated Sir William Curtis, Bart., member for

the City of London, was chairman, and the worthy Deputy Master of the

Trinity House, Sir John Woolmore, represented that Corporation with three

others of the Elder Brethren. As this was one of the oldest and most

important harbour trusts in the kingdom, I felt great honour in being

appointed their chief engineer, the more so as the celebrated Smeaton and

my father had previously occupied that position. It was here that Smeaton

followed out the idea that had been originally proposed at Dundee, of

establishing an inner basin with sluices for the purpose of scouring

away the mud which continually accumulated in the outer harbour, owing

to the great quantity of alluvial matter brought in from the adjacent

coast and waters, which otherwise in a very short time would have filled

it up and rendered it useless. Ramsgate Harbour was also celebrated for

being the first place of the kind where the diving bell was introduced by

Smeaton for the purpose of laying down moorings and removing obstacles

under water. The diving bell was afterwards, in 1813, much improved,

and rendered, for the first time, applicable to building masonry under

water with as much security and accuracy as building upon dry land. In

such an exposed situation it was more economical and expeditious than

the old cofferdams; it was in this manner Mr. Rennie rebuilt the east

pier-head in 17 feet at low-water spring tides, which was originally made

by Smeaton, and which failed. I also succeeded my father at Sunderland,

Donaghadee, Port Patrick, and Kingstown harbours, the West India Docks,

besides other places soon afterwards, so that I had a large business, and

was daily getting more.

 

The most difficult and anxious work, however, at that time was the

new dockyard at Sheerness, designed and partly carried into effect by

my father. He originally, in the year 1807, recommended that the old

dockyard, which was composed only of some old wooden slips imbedded in

the mud, a few storehouses, a wretched basin, lined with wooden walls,

and some timber jetties, should be abolished. He said that it was on the

lee or wrong side of the harbour, that the foundation for new works was

of mud and quicksand, that the space, on account of the buildings in the

old town, was very confined, and, therefore, that to make a good dockyard

there would be very expensive, and he thought it would be far better to

make a new complete establishment at Northfleet, just above Gravesend,

and to get rid of Woolwich, Deptford, and Sheerness altogether. Mr. Pitt,

then Prime Minister, decided that it should be done; but when he died the

matter fell to the ground, as I have before said, although the land was

bought for the purpose.

 

However, after the great war had terminated, in 1815, the nation was

naturally anxious to reduce the expenditure as much as possible, so that

the House of Commons would not listen to the idea of expending any large

sums upon great new works either for the navy or the army; and it was

only after considerable difficulty that the House of Commons would grant

money for the repairs of Sheerness Dockyard, and, like most extensive

repairs, it was found, when too late, that it would have been far better

to have abandoned Sheerness altogether.

 

Nevertheless it was absolutely necessary to do something to the Thames

and Medway dockyards, to keep in repair the large fleet of vessels which

was there laid up in ordinary. The total number of pennants flying at the

close of the war was about 1000, and the last vote for seamen in 1815

included 127,000 sailors and marines. As there was greater depth of water

at Sheerness than at any of the dockyards, and as the harbour immediately

contiguous was capable of accommodating with ease any number of large

vessels, Sheerness was decided upon as the place where the greatest

repairs and improvements should be made, and it ended in an entirely new

dockyard being built. The works accordingly commenced in 1815, and the

late Lord Melville laid the first stone at the north end that year. It

ended in expending nearly 3,000,000_l._, 1,700,000_l._ of which went to

the engineering department, and the remainder in the purchase of ground,

buildings in the town of Sheerness, in storehouses, mast and timber

ponds, smithery, admiral’s and officers’ houses. The engineering works

were of the most difficult kind; the foundations were composed of nothing

but soft mud and loose quicksands to an almost interminable depth, so

that my father was obliged to invent an entirely new system of hollow

walls faced with granite in front and brick behind. This system of walls,

which was entirely new, by giving a greater superficial area of bearing

surface with the same weight of materials, rendered them thoroughly

secure. He had adopted this kind of construction with perfect success at

the docks at Great Grimsby, in Lincolnshire, and they succeeded equally

well at Sheerness, although exposed to much greater difficulties. The

dockyard as completed consists of one basin of nearly 3 acres, at the

east end of which are three docks for first-rate vessels of war, with a

depth of 9 feet at low water of spring tides, the basin being of the same

depth, so that with a rise of tide of 18 feet at spring tides the largest

vessels can always be docked at those times. There is also another tidal

basin of about the same size, together with large storehouses, smithery,

mast ponds, boathouses, admiral’s and officers’ houses, chapel, &c., and

ample space for timber and other materials. This dockyard, therefore, as

was the intention, is well adapted for keeping in repair the numerous

vessels lying up in ordinary in the adjacent harbour, or for executing

any repairs which vessels on the northern stations may require; it never

was intended to be a building yard, and it answers its original purpose

well. It should be mentioned, that here Mr. Rennie first introduced

cast-iron gates for the dry docks; these fitted to the granite quoins so

nicely by polishing the two surfaces, iron and stone, with emery, that

they worked together perfectly, and were completely water-tight; and

although they have now been in use forty-five years, they are as good as

on the day when they were made.

 

At the time that these works were proceeding, it was decided to make a

new large granite dry dock at Chatham, similar to those at Sheerness; and

some improvements in the line of river wall, which partly interfered with

the free circulation of the tide there, were being constructed when I was

appointed, and I finished them.

 

The breakwater in Plymouth Sound, which was designed by my father and

commenced in 1815, had made considerable progress; in fact, the great

mass of rubble stone had been deposited throughout its entire length,

so that vessels of war as well as merchantmen could safely lie under

its protection during the heaviest gales from the westward. When I was

appointed engineer to the Admiralty, the late excellent Mr. Joseph