A contemporary report of a failed harbour development

From theislandwiki
Jump to: navigation, search
John Coode

This optimistic report on the largest development ever undertaken at St Helier Harbour was published in The Engineer on 23 February 1877. As the report indicates, the new pier had been damaged and a section washed away for the third winter in succession. At about the time the article was published the States took the decision to cut their losses and abandon the project, £160,000 already having been spent.

The plan to create a harbour for St Helier with deep water berths

Inadequate harbour

It will be remembered that, about nine or ten years ago, the legislative authorities of St Helier’s became aware that their harbour accommodation was quite inadequate to the requirements of this picturesque capital of Jersey, and indeed, the chief town of the Channel Islands. Not only was the daily Southampton mail packet frequently obliged to lad its mails and passengers in small boats, but the starting and arrivals of the Granville and St Malo steamers were necessarily fixed by the state of the tide; on account of the flatness of the shore and the numerous rocks with which the coast is studded, the navigation of the entrance to the port was a matter of considerable danger and difficulty. Premiums were accordingly offered for a comprehensive harbour scheme, and ultimately that submitted by Sir John Coode was selected as the best to put into practice, and was also rewarded with the first prize of £300.

Our engraving shows the plan of the works, as actually being carried out. The prevailing, and, indeed, the strongest winds blow from SW to WNW to counteract the effect of which it is proposed to make an extension on both sides of the natural breakwater formed by the reef on which stand Fort Elizabeth and Fort Charles, incorporating also the Hermitage Rock. From Fort Charles it is intended that the breakwater, named after it, shall proceed in a NE direction, for a distance of 550ft, and then take a turn to the ENE for another 350ft, being protected, where founded on the clay, by a granite apron. Between Fort Elizabeth and the Crow Rock a considerable area is levelled and appropriated to the workshops and yard, with a small pier for landing materials. The breakwater will proceed thence in a SSE direction for about 2500ft until the Platte Rock is reached, when it will take a turn to the ESE for another 170ft, terminating with a raised head provided with a lighthouse.

The approach to the landing pier starts from the Pointe de Pas just underneath the barracks of the Royal Engineers, and runs in a SSW direction for about 1600ft, when it is connected with the landingh pier by a curve of 200ft radius. The main portion of the landing pier is about 1500ft long, bearing nearly E and W, while the western end, about 300ft long, takes a turn to the WNW and is to be surmounted by a subsidiary light. It will be seen, on reference to the plan, that the breakwater overlaps the landing pier, and that the harbour is consequently protected from every wind that blows.

Pomp and ceremony for the laying of the foundation stone

Removal of rocks

The clear opening, forming the entrance to the harbour between the pier and breakwater, is 830ft, and the area of the new harbour is about 110 acres at low water. Ordinary spring tides rise and fall 32ft and neaps 14ft. Portions of the Grande and Petite Mangeuse rocks will be removed to low-water mark at ordinary spring tides, and the Petit Crapaud rock to 12ft below this datum, while the depth of water just inside the landing pier will be 18ft, and that along the Hermitage breakwater 20ft a low water during spring tides. The nature of the bottom is denite rock, alternating with patches of sand overlying clay; and trap dykes, more especially in the outlying rocks, have been met with.

The tide sets over the Bridge, as the natural causeway between Fort Charles and the mainland is called, at half tide, and will materially assist to fill the harbour, thus diminishing the strength of the current in and out of the entrance. The pier is to be provided with three landing stages, each on a different level, as well as with a landing slip and steps, served by a couple of 10-ton steam cranes, while a double line of tramway will run the whole length of the pier and its approach. The roadwaway of the pier is 55ft in width, and araised promenade, 17ft 6in wide, will be constructed on the sea side, protected by a parapet with weathered top to seaward and an iron railing on the harbour side; underneath the promenade will be ample space for storehouses, waiting and refreshment rooms, and various offices.

A crane used to move the giant concrete blocks

The height above high water, at ordinary spring tides, of the surface of the pier and breakwater is 8ft, and of the raised promenade, 22ft 9in. The total width of the landing pier is 72ft on the surface; the width of the approach is 52ft, and that of the breakwater 36ft. The latter throughout is one inch in a foot. The whole of the work is executed in concrete masonry, with the exception of the landings, steps and copings, which are of granite obtained in the island. The original scheme includes the turning of the present tiday harbour into a floating dock, and the formation of a graving dock.

Concrete construction

The Hermitage breakwater consists entirely of solid concrete masonry. While the work could be proceeded with at low water, the blocks were 10ft by 5ft by 3ft 9in, and weighed about 12 tons; but nhow that the foundations have been carried below low-water mark, a different method of working has been adopted. Large blocks of concrete, 22ft by 10 ft by 7ft, weighing 120 tons, are placed in position by a barge, and rest upon a bed of concrete deposited in bags of various sizes to suit the inequalitites of the rock. In some positions one tier of blocks is found sufficient to bring the work above low-water mark at spring tides, but in other cases two, or even three, tiers are required, according to the varying depth of water.

The blocks are laid throughout as headers, two blocks forming in width the foundation of the work. These large masses of concrete are made by hand upon the bed of the present tiday harbour, and are lifted from thence at high water, and conveyed to their position by a barge especially constructed for the purpose, provided with powerful lifting tackle. This method of forming the foundations dry within the existing harbour, and taking them out in large masses, generally lessens the amount of divers’ labour, which is works of this class isi not only attended with very great expense, but also limits to a considerable extent the progress that can be made.

1872 - the Hermitage is connected to Elizabeth Castle before work starts on the new breakwater beyond

At first the differences in level of the upper surfaces of the large foundation blocks were made good by a course of liquid concrete deposited in situ abover low-water mark, and the upper courses of concrete blocks act as ashlars, backed up, as the work proceeded, with large pieces of rubble stone and liquid concrete; but now the blocks are scabbled off to a uniform level, and the whole work is composed of solid blocks, which are set by means of a portable overhanging radiating machine, termed a ‘Hercules’, which has an overhang of 50ft, and will set blocks of 15 tons anywhere within that distance. This machine has been at work since May last, and has already set 200ft of the pier; and we hope before long to give an illustration of it with detailed description.

The steam ‘Goliaths’ employed for lifting the blocks in the yard have each 60ft span; they are constructed to lift blocks weighing 15 tons and this task they readily accomplish. The steam Hercules, steam Goliaths, 25-horsepower horizontal workshop engine, and a great deal of other work in connection with the plant, have been made in the most satisfactory manner by Stothert and Pitt, Newark Foundry, Bath; and the workshop machinery was supplied by Croft, Butterfield and Wilkinson, of Keighley.

The approach pier consists of two outer walls, the one on the harbour side being 5ft wide on the top, and that on the sea side being 6ft 6in; they are tied together with cross walls about every 35ft, and the pockets are filled in with a hearting of loose rubble. The blocks are 7ft 6in by 3ft 9in by sft 9in high.

Working arrangements

In the construction of the approach pier, while the foundations could be laid during the period of low water, the site was first cleared of all loose stones and mud down to the solid rock, when a bed of liquid concrete was laid on the spot and covered with bagging during one tide, to keep it from wash of the waves. When this bed of concrete had set, the blocks were run down on the temporary tramway, and laid in position with the aid of shear legs, with a conveniently arranged system of luffing tackle.

The joints were grouted with Portland cement mortar, and temporarily pointed with cement from Medina, in the Isle of Wight, merely to allow the Portland cement time to set. Above high-water mark at neap tides Portland cement was used once for all in the pointing. During the time that the foundations were uncovered at low water, all energies were directed to get as much work done as possible while the tide was out; and the superstructure and dry filling were proceeded with more leisurely as occasion served. But during the last working season, the advancement of this approach road was stopped until the breakwater shall have been carried out a sufficient distance to afford it some shelter.

The stone for mixing with the cement to form concrete, and also for the dry filling, is quarried from The Cut in the South Hill. The hot holes are bored by Le Gros and Silva’s Ingersoll rock drill, the tools or chisels of which were considerably improved at these works, so that it now bores rapidly through the hard sienite, which proved a severe trial to its powers at the outset. The drills are worked by steam, led in a flexible pipe from the boilers of portable engines. The debris from the quarry is brought down in trucks by a contractor’s locomotive to be arranged in moulds for forming the concrete blocks.

Here it is reduced to the required fineness by a Blake’s stone crusher, and then conducted to one of Ridley’s concrete mixers, made by Appleby, of the same pattern as that used on the Thames Embankment. An improvement has, however, been made by closing one end with a valve or door, after the charge has been received. The proportion is one part of Portland cement, supplied by the Wouldham Cement Company, and Peter Brothers, to two parts of good sharp sand from the shore, and six parts of broken stone.

The abandoned La Collette pier photographed in 1929

As much mixing is given by the machine as is required, and the charge is run out along a tramway laid over the moulds. These are of wood, the sides being jointed together. Core pieces are inserted in the sides for leaving holes whereby the blocks may be lifted by the lewis, and lalrge pieces of stone are inserted just above these cores for distributing the strain of lifting over a larger surface; other holes are also left for the dowels. The mould is filled up with a layer of stones alternately with the concrete.

The faces of the face-block moulds are seaped, for the purpose of allowing the blocks to strip more readily. A richer ‘compo’ is also put in for the face, but it is preferred to leave the other surfaces as rough as possible so as to take the grouting better. The blocks are left in the frames for 24 hours, after which time they are allowed three or four days more to set, but never longer than a fortnight. Ridley’s mortar mixer is used for mixing the cement of the joints; but an addition has been made of a tight-fitting cover with lever clutch. A mixture, made by this machine, of one part cement to four sand, is found to be more efficient than one cement to three sand mixed by hand.

A photograph by Ernest Baudoux of a storm battering the breakwater at La Collette

Three 'mishaps'

Since the commencement of the works in 1872 three mishaps have occurred, each in connection with the harbour wall of the approach road to the landing pier; the first was breach in the harbour wall about Christmas 1874; the second a similar breach very near the previous one, in November 1875; and the third occurred last November, also at nearly the same spot. The making good of the first breach cost £1,300; of the second £1,500; while the estimate for the third is £3,800; or in the aggregate, £6,600. These accidents are attrib utable to the same cuase in each case, the sea breaking over the unfinished work scooping out the hearting at the back of the wall, and wedging the wall loutwards from the pressure of water at the back and the shock from the waves. Had the work been completed it would have been impossible for eighter of these breaches to have been made, as the damaged wall would then have been within the shelterede harbopuring, no porition of the breakwater or exposed work which has been quite finished having suffered at any time in the slightest degree.

The estimated quantity of concrete block required on the works altogether is 250,000 cubic yards; and the amount of the first vote of the States Chamber for the works is £254,000. The breakwater is about 2700ft long from the starting point, and 1800 ft from the low water mark; the length of foundations laid to the end of December from the starting point is 1150ft.

The works are carried out under the entire direction of Sir John Coode, as engineer in chief, by Mr Imrie Bell, resident engineer. An assistant engineer, and accountant and about 350 men are regularly employed, the services of a contractor being entirely dispensed with.

Editor's footnote

This article shows how wrong most of the histories of the Harbour are. Several claim that work was abandoned in 1875 after one severe storm the previous winter, and Raoul Lempriere's 'History of the Channel Islands' says that work was abandoned in 1874 after storm damage the previous winter. Considering that the first winter storm was in 1874, Lempriere is way out.

George Balleine gets it right because he refers to storms in three successive winters - 1874, 1875 and 1876 before the work was abandoned, and quotes Acte des Etats of 31 January 1877 and 23 June 1877. This suggests that the States were getting nervous about carrying on in January 1877, perhaps as the Engineer article was going to press, but that a final decision was not taken until June, which would explain why the article suggests that all is going according to plan in February.

Leslie Sinel's Jersey Through the Centuries, which is a very valuable chronology of Jersey history, although poorly edited and sometimes inaccurate, is also misleading on the question of the harbour development. He records a gale on 8 December 1874 causing damage estimated at £15,000, further damage on 2 January 1875, and a decision by the States to bring the project to a halt on 11 February 1876, a full year before the article above was published.

Personal tools
other Channel Islands
contact and contributions

Please support theislandwiki.org with a donation to our hosting costs