Carlingford Lough and Greenore.” Byjanles BARTON, M

CARLINGFORD LOUGH Ah’D GREENORE. 131 February 8, 1876. GEORGE ROBERT STEPHENSON, President, in the Chair. KO.1,435.-“ Carlingford Lough and Greenore.” ByJAnlEs BARTON, M. Inst. C.E. THEAuthor proposes in this Paper to give an account of some improvements effected in the Lough of Carlingford on the east coast of Ire.land, during the past few years. This Lough, shown upon the accompanying map (Plate 4), lies about halfway between Dublin Bay and Belfast Lough. It is sheltered by a natural rock barrierextending fromHaulbowline Lighthouse to Ballagan Point, on the south side of the entrance. This barrier is uncovered almost throughout at low water of spring tides, and part of it is above high water. The entrance to the Lough isconfined to a deep- water channel between the Haulbowline Lighthouse and the Scars whichextend from the SoldiersPoint. The natural entrance, 3 fathoms deep, is about 700 feet wide. Outside this, however, there is a bar-a tail of Cranfield Poinhf blue clay and boulders, which extends across the entrance from the north side in a south- westdirection, and upon which there was formerlya depth of 7+ feet of water atlow tide.South-west of this shoalthere exists a channel more than 18 feet deep throughout ; it was dis- covered by the late Commander Hoskyn, Superintendent of Charts at the Admiralty, who surveyed the Lough, and laid down the channel in 1857 for the first time, and it is called the Hoskyn Channel. Commander Hoskyngave evidence,as tothe great natural capabilities of Carlingford Lough as a harbour, bothbefore the Royal Commissions and the ParliamentaryCommittees who have since dealt with questions relating toit. This deep-water channel, he stated, might,if properly buoyed and lighted, suit steamers; but having two turns at right angles, it could not suit other vessels, and further experience has shown that it would be dangerous even for steamers in rough weather. Within the Lough there is a large area of deep water, safe for anchorage in all weathers, and with good holding ground; the extent for anchorage over 18 feet deep at low water of spring tides is about 1,200 acres. For above one hundred years the navigation from Carlingford Downloaded by [ University of Melbourne] on [22/09/16]. Copyright © ICE Publishing, allB2 rights reserved. 132 MINUTES OF PROCEEDINGS. Lough up to the town of Newry has been the subject of much engineering thought. Reports were made by Mr. Kimmo and Sir John Rennie, and a ship canal and lock were constructed under the latter ; but the bar was not thenconsidered with a view to its. removal. In the year 1845 the Commission upon Tidal Harbours took evidence upon the subject of cutting a channel through the bar from Mr. John Ramsay, who had made some borings and examined it. The Commissioners reported that : “ To render this Bay avail- able as a harbour of refuge, the bar should be deepened to at least 18 feet at low water spring tides, and this for a breadth of two cables’ length, or 400 yards ; the loose boulder-stones should all be, picked up, the limestone skirts of Haulbowline Island should be. removed, and the Earl and otherrocks blasted away. The estimate for deepening the bar was &50,000, but even if double that sum were required, it would be well bestowed in accomplishing that which could not fail to prove an invaluable boon to the numerous vessels navigating the Irish Sea, and, as such, is justly entitled to be considered an object of national importance.”’ In the year 1859 the Commissioners on Harbours of Refuge re- commended the improvement of twelve harbours, of which two were in Ireland, Carlingford and Waterford ; and of Carlingford theyreported: Lough Carlingford, on the east coast, offers 8 spacious natural harbour in the very position that a Life harboul- in this districtwould be desirable, namely, in the track of Liver- pool vessels bound through the North Channel, and of ships from the Clyde bound south through the Irishsea:’’z The Government brought in and passed, in the following years, the Piers and Harbours Act of 1861 and 1862, by which harbour works were facilitated and loans provided, by the Harbours and. Passing-tolls Act, 1861. Under these Acts one of the first applica- tions was made, by the advice of the Author, in the autumnof 1862 to the Board of Trade by the directors of the Newry Navigation Company. They asked for powers to cut the bar of Carlingford,. and to form a channel through it 600 feet wide and 21 feet deep. at low water, at zi cost, including the removal of some rocks, of ;E100,000; and it was proposed to levy ratesupon all vessels enter- ing theLough to pay the interest and instalmentsof a loan for the- - Vide Tidal Harbours Commission. Second Report of the Commissioners, Appendix, p. 63a. London, 1846. * Vide Report of the Commissioners on Harbours of Refuge, vol. i., p xi. London, 1859. Downloaded by [ University of Melbourne] on [22/09/16]. Copyright © ICE Publishing, all rights reserved. CARLINGFORD LOUGH AM, GREENORE. 133 purpose. Severe opposition arose, and the project was abandoned for thatyear. In the year 1863, however, some gentlemen interested in the Irish North-Western railway,in concert with other local interests, kook up the project, and applied for a provisional order for cutting the bar. This was passed in 1864; and in 1366 a loan of 3230,000 was made by the PublicWorks Loan Commission upon the security of the rates, after an investigation and reportupon the project by Sir John Coode, M. Inst. C.E. The exposed position in which this work had to be done, and the difficult material of which the bar is composed, rendered the cost of theoperation somewhat exceptional;and though the prices were very different from that for ordinary dredging, they were probably as low as thework could be carried outfor, and lower con- siderably than the only tender obtained from contractors. The sea upon the barof Carlingford was too rough for dredging when there was any windfrom the southern half of the compass, and if it blew heavily from the southward the water was too rough for two or three days afterwards; hence the time for work was very limited, and a special dredgerhad to be designed. The dredger was so constructedthat it could lie safely at anchoron thebar in a sea in which dredging could not be continued, and thus be ready waiting for opportanities of working ; it was self-propelling, having a pair of twin screws. Thedays in each yearduring which dredging could proceed varied from sixty-seven in 1871 to one hundred and thirty-one days in1873, and upon many of these days the work was limited to one or two hours. The tonnage raised in .one season varied from 50,060 to 99,720. Arrangements were made to work every quiet hour in summer, and incalm weather the same set of men were employed, sometimes for two or three weeks, from sixteen to nineteen hours a day. The best result was obtained by giving each man a bonus in money, according to his position, for every 1,000 tons of material raised in the fortnight, in addition to his standing wages. The material consisted for the most part of plastic blue clay, occasionally free of all stone and fine enough for pottery work, but generally with bouldcrs of limestone, greenstone, or granite imbedded, and these varying from shingle up tostones of 4 tons weight. The dredger was designed to excavate in a depth of 37 feet of water ; and practically, operations were often carried on at a depth of 34 feet to 35 feet ; the depth of channel excavated being 18 feet at low water, and the rise at high water of spring tides being 16 feet and 17 feet. The dredger was constructed by Messrs. Simons Downloaded by [ University of Melbourne] on [22/09/16]. Copyright © ICE Publishing, all rights reserved. 134 MINUTES OF PROCEEDINGS. and Co. of Renfrew, and was of such a model as to steam itself between the Clyde and Carlingford without a tug. The engines are of 60 nominal HP. The mode of proceeding was byarc- dredging ; the dredger, beingheld by six anchors and two backing anchors, was mpved in her work by six steam winches, capable of reversing instantly, and working throughgrooved friction-wheels. The buckets are large, and have strong steel lips with projections to give an entrance into the hard material. The bucket girders are of wroughtiron, 90 feet longby 43 fect deep;the sides. are plated with lattice bracing at the top and the bottom; the hoistinggear is frictional,and the tumbler bars are of steel, With careful handling the dredger will take out any stones imbedded in the clay, and lift in thebuckets all stones of 30 cwt. and under ; those over that weight, when cut out by thebuckets, were thrown off by the arms carrying thelower tumbler, andwere, as occasion offered, chained bya diver and raised on the deck by a crane- constructed on the vessel's bow for that purpose. The average amountraised per day when any work wasdone by the dredger was about 850 tons; but in the ordinary blue clay and stones of thebar about 150 tonsper hour was theusual quantity,and 1,200 to 1,500 tonsper day. On thenorth side of the bar a bed of gravel lay for some distance in the hollows in the clay; in this the d'redger has on different occasions taken up over 3,000 tons in a day, and on one occasion over 4,000 tons in a day of about sixteen working hours.

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