1 845. J 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



285 



we beg to refer for a full confirmation of our opinion of the necessity of 

 taking immeriiace measures for the preservation and im|)rovement of this 

 harbour. If this be not done soon, it is impossible to calculate on the ex- 

 tent of mischief which may take place, for in every south-vscst gale the Bea- 

 con Cliff is in peril of being washed into the sea. 



We therefore feel it to be our duty to submit to your Lordships the press- 

 ing necessity for carrying out a breakwater, or stone groyne, from the outside 

 of the Beacon Cliff, so as to surround tlie foot of it, and to extend the same 

 over the shoal-water, to the north part of the Cliff-foot rocks. 



We also recommend deepening the channel to the harbour to 18 feet at 

 low-water spring tides by removing the shoals called the " Altars," and the 

 eastern part of another shoal called the " Glutton." 

 Proposed Breakwaters, 



Having made such observations respecting the different ports as may be 

 necessary to enable your Lordships to form a judgment on the proposals we 

 have to submit, and having given to the subject referred to us all the atten- 

 tion which its importance demands, we recommend : — 



First, that a harbour be constructed in Dover Bay according to plan No. 

 1, Willi an area of 5'20 acres up to low-water mark, or 380 acres without the 

 two fathom edge ; with an entrance 700 fcet wide on the south front, and 

 aoolher of ISO feet at the east end. 



Entertaining the strong opinion we have expressed of the necessity of pro- 

 viding without delay a sheltered anchorage in Dover liay, we venture to urge 

 upon your Lordships' attention the advantage of immediately beginning the 

 work by carrying out that portion which is to commence at Cheesman's 

 Head. 



Whatever may be finally decided upon as to the form and extent of the 

 works in Dover Bay, the pier from Cheesman's Head, run out into seven 

 fathoms water, appears to be indispensable as a commencement, and it will 

 afford both facility and shelter to the works to be sulisequently carried on 

 for their completion. 



This will give sheltered access to the present harbour during south-west 

 gales, and protect it from the entrance of shingle from the westward : it will 

 afford time also for observation on the movement of the shingle within the 

 bay, and for further inquiry as to the tendency which harbours of large area 

 on this part of the coast may have to silt up. 



These inquiries the Commission consider to be of essential importance, and 

 the results will afford the means of determining on the greater or less width 

 that should be given to the entrances of the proposed harbour. 



Secondly, we propose that a breakwater be constructed in Seaford Road in 

 a depth of about seven fathoms water, one mile in extent, and sheltering an 

 area of .100 acres. 



Thirdly, that a breakwater be constructed in Portland Bay, to extend a 

 mile and a-quarter in a north-east direction, from near the northern point of 

 the island, in about seven fathoms water, having an opening of 150 feet at a 

 quarter of a mile from the shore, and sheltering an area of nearly 1200 acres. 



If only one work is to be undertaken at a time, we give the preference to 

 Dover ; next to Portland ; and, thirdly, Seaford. 



Mode of Construction. 

 Various plans for constructing breakwaters have been laid before us by 

 highly intelligent individuals, whose projects are noted in the Appendix, and 

 fully explained in the evidence. 



We are directed by your Lordships to report on the expense to be incurred 

 by the completion of the works we may recommend j hut as no approximate 

 estimate of this can be made without determining the general principles and 

 modes of construction, we have examined the engineers who have come be- 

 fore us, and other authorities, upon those important points. 



Their various opinions have been considered by the Commission, who pre- 

 fer, for the construction of breakwaters, and for the security of the works of 

 defence upon thrm, the erection of walls of masonry. 



The Commission do not offer any opinion as to the profile of degree of 

 slope necessary to ensure to the structure the requisite stability. They con- 

 •ider that this will be best decided by the Government, under professional 

 advice, when the works shall be finally determined on. 



The cost of either mode of construction having been stated to be nearly 

 the same, whether it be masonry, or a long slope of rough stone similar to 

 that of I'lymouth Breakwater, the Commission beg to lay before your Lord- 

 thips an approximate estimate of the works at the several places, viz. : — 



Dover X2,500,000 



Seaford 1,2.50,000 



Portland 500,000 



Harwich 50,000 



Protest. 

 This report was signed by nine only of the Commissioners, Captain Sir W. 

 Symonds entered a protest against it in the following terms : — • 



1 dissent from this report, because I consider the mass of evidence to be 

 in favour of Dungenos j and because I cannot recomincml a large close bar- 

 l)our at Dover, where the pilots consider the holding-ground generally indif- 

 ferent, and the engineers say it v.ill silt up. 

 Evidence. 

 Sir John Rennie's evidence. — (Chairman). The Commissioners have before 

 them a plan of yours for enclosing the small Downs. In the evidence you 

 gave before the Committee on Shipwrecks, you stated in answer to question 



59CG, that it will be four miles and half in length, but in your Report to the 

 Commissioners of Ramsgate Harbour, you say it will be live miles, "ill yo'i 

 have the goodness to explain how that is.' — The fact is, that in any work 

 constructed upon the Brake, the operation of accumulation, which I con- 

 sider will be produced by the works if conducted in a judicious and proper 

 manner, will be rather to rniseand increase the shoal in a particular position; 

 it may be a quarter of a mile, more or less, for it is difficult to state whether 

 it will be five miles or fuur and a half, till I know specifically the whole ex- 

 tent of the operations intended to be carried on. It is not like constructing 

 a mole out in the open sea, where the whole work must be done entirely 

 artificially; but here the object is to endeavour to make nature operate with 

 us in conjunction with art, so that it is a very difficult thing to say in the 

 first outset what would be the whole quantity which would be required to 

 be done. I have given, in the Report to the directors of Ramsgate Harbour, 

 an outside estimate, comprehending everything; but, I believe, provided the 

 work be carried on, only a portion of it will be required. 



You have alluded to the difllculties of constructing a breakwater at Dover, 

 are those engineering difliculties to which you allude.' — The difiicnities are 

 both engineering and geological, the principal geological ; the engineering 

 difficulties may be removed by a sum of money. I do not mean to say a 

 proper harbourmay not be constructed at Dover, but before 1 give an opinion 

 upon it, I should wish to have time to consider it, if the Commissioners wish 

 mc to turn my attention to it. In my Report I have alluded to the position 

 of Dover as a good position. The fact is, I have begun to consider it, and 

 have gone back to the early history of Dover Harbour. I have made a com- 

 mencement in the time of Henry VHI., and have got some very curious do- 

 cuments from the Cottonian Manuscripts, with drawings of all the different 

 changes connected with it; and the history is very cuiious. Originally, from 

 the facts we have, there was little or no mud in Dover Harbour, it was simply 

 a bay formed in the chalk strata, and a small river coming in there ; the 

 Dour discharged itself at times, v\hen it could, into the Channel ; but in con- 

 sequence of the prevalence of southerly and westerly winds, and the beach 

 driving from the westward, a shingle bank was formed in front of the mouth 

 of the river, so that the river, before it could get to the sea, was obliged to 

 expand itself into a large lake ; when this lake got sufficiently full from the 

 waters of the interior, and when the winds were not so strong without, it 

 burst through its barrier, and forced itself into the sea. Thus the shutting 

 and opening of this basin soon occasioned, on the one side by the winds and 

 waves from without, and on the other by the antagonist force of the waters 

 from within, and the basin formed what is called Dover Harbour. Strangers 

 looking at a position of that kinil supposed that nothing more was requisite 

 than to open the channel, and to confine it by works of art to preserve a 

 proper harbour, but in proportion as those works were constructed the beach 

 was increased, and the mud accumulated inside, and from hence has been 

 the advance and receding in Dover Harbour. 



Extract from the Evidence of 11 is Grace the D)the of Wellington, taken 



before the Select Committee on Shipwrecks. 

 "5264. Chairman. — The attention of the Committee has been directed 

 to tlie subject of a harbour of safety between Portsmouth and the Thames; 

 will your Grace have the goodness to state your opinion as to the necessity 

 for the erection of a new harbour .'" — ' I have no doubt about it. I entertain 

 no doubt that it is absolutely necessary. There is now no security between 

 Portsmouth and the Downs. Dover Roads is a very secure place, in the 

 period of a northerly or easterly wind ; but there is no security at other 

 times ; but, on the contrary, it is a very dangerous place in a wind from the 

 south-west. They can run for the Downs ; but there is no great ease in the 

 Downs ; certainly, there is no security in Dover, except from warlike at- 

 tempts. But I should say that, considering the want of protection from the 

 weather, and from military attacks in the Channel, the trade of the port of 

 London will be in a very precarious situation, and will be a very losing one, 

 in a variety of ways, in time of war, if something is not done beforehand — if 

 some precautions are not taken. Steam-power, in moving ships, has made 

 such progress at present, as that it must have a most material effect in mari- 

 time warfare (I use the word maritime warfare in contradistinction to naval 

 warfare) in all future times. If anybody will just consider the advantage the 

 French coast enjoys over the coast of this country, in observation of what is 

 passing at sea ; that is, to the southward, they have the sun in their backs ; 

 they see everything quite clear ; and it is possible, from the coast of France, 

 to calculate to a moment at what period a vessel coming up Channel will 

 arrive at particular points ; and they may he in readiness to seize her, at any 

 point which may happen to be unguarded, supposing the vessel to be with- 

 out convoy, and supposing tliat there should he no naval means at that point 

 to take care of her. I should say that the trade of the port of London would 

 labour under a great disadvantage if it were found that every vessel coming 

 up from Portsmouth was obliged to come up in a convoy ; that she should 

 be shut up unless there were a convoy; and there are no means of providing 

 for that safety except by ports ; not one only, but there ought to be, I >liould 

 say, nt least two between the Downs and Portsmouth. I should say one 

 about Dungeness, and another, possibly, nt Dover. I have given a goiul deal 

 of reflection to if, and liave thought of it a long while, and that is the con- 

 elusion to which 1 have cnnji- ; and it is a rational conclusion, for it is found- 

 ed on what the state nC the mirmerce of this port (which is the great port 

 of the country) will be, by-aml-hye, if something is not doue.' 



