42 Report S.A.A. Advancement of Science. 



This view was greatly opposed by some of those in authority, 

 who considered that an extension of the North Pier would merely 

 drive the bar further out to sea beyond the reach of the dredgers. 

 It was a point absolutely vital to the success of the Durban Harbour 

 works, and therefore to the Colony. Its gravity was such that I 

 felt bound to fight for my views to the utmost extent in my power, 

 though at the time I did so unsuccessfully. 



My views were subsequently submitted to and confirmed by 

 independent engineers, and a year or two afterwards, the Govern- 

 ment extended the northern work to its present position and destroyed 

 the overlap, and dredging was carried on under the favourable con- 

 ditions which I had so strongly advocated. That is, the scour induced 

 and trained by the extension of the North Pier, was brought to bear 

 in assisting and maintaining the work of the dredgers. The result 

 has been that the average depth at low water on the bar for last year 

 was 30 feet, or 36 feet at spring-tide high water, and the largest mail 

 steamers now enter and leave the harbour in perfect safety. 



Prior to the extension of the North Pier, there is no doubt what- 

 ever that the natural tidal scour and the dreiging were largely 

 opposed to each other, and the liability of the bar to the sudden 

 shoalings which frequently took place during very short spells of bad 

 weather, sometimes lasting not more than from 24 to 48 hours, 

 reduced the depth much below the loaded draught of the dredgers, 

 and made it impossible to work these effectively, or with any hope 

 that their work would be maintained. 



My view of dredging was expressed in a report to the Natal 

 Harbour Board, in 1892, as follows: — "If the North Pier is not 

 extended, the only course will be to tax the revenue of the Port 

 for all time, in order to keep it open as far as possible by dredging, 

 an expedient which will not only be a millstone for ever round the 

 neck of the port, handicapping it severely in the face of competi- 

 tion with other ports, such as East London and Delagoa Bay, but 

 will only be temporary and intermittent in its effects according to 

 weather, while it will certainly fail of itself to bring about and 

 maintain with any degree of certainty such a depth as we require 

 to constitute this a first class port for the accommodation of the 

 large mail steamers." 



Happily the difificulty was overcome by the long delayed exten- 

 sion of the North Pier, with the results described. 



It must not be imagined, however, that with the advent of this 

 useful invention these bar problems have become any easier to solve 

 so far as the necessary works are concerned. Heavy dredging, when 

 unfortunately it is required to supplement the natural forces, involves 

 in some cases, a large annual expenditure, which must go on for all 

 time. 



It is, therefore, the first duty of the engineer to see that in the 

 disposition of the works, he utilises to the utmost degree, and in 

 the most effective and economical manner, any natufal forces avail- 

 able, so as to minimise the amount of dredging necessary : and it is 

 here that the problem is as great as ever. 



