NAPIER HARBOUR

Hawke's Bay Tribune, Volume XVII, Issue 208, 17 August 1927, Page 8

NAPIER HARBOUR

COMMISSION’S INQUIRIES MH HOLMES’ EVIDENCE FINISHED. The Napier Harbour Commission resumed its sittings in Napier yesterday. Continuing alter lunch Mr, J. D Holmes, ol R. \\. Holmes and Sous, consulting engineers to the Napiei Harbour Board, dealt with the harbour at \ izagapatam. between Madras and Calcutta, stating that it was a po r t on a parallel with that of Napier, the many peculiar features being almost identical. The port was situated on a shallow buy about tour miles across inland of which there was a large lagoon into which the Moonderu river flowed. The outlet varied from 600 feet to 120 feet wide. In the early days coastal ships used the port, but silting up occurred on the bar. In 1877 the port was first advocated and in 1882 Mr Parkes, an engineer from England, examined the place and stated that any designs based upon the knowledge available would be fruitless. In 1891 Sir Alexander Hennele suggested training walls across the bar hut added that further information was required. In the following year Mr. Thoroughgood. engiilver of Madras, investigating, lo(md that the tidal flow was very low and consequently recommended an outer harbour. Nothing was done in regard to that. In 1906 Mr. A. T McKenzie made a detail survey, taking borings and recommending an outer harbour. At the same time the Public Works Department of Madras nut forward a scheme of a detached breakwater out to sea from the bay In 1908 all these suggestions were submitted to Sir Alexander Rendal’. who suggested n small outer hnrbnur During the next year Sir William Matthews reported submitting a design for an outer harbour. VTZAGAPATAM HARBOUR. In referring to the construction oi the harboui at Vizagaputam (India) witness said that neuher Sir Alexander Kenuah or Sir William Matthews were given an opportunity oi inspecting the site. Both alluded to tue uimcuity oi reporting wiiuuui making a personal investigation, tn 1912 Sir I‘rancis inmni, engineer to Madras Harbour, visited the port and recommendea an outer harbour, saying chat it would be too costly io dredge out a scouring basin. In 1914 Mr. A. Lyster was in India and the opportunity was taken to get him to report on the sclieine- ne suggested an inner harbour with training walls out to the 20 teel mark. The channel at the beginning was to be dredged to 24 feet below datum, it was to be 000 ft between the moles. He also showed possible extensions of the piers in case the unit proved too great. The basin inside he proposed to dredge to 30 feet lielon datum. Owing to the war the work was shelved, in 1921 the necessary land lor an inner harbour was purchased and .in 1924 the Indian Government decided to do the work with the help of the Bangor-Na rpur Railway Co. The services of Lient-Colonel CartwrightReed from the Admiralty were obtained. He was instructed to prepare plans lor a scheme put forward by Lyster. He advised not to build the piers until an experiment was tried of maintaining the channel bv dredging. This was rather interesting in view oi first-class rock being secured to the south of the lagoon. Colonel Cartwright-Reed submitted a comprehensive scheme providing for dredging out of scouring basins and taking in the lagoon and 1800 ft of wharf. The proposed depth to begin with was 30it at the wharf and the same depth in the channel, having a minimum width of 300 ft. In the channel 55,000 cubic yards of rock had to be removed- All dredgings were to be used for reclamation and the work was to cost £1.500,000. The winds were south-west in the summer and north-east in the winter. Both winds blew, at right-angles to the channel. Work was now being vigorously undertaken at this harbour and it was an interesting fact that the current came almost straight out while the vessels had to turn into the harbour at an angle varying from 45- degrees to 90 degrees. That was just the opposite to what had to be done to the Inner Harbour at Napier. Witness here stated that the winds referred to were monsoons. WIDTHS OF CANALS. \\ itness then quoted the following canals with accompanying widths:— North Sea Canal, first made to 164 ft, was widened to 368 ft; Manchester Canal, 1641 t; Suez Canal was 98frat first being widened to 147 ft; Panama Canal, 300 ft width. Witness stated that when passing through the entrance to the Culebra Cut they passed another vessel of the saine size, while on the port side was a dredge, the bottom width there being 300 ft. The Clyde at Glasgow was dredged to 350 ft. At Detroit there was a canal connecting two lakes. It was approximately 21 miles long and 200 ft wide. Vessels up to lO.OlX) tons were using it. Montreal, on the St. Lawrence, was between two rapids, being the only place that steady water was available. The harbour was dredged out of the side of the river, being used by vessels much larger than those which come to New Zealand. As far as witness could remember the current was about 6 knots. When the vessels came through the rapids to slack water tugs picked them up, drawing them into the harbour. Witness produced a book containing records of all ports of the British Empire and of foreign countries. Witness stated that he wished to cal! attention to the low water depths at many of the harbours, particularly Cardiff, which was partly dry at periods, part of the channel being five feet in the air, yet a tremendous export coal trade was carried on there. The tidal range was about 30ft.

Mr Holmes then referred to the position oi the harbours in all port towns. At Auckland, he said, the shipping centre had a tendency to move from the water front to Karangaliapi road. At Wellington the shipping centre was moving towards Courtney Place. At New Plymouth the town was 2V miles from the port and was extending towards Fitzroy which was further away. At Nelson no attempt was being' made to extend towards I he port, which was ]J miles away. No tendency could lie found in Invercargill of the town moving towards the Bluff. Rockhampton. in Queensland, had two ports, which were 40 miles distant. In London the shipping centre was

at Tilbury, 20 miles distant from the metropolis. New York was a good example of what occurred when there was not a sufficient area adjacent to the port to allow for expansion'Hie port was moving towards Newark and other places in New Jersey. Referring to samples of borings taken by Mr. Pengelly, three more had been found, being numbers- 38, 41 and another labelled Inner Harbour channel 21 to 35 strata. He also exhibited a plan of the Brisbane river showing what could be done in the making of a channel in the open sea. With regard to navigation, he wished to point out the direction in which vessels approaching the outer harbour would have to steer. It was considerably further out than suggested in some of the evidence.

Mr. Barton ■ That is really a point for nautical men.

\V itness said that in regard to the maritime evidence given by some of the witnesses lie would say that the moles at the entrance to a harbour were plotted m relation to an approximate sailing course which was fixed by certain contour lines revealed by the soundings. These lines and the approximate sailing course indicated by Cullen <fc Keele would not permit of the course as shown by witness as to how they would steam against wind and sea. TENDENCY TO SCOUR. Witness drew attention to a vessel entering a channel approximately in the centre, saying it would be about 300 ft off ol what could be termeu a channel as they would be steaming along what would be called a lee shore and he did not think that any skipper would take a vessel in during a heavy sea as the seas in this neighbourhood were in a very confused state when heavy seas were running. With regard to the Inner Harbour the soundings showed that without any assistance except with the small dredged hatch the bottom had been eroded being now nearly 1000 ft for a portion of the channel’s length. He felt certain that if the channel was cut through there would be a tendency to scour. They had allowed for dredging the tidal channel the same as the basin for some distance up- Once the channel was dredged there was no doubt that the velocity of the current would be greatly reduced. Witness then referred to Cullen & Keele’s remarks regarding navigation in Moreton Bay. pointing nut that ships were continuing using the ports during rough weather when there was not more than five to six feet of water under their keels.

THINGS TO BE AVOIDED. In his professional research witness said that the whole effects of his deductions was that breakwaters were to bo avoided if possible and that seemed to be the opinion of many and various engineers who had made life-long studies on such questions and who were recognised" to be the highest authorities on harbour construction in the nations to which they belonged. Witness could not see any reason why the examples of th? leading engineers of other countries should not he followed here In io case had a breakwater harbour been built when it had been possible io construct an inner harbour To Mr. Gray: He was satisfied that an Inner Harbour could be built m the lines suggested bv Cullen and Keele for the accommodation of large ships. Ho was of the opinion that a considerable amount was to be accomplished by dredging. He had had a fair amount of experience in dredging ill different parts of New Zealand. In regard to navigation he had studied the profession most closely. The time required in getting up steam on ordinarf sized vessels, in the case of coal-burners, was about 24 hours, while in the case of water tubed boilers like those on battleships could be got up in 20 minutes. Regarding the proposed tide deflection witness stated that most of the current from the Westshore bridge flowed down in that direction. Dredging in the channel opposite the tide deflector would greatly reduce the velocity at the entrance. The deepening of the channel was a factor that would work the other way but he had not worked out what the effect of the choke by the Westshore bridge would be, but it could be expected to. be reduced. WITNESS’ WIDE EXPERIENCE. Witness had inspected during thecourse of Ins experience harboui works at London, Southampton, Aberdeen, Boulogne, Plymouth, Philadelphia, Washington. Teledo, Montreal, New York, Glasgow, 'Leith, The Tyne and others. His first experience in harbour designing was cranes for the Greymouth wharf. At Tauranga he designed a new wharf for the Public Works Department. He designed Karori rock lighthouse, following the wreck of the Penguin, and a number of automatic light stations. He had been in partnership with his father since 1922 and they were consulting engineers to the New Plymouth Harbour Board. They had reported on the Gisborne, Timaru and Patea channels, and at the present time were consulting engineers to the Nelson Harbour Board. They had carried out foreshort protection works at Wellington. They had kept in close touch with all works done at the various ports, keeping up-to-date with the latest modern harbour methods of construction.

This concluded the evidence of witness and the Commission adjourned until to o’clock this morning.