REPORT ON MANUKAU HARBOUR.

New Zealander, Volume 9, Issue 746, 8 June 1853, Page 3

REPORT ON MANUKAU HARBOUR.

(From the "Auckland Government Gazette.”) Her Majesty’s Surveying Vessel Pandora , At Sea, May 3rd, 1858. Sir, —I have the honour to forward, for the information of His Excellency the Governor, this report upon Manukau hard our, the Survey of which was completed to-day, and I have the greatest satisfaction in informing His Excellency that there is a straight and direct channel of considerable breadth into this harbour, through which, 11.M.5. Pandora passed to-day at near low water in 4| fathoms. At spring tides low water, there is not less than 3.V fathoms, at high water not less than si. 'The straightest line out of Manukau having the three most conspicuous objects in transit, namely, the Nincpin, the extreme of Paratutai, and the extreme of Poponga, was the course we steered out, which 1 felt so sure from observation was a clear channel, that wc carried studdingsails over it, at low water. Thereby divesting the entrance of Manukau harbour of a great proportion of a bank, that has hitherto been laid down as facing the harbour. There is certainly least water on the position of tills bank than elsewhere, nor do T deny that it is possible there may have been still less water, but it has not been crossed before, except I believe by Vessels, surprised to find themselves in safety on the other side.* Hitherto thcic appears to have been little known of the access to this harbour, or of the depth of the channels within, and a strong prejudice has existed against it, for reasons I will attempt to clear up, for some of these we are indebted to accidents as proof of its practicability. First.—lt is a common error to believe that the breakers extend connectedly across the Heads, because when viewed from Poponga the middle bank which is always breaking, faces this view. Secondly. From the land about Paratutai it will appear to break across also, for the Orwell and middle bank would bore over-lap. A similar cause occurs when viewed from the foot of the South head, but, once in the channel, between the Heads, and the sea is open before you. Thirdly, It appears that the Eclair , ami small traders have fallen into the same error, and have preferred waiting for an opportunity to pass through a shoal and narrow passage near the South head, which frequently detained them for days, when such Vessels could with facility have beat down with the tide, having never less than half a mile in the channel, and increasing in breadth from Paratutai outwards. Now, Sir, in regard to changes that may have taken place in the entrancesto Manukau,although the above reasons explain away the want of belief in a fair channel, they in no degree effect the accuracy of the Survey of Mr. Ormsby, or the more recent Survey of Mr. Smith of 11.M.5. Acheron. The former gentleman delineates a channel after passing the middle bank, without, it appears, having intended to go directly out. Mr, Smith has corroborated it, and added many soundings, and he shews also a North channel of half a mile wide, of three fathoms, but having given us the outer bank without soundings, we conclude he did not cross it then becomes a question whether this has undergone a c’.iange, if so, a change of great benefit, giving a fairer channel in, and whether the Northern channel which appeared to us to be breaking considerably at the depth given, is not in consequence less eligible. On entering Manukau through the Ormsby channel, when there was a tolerable South swell, we remarked that the position of the outer bank did not break. Subsequent observations by officers stationed at tiie Heads, confirmed this, gud the master and myself crossed the outer bank in a boat, but an unusual fog coming on we were thrown entirely out of the line being unable to see Paratutai; we however into deep water over that shoaler portion ol the bank near the North channel having only 11 feet (Low Water Springs.) We found on laying down the work, we had crossed to the Northward, and therefore it did not deter ns from taking the straight channel out in the Pandora , which we did on the day after a westerly gale, without a breaker. I have been thus particular. in bringing this portion of the report to notice, in order that unnecessary expense may not be incurred by establishing a fixed light'house, where it might possibly be an advantage to shift it. My opinion is, that it is quite possible that the configuration of sand banks subjected to the joint influence of tides, freshes, and gales- are liable to vary, and yet I think it more than probable that the present straight channel should remain, as it has taken (if indeed it ever shifted) its natural course, the direction of the Harbour. * I have been disappointed in obtainii g the information regarding vessels which bare gone into taa under (hose circumstances.

Besides this channel into Manukau, I have already mentioned another laid down to the Northward, half a mile wide, having 3 fathoms water, but I should neither recommend it, or _ the small intricate channel to the Southward, since we have a direct and deeper. The soundings, on approaching Manukau from seaward, decrease very gradually. The extreme of the outer bank channel is three miles from the heads, the depth of water in steering in between the Orwell and South bank varies from 8 to 16 fathoms,—- these banks are steep too, and always shewing. In the channel only it breaks in gales at the shoalest part; in ordinary winds it certainly does not. During three weeks the officers were employed about the Heads, it was not seen breaking, 1 although strong winds prevailed. At the mouth of the harbour the channel decreases in width (half a mile,) this is off Paratutai, or North head, and here the tide runs 4 knots at Springs ; at the outer channel tides rarely reach two. * .. . The South Head is a mile within the North head, and has a spit extending half way across towards Paratutai, but there is now a clear deep channel towards Karangahapi, with a bold shore Off Huia on tile N6rth shore, three miles from Paratutai, is anchorage in five fathoms, but the anchorage after rounding Karangahapi is the best in all winds. Or if it is intended to go to the Waiuku or Papakura, there is anchorage within Kauri point opposite. From these points Manukau expands to a breadth of 16 miles byjl2, having three channels navigable for vessels of any tonnage to three equidistant and most valuable districts, viz., Onehunga, Papakura, and Waiuku. These channels are with small exceptions nearly straight, and having dry banks on either side at low water, they offer a sheltered anchorage at any point. The channels continue their depth to within the Heads of Waiuku and Papakura, and close up to Onehunga. ’ j ” There are besides two deeper channels leading along the North shore, the one branching off Onehunga, middle channel at Shag Point (Okewha) to the Wuhan portage, and joins the middle Onehunga channel off Matengahe or Cape Horn, though at this point it is only navigable at high water. The other outer Onehunga channel, comes up direct from Karangahapi, and would have been the best channel to Onehunga, but it fails in depth where it enters the mid channel, it is useful to the lands around Pukitutu, and indeed is generally available, as it would have 22 feet at high water where it is most difficult. The general nature of the bottom of all the channels, is a greenish sand and mud, good holding ground. The tides within them average at springs 21 knots, there are no rocks, and no uneven ground, and the banks being soft sand and shells are not likely to injure a vessel on touching. One tide will suffice to carry a vessel from the heads with a leading wind to any of the above districts. It will be observed, these remarks are suited for vessels of any burden, but the Manukau flats can be traversed by boats according to the tides, and unlike the banks outside, here we have the smoothest water over them, the tide taking the course of the channels. The banks are generally covered soon after the first quarter flood, but they vary in height, and some are never uncovered, especially those facing the Waiuku channel where there is generally 4 feet at low water, and only small spots that dry. Having made these general observations on the channels, I come to their more immediate description. Onehunga middle, or main channel, leads along the coast from Poponga. A flat extends from Karangahapi off which is the anchorage. From Karangahapi there is a straight channel to Shag Point (Okewha) one third of a mile broad with 4.V fathoms at low water. The distance Irom Poponga to Shag Point being 4| miles. Here the channel divides, the inner one along the Aluta Karaka having- a. depth of ! li fathoms near the portage, but as before mentioned difficult at Cape Horn. At Shag Point, (Okewha) the channel splits, the inner running along the coast. The main channel here is scarcely a of a mile, and strikes off to the Westward, and gradually curves again to Cape Horn ; just before reaching Cape Horn, there is least water, it is where the three channels join, at 13 feet, low water. (Matengahe,) or Cape Horn, is 2| mile below Onehunga, it is steep too, as also are some of the other points before reaching Onehunga, and as the flat extending from the town renders shipment very inconvenient, I think-these Head lands will he valuable, besides being about the nearest points to Auckland. And the anchorage is wider than that immediately off the lower end of Onehunga, where there is however a pool of 3 fathoms at low water. The general anchorage for Onehunga, would be below the White Cliff or Tetapere. The coast up to Onehunga is generally formed by low perpendicular cliffs. There arc two broad creeks of no depth, besides several smaller streams in the various bights. The points arc of a soft grey level sand stone, extending in straight layers from the points to the S.w. hut in some instances taking a curve! inear form. Karangahapi Bay has deep iron sand. The Papakura channel cutting through the middle of the flats is 12| miles in length, lias 8 to 10 fathoms for the first three miles, and never less than 4 to within the Heads where there is 4£ fathoms. The Wata Paka falls into it 4 miles up having 3 to 4 fathoms for two miles, when it becomes narrow and winding with j a fathom to its head. The Pukaki joins two miles above this having a good boat channel. The Waiuku channel commencing from Te .Hohono point opposite to Poponga, is six miles to its Heads, averages 8 fathoms, decreasing to 4 I near the Heads. There is a hole of 17 fathoms at the entrance and (I fathoms after passing the Heads in which depth there is anchorage a mile within. Vessels not drawing more than 12 feet can go up as far as the needles, H miles from the pov# tage. The Taihiki, a tributary one mile within Karaka Point, is navigable for craft drawing 6 feet water, for 2 miles. The channel into the Waiuku is along the coast, and it is generally steep from point to point. leaving shown that Manukau possesses three channels’foidned by nature, of sufficient depth to allow the largest vessels to enter into the heart of the country at three equidistant points, it is unnecessary and would be presumptuous in me to describe a surrounding country so well known. In framing this report of the hdrbour, we should be doing injustice to the subject, if in proving its easy access we lost sight of the most essential questions, is it always sol—and is it so at Night 1 I am not prepared to recommend a vessel to run for Manukau in a gale, for on such occasions there would be a continuous break, and leadingmarks might be obscured, fortunately such gales however frequent arc not of great duration. As to entering at night 1 should consider the light on the extreme of Poponga as a leading marie to such persons who have become acquainted with, the Port, and especially in command of a steamer, fur which Manukau is peculiarly eligible. When a flag-staff is established on Paratutai, vessels can be guided as at Ilukiang.i, the dipping of the Arm would make known when a vessel is too far over either way, and when this is osta- ; Wished vessels will not fear working out with the [ tide. His Excellency, 1 am aware, is tully prepared I to give effect to any means benefitihig tins harbour, and as a sea iii an I constate I believe nothing would add to the confidence of intending visitors

more than the establishment of the signal station. From the station, One Tree Hill near Onehunga being conspicuous, might he made the medium of communicating with Auckland. The reports of the levels from two different points of the Manuk an, as well as sections and plans, have already been delivered by me to tho Colonial office. The interesting and valuable levels from Waiuku to tho Waikato, 1 am assured are satisfactorily completed, and 1 only remark that it appears to me a matter of consideration in forming tlie canal here whether it would not be done more reasonably and effectually by cutting through the morass as far as the woods which from (1 acknowledge) casual observations would save at least half the distance, and the same water could ho turned to this channel. A similar cut through the forest would undoubtedly be a work of great labour, hut, fortunately, here it is not needed, as the course is comparatively much straighter. The clearing out of this portion of the Awaroa which endangers the navigation of canoes and renders that of boats almost impracticable, could he done I think by the desire of His Excellency. The impediments are trees, that were principally thrown across by the Waikato tribes to prevent the descent of the murderous E’ Hongi, and have been no doubt added to by the occasional undermining of trees during the freshes. It is well known that many valuable native cargoes have been lost and damaged, in consequence of- these obstructions, and 1 find on enquiry that Hie Natives only require a little well timed advice, and perhaps small assistance to remove an obstacle that is at the present moment impeding the trade to Waikato. If it should he hereafter determined to cut the canal to the forest, independent of.the Serpentine windings of the Awaroa until reaching the forest, it would appear to me that a swamp of moderate breadth about a of a mile west of Mr. Constable’s Inn would offer a less level than a direct line from the creek there, hut upon this point I offer suggestions with deference, and only to open a consideration on a point probably already better determined. The survey of this harbour on a large scale, (six inches to a mile) was made at the request of the Colonists, conveyed through LieutenantGovernor Wynyard, and I have no hesitation in recording the names of the officers employed during part of a most unseasonable summer which prolonged our work. The open boats in which they and the crews lived and slept were absent from the ship in the channels for a fortnight at a time, hut no casualty or sickness of any kind occurred. Mr. Kerr (Acting Master) and Mr. 11. Kerr wore employed in the Maori c tier, in sounding the outer waters The latter officer, also with Mr, Stanley, Master’s Assistant, walked and surveyed the coast lino from Kaipara Heads to Manukau. Mr. Oke, 2nd Master, with Mr. Ellis, conducted the investigation of tHe Papakura and W aiuku channels, and Messrs. Blackucy and farmer sounded and surveyed the three channels leading to Onehunga, Mr. Bhackney also accompanied me in the survey of the Waikato heads. I have also much pleasure in mentioning the zealous maimer in which the work was carried on during my necessary absence, by Lieutenant Jones. I annex the time of high water, full and change at different points. A description of the site tor signal and light stations, as well as the number and description of buoys and perches required for each channel. The position for these buovs are marked on our charts, and I will immediately place a tracing of the entrance and Sailing directions in the Survey Office. Relative to the site for a signal station and light house :—- After examination, we find that there is no place so well adapted as Paratiitai for the former. Although steep, it is sufficiently accessible and can be made much easier; from the summit is an ex Tensive view seaward in all directions, wjliell COllld not he obtained below. The flag-staff wculd boon the Apex 310 feet above the sen, here is 80 feet by 30, Immediately below this (but ou Paratutai) there is a site for a dwelling, with about half an acre of ground having soil 3 or 4 feet deep. The only difficulty is water, which must either be'supplied by a tank, or from a stream which runs near the foot of Paratutai. By the flag staff, a light revolving or colored, to be distinguished from Native fires, would he a guide to the entrance at night, but cannot be available to lead vessels in. But if a light was placed on the outer extreme of Poponga it would be always eclipsed by Paratutai, when a vessel was too far to the Northward, and by keeping it just open, it is in reality the same mark as given for steering in by day. In buoviug off the channels of Manukau I think two large buoys are only necessary, because the marks, with the Orwell and mid bank forming such decided sea walls, are sufficient. The two outer buoys should be large can buoys, and laid down with the best gear, I hove marked the position. The spit off the South head may have a smaller buoy. Those at the fail of the banks forming the three channels should be of the same description, whereas, the buoys for navigating the channels, need only be cask buoys. For llie Onehunga channel, to Onehunga 11, and 2 perches are required. To reach within Papakura heads, 9 are required. To reach within Waiuku heads 3 buoys, and 3 perches. The positions of all these will be seen from the chart. In laying down these huoys (especially the outer) the person in charge ot the signal station should he practically acquainted with their position, and any one or more of a crew stationed at Paratutia might be in the same way made competent to pilot a vessel through any branch of the Manukau. A vessel foom twenty to thirty tons should be employed in laying down the outer buoys according to the weather, between December and March. Hi fine weather it would occupy but little time. Total Number of Buoys required. Large Can Buo} r s 2 Middle-sized ditto 4 Onehunga main channel ) Cask -j and inner ditto j Buoys Papakura chain:el ditto fl Waiuku channel 3 Total-r-2 large, 4 middle-sized, and 23 small. There are also required— For Onehunga channel 2 perches. For Waiuku 3 Total ... o High Wat eb, Full and Change, in Manukau.

1 have the honor to he, Sir, Your luobt obedient servant, Byuon Drury, Commander and Surveyor. To the II : . the Colonial Seerelav. . he.

At tlie Heads ... • ■£ *10 m. CO Popoaga 10 C 5 Waiuku Heads 10 ro “ Portage 10 f o f> Papalcura Heads 11 CO Cuehuoga 10 CO o / r r t Summit of Paratntia < V 1 ‘ .37 03 S 174 ( J.OHg. Variation ... 14 fli. Rise and Fall at Springs ... ... 1 net. “ “ Neaps G to 7 do