GISBORNE OUTER HARBOR.

Gisborne Times, Volume XXVI, Issue 2147, 24 March 1908, Page 2

GISBORNE OUTER HARBOR.

- AMENDED PROPOSALS. DISCUSSED BY THE HARBOR BOARD. A sneeial meeting of the Gisborne Harbor Board was held yesterday afternoon to consider a supplementary renort from .Mr F. IV. 'Marchant, engineer of Timaru, upon tho report of Air Wilson, of the finn of Messrs Coodo, Son and Matthews, marine engineers of London, m reference to Air Marchaut s oiiginal scliomo for providing an outer liaibor at Gisborne. There were present Alessrs J. Townley (chairman), D. Henbum, W. Siovwrig it, JClark, tho Hon. Cant, Tucker, C. Alatthowson, F. Harris and J. AUun--1 ‘ I VIT Merchant's report was as folloMr Wilson, AI. Inst. C.E., a member of the firm of Cootie, Son and Matthews, Marino Engineers, London who examined on tlio _ ground and’ subsequently in consultation with mo all my proposals lor ail ou.er haibor at Gisborne, haying presen ed his report to the Gisborne Harboi Board, I submit tho. following notes thereon for tho consideration ot tho speaking, the Consulting Engineers endorse the advice an opinions expressed in my report ot February, 1907. They .agree to y well indeed with my estimates ol tho main structures of breakwater and wharf, but differ considerably in ie»Jeet of my estimates for plant and reclamation. (V[( , SITE AND ALIGNMENT DX. BREAKWATER.

In design No. 2, the Consulting Engineers accent trie site I proposed To the- breakwater, also the alignment of the first arm, but propose to modify the profile ot the outu part, though both -breakwater. designs terminate in the same position. in all these breakwater harbors the great bug-bear of shipping 1 “raime,” that is, oscillation ot the water which prevents vessels from iVhnr quietly beside the wharves. Having experienced the great di awbacks of this motion at three breaLwiter harbors, -with which I nave been or still am professionally connected,' 1 consider that eveijthni 0 possible should bo done to eliminate this undesirable factor. ~, , With that object m view, od” tho outer arm tog'vo. the sv eU running round tho end ot the bleak water “room to expand and consequently reduce itself in the shelteied area. There was also another reason • by laying olf the outer arm oi the’breakwater in the position shown on my plan there is room for a veil large vessel to swing at anclioi, be tween the wharf and breakwater. In the Consulting Engineer s modification of my design, the swell w ould curl round the end of the breakwatei and gather as it travelled -along tho leesido of the -breakwater, thus disturbing tho shipping- Also theio would not bo room in the mod’htd desi-m to allow a largo vesse to Rwiin’- at anchor. 1 do. not wish to undidy press this question of range, a d admit that, where a . nibble breakwater" exists, its effect is nothin" liko so strong and.harmful as tlio reflections which take pi ace Ironii the leeside of a solid X . but everyone who lias hail ox nerienco of the great disadvantage of a harbor subject to range ou | c } agree that everything possible should bo done to reduce l-* ciir>lfGvcd Mv -iilan provides for a shelteicu area of 77 acres over 24 feet m g which is none too largo foi luHiro expansion. The suggested modihcaHon in design No. 2 .reduces the sheltered area to 09 acres over 24 feet SXign No. 3 reduces R still further to 01 acres over 24 feet. The point is raised bv the Consulting Engineers that their modificatioi of “the outer arm as m design No. 2 allows of a future extension of the breakwater, whereas ray .design does not I may remark that it is quixe certain that no future extension of the breakwater, either m designs 1 or 2, would bo at all desirable. 1 further improvements and mcieasec quietness of water were rociuired m future years, a. light rubbto stono ...„11 chould be projected nom xno point 'west of Pah Hill Bay, towards tho end of the breakwater, Ravin •in entrance 600 feet wide or so between them. This, would lie vastly cheaper and better in every «n> than extending tho breakwater. Concerning design No. 3, uhich suggests that the breakwater might he shifted some 2000 foot seawards of Pah Hill Bay, I see many weighty objections to it, and no compensatin'' advantages. . ■ I selected Pah Hill Bay as .a harbor site because it has a smooth even bottom, with a good dentil of water extending fairly close to the shore, affording a calm basin close under tho lee of the breakwatei , offering also at the head ot the hay facilities for comparatively inexpensive reclamation. In fact, I consider it the only good harbor site n Poverty Bay. , , ~ If design No. 3 were adojrted, u would he 2000 feet further away Horn the town, and would cost soinev iat more nor ton to build than designs 1 or 2.' The breakwater would comme.i-o off a steel) coast, offering no advantage for reclamation. It would have 16" acres less of sheltered area than my scheme over 21 feet deep, and J have a strong suspicion, from trial soundings taken .about here, that tlio bottom would be found very uregular. , ....... The Consulting Engineers think it has -some merit over tlio Pan Hnl Bay site, in that it would be more accessible to vessels from seaward. 1 doubt it. The Waihora rock. wjlilc lie close to its entrance, and m any navigation about Poverty Bay it is certain that vessels could only safely -wohk ion beacon lines lor leading lights. At Pah Hill Bay there is abundance of room to steer clear of all obstacles, as the Consulting Engineers’ report allows. In order to make a fair companson between designs 2 and 3, prepared by the Consulting Engineers; I have computed areas and the ot of design No. 3 from the data from which No. 2 was estimated. They are as follow': Design No. 2, 69 acres over 24 feet, estimated cost £212,200

for tho breakwater, or £3,075 por acre. Design No. 3, 61 acres over 24 foot, estimated cost £190,000 lor tlio breakwater, or £3lll per acre of sheltered water. When all the other expenses are added to that of tlio breakwater, design No. 3 shows still worse m comparison. Concerning the sea slope -'4 > u breakwater, which tho Consulting Engineers liavo flattened from 2J to 1, to 3 to 1, 1 am quite certain, and know from my experience at Napier, having tlio sumo depth and. exposure, that blocks of the weight I specified will stand at a steeper slope than 2J to 1. Tho proposal to use a largo crano on tho nibble mound, in order to drop stones far out from tho tin, has been in use by mo at New Plymouth harbor for tlio last three years, wliero it is a necessity, but a hindrance. It should certainly never ho used whore it is jiossiblo to use tip wagons, as I beliovo can bo dono without staging -at Gisborne, and as has been done at Newcastle and other places in Australia. I have prepared a working scheme which I think would answer admirably for using tip wagons. Concerning tho rock pinnacles ontsido Pali Hill -Bay harbor, no doubt but that they exist. They, however, are quito out of tlio way if the Pali Hill site is adopted. AH tho Pali Hill Bay harbor area was most carefully tested for pinnacles and irregularities, and I am certain that it is entirely clear of obstruction. There was no occasion to re-discover rock pinnacles outsido the proposed harbor, which were quito harmless in relation to it. WHARF.

I am quite favorable to tlio use of ferro-conercte in wharf work, in fact think that it should bo used wherever possible or suitable. The wharfago question in any breakwater harbor in Poverty Bav is no easy one —given a depth oi 30 to 33 feet at low water, with a soft rock 'bottom, to build -a ferro concrete wharf capable of sorting the largest steamers trading to tho country. If such a steamer were moored to" a ferro-concreto wharf, it is a dead certainty that either tho wharf or steamer would be badly damaged immediately there was a rango sufficient to cause tho sleamer to bump sideways against tho wharf, unless timber spring fender pilework were constructed to keep tlio steamer off the wharf and cushion down tho side movements of the vessel. Ferro-concrete wharfago and spring piling on this principle is being constructed from my design at Napier harbor. _ . I am quite certain that the timber fenders attached to a rigid lerro-con-crote wharf ill tlio manner suggested by tile Consulting Engineers, after the method in use in- the quiet water of Auckland harbor, would not prove successful in breakwater harbors, subject to more or less range, as they invariably arc. Enquiry of any Harbor Master .in the Dominion who has worked shipping in the breakwater harbors would certainly confirm my statement in this respect. Ferro-concrete wharfage, with spring piling, could iio doubt be constructed at Pali Hill Bay on the principle designed by me for Napier harbor. This is a much cheaper system than [ designed originally for a ferro-con-creto wharf at Gisborne. I estimate tiie cost of such a wharf, on the Napier design, at not less than £65,000. . I did not see any shingle in tho country about Gisborne which was sufficiently dense and strong for use j a ferro-concrete. It may he obtainable, but would certainly be expensive. If tliero is none there, it might bo necessary to bring it by sea from Napier, which would add considerably to the cost. QUARRY AND PLANT.

There is a complete agreement between the Consulting Engineers and myself concerning the quarry proposals. I press, however, that the Board should have its own railway, and control its own traffic at all hours, without hindrance from anyone. , If the Consulting Engineers’ suggestion is carried out, namely, to Ouk tho quarry on to the Government line, and attempt to get the Gtoiio to tlio works in such manner, then I am certain that the result would bo so unsatisfactory that an independent line would have to ho eventually constructed. Probauly, also, tho rate per ton charged by the Government for liaulago would amount to moro than tho ißoaiel could lay its own lino for and pay tlio haulage, besides, after taking credit fur the value of tho railway materials when tho breakwater was comDieted. I am quite surprised at the estimate which tho Consulting Engineers have mado for plant required, stated at a value of £48,000. At e have to do things differently in this coun--1 I believo that not one of tlio breakwaters built oil a similar system in Now Zealand has over • had £20,000 worth of plant in use m connection with it. They have -been built with two or three locomotives, instead ol five, as proposed by the -Consulting Engineers. , , - Long hours, while daylight lasted, should certainly be worked on tiie quarry line, and two shifts of railway men would bo necessary for several months in the year. On looking again through the plant estimates I made lor my report, 1 find that an error was made in writing them into tlio report. The £43,000 quoted was for secondhand plant such as I know can bo bought ror less money. If new, the price should liavo been stated at £21,000, which would provide all that we should want. The sum of £3,000 should, therefore, have been added to my contingency fund. reclamations. Tlieso are estimated by the Consulting Engineers at £34,600. I liavo no idea how such a large amount lias been arrived at, and I think tliero must bo some misunderstanding about it. All tlio reclamation we want is a work and siding yard on the beach at Pah Hill Bay, and sufficient room at tho root of the wharf for the siding curves, and on which to erect a few small sheds for the Harbor Alaster’s use. Both these reclamations can bo made with papa rock, at .’mail cost. It might even be cheaper to form tlio splay at the root of the wharf with piling instead of filling, either method would suit well. CONCLUSION. I advise the Board to accept the Consulting Engineers’ estimate of £408,000 for loan purposes. With proper and experienced engineering, I believe that the work can be carried out on my plan for much less than my estimate of £331,000, plus £B,OOO, contingency fund omitted. The limestone in the breakwater should be deposited for less than 3s a toil, and ! am certain that the rubble mound will not require to he of the dimensions allowed for in the estimates of either tho Consulting Engineers or myself. Further, in connection with the rubble mound, I am of opinion that more than 25 per cent of the mass in tho bottom and middle areas might be built of papa rock from the Pali' Hill cliff, resulting in a large savin" of cost. The papa- withstands the break of flip sea' excellently well, as can be seen at the place in question. If this cliff was mined, and the largest and best blocks used for breakwater hearting, leaving the poorer quality for use in reclamation, 1 see no reason why the breakwater should not be as sound and permanent, when this softer hearting was thoroughly well covered .with A\aibere limestone, as if the work were entirely formed of the latter. It would not do to reckon on this when making an estimate of cost of tlio works; but, in the course of their construction, the trial should certainly be made, and would doubtless be successful, resulting in a great saving of expenditure. There should also be a large saving, say. of £25,000, on the plant, and £20,000 on the reclamation estimates of the consulting Engineers, while they have also allowed liberally for contingencies besides.

During Iho lisb thirty years, in this country wo have built lip an extensive experience in marine engineering, the ascertained facts of which must override the opinions to tlio contrary of tho most eminent experts from 'outsido it. Our circumstances aro peculiar, and uttorly dissimilar to those under which old communities, having cheap labor and plant, established usages, and all sorts of conveniences, may carry out their engineering works. In many directions wo break away from precedent and time-honored methods, and sometimes attain excellent and economical results in consequence. At Timaru, for example, fiir John Coodc, the most experienced marine engineer of his day, declared it was impossible to construct a breakwater across tho hugo shingle drift existing there, and subsequently preserve it from destruction; yet it has been done, it still exists, and will continue to do so. Thor© wore unexpected factors in tho caso, which neither Sir John Coodo nor anyono else foresaw, and which helped tiro work to a successful result. ' Again, at New Plymouth wo aro extending tho breakwater on a most economical system, and which is proved to bo slablo under the attack of the heaviest storms of the p.fst threo years. On explaining the system of construction to Mr Wilson, I remarked that, if we had submitted tho scliemo to his firm, I was quite sure that they would have thought it so great a departure from precedent and orthodox practico that it would not liavo been sanctioned. He agreed that their consent would not liavo boon given. The result is that wo aro building for less than £SO a foot breakwater work estimated to cost £75 on a more orthodox system. The fact is that in many directions marine engineering is of necessity very experimental. One never really knows what ho can or cannot do with breakwater work until he tries; there aro too many unknown quantities and disturbing factors to allow of absolute certainty. It is, howeve'r, alwaijs safe and permissible argue from the results of similar works which have been built under approximately similar conditions in the samo country. TIMARU, Feb. 20. To the Secretary of the Gisborne Harbor Board. Dear Sir, —Yours of February 14 duly received. I immediately went fully into the whole of the matters referred to me, and eud .dy them in notes on the report of tne consulting engineers, of which I 6end you the original aiid duplicate copy. I also return the plans sent by the consulting engineers, of which I have had copies made for future reference.e The Board will, of course, do as it pleases about referring the matter to "another expert; but ,for my own part, I cannot see tho use of it. The consulting engineers and I agree that the site should bo at Pah Hill Bay, that it should be built of rubble from Waihirere, that there will be no sand drift to cause shoaling or expensive maintenance, and, generally sneaking, on all the major points aro agreed. The alternative- site, seaward of Pah Hill Bay, must have occurred to Mr. Wilson- after his return to Auckland, I think. He had no idea of it when I met him in Auckland, and the subject- was never discussed or hinted at during our consultation. He is, I therefore think, merely making the suggestion without knowing what I have to say against it, and in default of an inspection of the site ho has -suggested, after having left tho country. If the Board accepts the consulting engineer’s estimate, as I think should be done, then there will he a superabundance, of money to carry out tlio scheme.

Having agreed on major points, all the details of plant, reclamation, timber and ferro-concreto wharfage, papa rock hearting for breakwater, all these may bo left to develop themselves as tho -works como in to bo constructed in earnest. It is impossible to obtain -unanimity in these matters. Tho point is, to construct the works as cheaply and effectively -as possible. During the construction of tho works, all sorts of things will require variation and modificaaion, as has occurred in every work of such magnitude; and, therefore, it seems to me unnecessary to strive after a complete foreknowledge of all details, when these will of a certainty have to be modified as necessity arises. Tho great thing is, to agree on tho main points, and to liavo plenty of money to work If, however, tho Board should still desire to engage another expert, I suggest that Mr. Cyrus Williams, M. Inst. C.E., Engineer of tho Lyttelton Harbor Board, should be consulted. I suggest him because ho has lately designed a similar work in connection with tho proposed Christchurch ship canal, and has had the advantage "of a long professional intercourse with Mr. Wilson concerning it. It therefore occurred to me that lie would be a very suitable man for this particular purpose. If the Board agreed to this, I could lay all my views before him in Christchurch, and he could advise accordingly.— Yours faithfully,' F. W. MARCHANT. lie Waihirere -stone: I noto that the Board proposes to have this stone tested for strength, etc. I suggest, instead, that, as tho Grey mouth breakwater is built of limestone of quite inferior quality to the Wailiirere material, you should ask the Greymoutli Harbor -Board to send you up a fair sample of the limestone in their breakwater —say, a hundredweight lump—and you could easily compare it with the \\ aihiroro stone. If the limestone used in tho breakwater is good enough to stand permanently, there can be no doubt whatever about the Waihirere stone being all that could be wished in that direction. I consider it is splendid stone, and there is abundant evidence of its permanency in tho big blocks lying about there without the least- sign of weather-wear. Limestone hardens up considerably after it is quarried from its solving or destructive action on it solving or destructive action ou it whatever. —Yours faithfully, F. W. MARCHANT. Mr. W. D. Lysnar wrote regretting that lie was unable to attend tho meeting, and suggested that tho Board have the- alternative sites sounded and swept, so as to ascertain if there was any foul ground. Until this was done it- would be impossible to judge tho position of the breakwater. Mr. Merchant specially cast a doubt on the alternative site suggested by Mr. Wilson, on account of the want ol survey information; but when this knowledge was obtained, the Board could consider getting the opinion of a third engineer. It would seem to him (Mr. Lysnar) that tho alternative site was not a good one, because of the foul ground. If the survey disclosed good ground there would would be a conflict between the two reports, and the "opinion of the third engineer would -be valuable in selecting a filial site. He suggested that- the of a third engineer be left over until tho survey was made. The Chairman said -Mr. Marchnnt was strongly in favor of his own plan, with certain modification. Taking the report, it was shown that- the Board did right in referring the original scheme to Messrs. Coodo, Son, and Matthews, The most important point was the question of oscillation from the range which prevented vessels lying still at the wharves. Mr. Marchant’s plan had only one closure, while "the Timaru breakwater liul two. He thought it would be a geod idea to refer the plans to the /arums captains of vessels using the port to get the opinion as to whether the scheme would supply what was captain spoke well of the scheme :tho Board could then further consider the details. Ho moved, —“That- the plans and reports be forwarded to various shipping companies, asking them to get tho opinions of their captains as to whether the scheme, as proposed, was a safe one, especiilly at night-, and in rough weather, tlso as to whether the sea-bottom. i

being of rocky formation, was safe .or dropping anchor. Tho captains called at"various ports in tho world, and before the- Board went too far, it might bo -desirable to have tho opinions of oxncrrts who would liavo to use the harbor. Mr. J. Clark said ho agreed with tho suggestion of getting tho captain’s opinions. lie would also like tho opinions of another export engineer before tho Board sanctioned such a largo expenditure. Too much caution could not ho used. Ho would also like tho opinions of tho shipping masters forwarded to the superintendent of marine. They all knew that tho Timaru Harbor Works had been a success to a certain extent. Tho Board should engage another first-class engiucer to report upon data and surveys made by hi in soil, independent of any information from either Mr. Marchant or Mr. Milson. Ho was suro the district could afford £500,000 for a breakwater, if it was a breakwater, and would make shipping safe; but ho would not like to seo money spent upon a similar harbor to the one at Napier. Mr. Siovwright agreed- .with . the chairman’s motion, and said that all advico that would help tho 'Board should bo obtained. Ho was not adverse to getting the opinion of ail outside engineer as suggested by Mr. Clark. Tho whole report was experimental, and tho Board should know the efficiency of the work before anything definite was decided. Mr. Mattliewson said ho _ would veto against tho motion. Captains or vessels were not engineers, and were often very biassed men. _ Ho would rather see an outsido engineer engaged, as suggested by Mr. Clark. There was a certain amount of experimental work in the report, but all such works were very much ct an uncertainty. There was a good deal of agreement between both engineers that had reported, but it required a- local knowledge to understand tho action of tho waves that would beat upon the breakwater. ■Whatever was -done should be done well, and money spent upon expert advice would not be wasted. H there were 40ft of water at the wharf the largest vessels could come in, and the Board should have the opinion of a marine engineer on the soundings. . . Mr. D. Henburn said it was a different thing building an outharbor at Gisborne to the construction of a breakwater at- Timaru, Napier, or New Plymouth. Poverty Bay was not an open roadstead, hut was well sheltered. He agreed to tho suggestion of obtainng the -report of a third engineer, but- not from the captains of vessels. At the suggestion of Captain Tucker, the motion was altered so as to ask the opinions of directors of the shipping companies, as ifc was felt they would he able to get more informataion than their captains. .Mr. Harris supported the suggestion that a third engineer be consulted. Captain Tucker held that the Board should not take the highest step ou the ladder until they had reached the lower one. _ He would second the amended motion, because he felt thero was a. great deal of uncertainty in tho scheme, and it would be a great disappointment to find that a harbor had been constructed to serve a certain class of vessels, and the captains of those vessels declined to use it. The Board should aLso get an opinion from a third engineer, hut the getting of advice from the .shipping companies would not prevent that from being done. Mr. Mattliewson suggested that the Marine Superintendent should be also consulted. The Chairman said ho was sure the information would be valuable. The shipping companies could not say that the scheme was rushed through without- their being consulted. The motion was amended was then put and carried. The secretary was instructed to obtain sufficient tracings for plans to be forwarded to each of the shipping offices. The proposal to consult a- third engineer was not discussed. OTHER BUSINESS. Mr. P. MoLouglilin, with the consent of the station-master at Gisborne (Mr. M r . Day), asked permission to extend the present railway lines on the wharf to the crane, near the Turangamii bridge, so as to unload piles from the barque Mary Isabel, direct on to the trucks. Permission was granted.