SRAPLANE BASE FOR CITY

Press, Volume LXXII, Issue 21908, 8 October 1936, Page 18

SRAPLANE BASE FOR CITY

ALTERNATIVE SITES INVESTIGATED

RBPORT TO HARBOUR BOARD

“It will be seen that the necessity of a seadrome for large flying boats is not an urgent matter for Christchurch, and that efforts should be concentrated upon the construction- of the municipal aerodrome for the city, as there is continual evidence accumulating that this is becoming a provision of everincreasing urgency.” In the foregoing paragraph the Christchurch city engineer (Mr A. R. Galbraith) and the. Lyttelton Harbour Board engineer (Mr P. W. Fryer) sum up their conclusions in their report upon the proposed sites for a seadrome for seaplanes and flying boats for Christchurch. Consideration of the report, which was tabled at yesterday’s meeting of the Harbour Board, was postponed until the next meeting of that body, to enable members to make a thorough study of its contents. The report gives a long comparison between the merits of the Lyttelton and Estuary sites—the only two included in tne order of reference for investigation—and finds that the advantages are decidedly in favour of the estuary from the practical and economical viewpoint, but it is noted that there would not be in that case sufficient area for the Port Christchurch scheme, should such be executed. At the same time, it is stated that there are two other sites, namely, Akaroa and Lake Ellesmere, the possibilities of which should not be overlooked, and might be examined and reported upon should further investigation be required. Auckland the Main Base Dealing at first with a survey of the development of aviation during the last decade, the report summarises the position in the Dominion in the following terms:—“ Auckland city, situated at the northern extremity of New Zealand, will be. owing to its favourable geographical situation; the focal point of the closing of the great aerial circle of the British Empire Airways, besides being on one of the main, routes of the Pan-American Pacific Airways. In addition to this. Nature has provided it with a firstclass natural flying-boat base exceeding an area of tv/o square miles of sheltered water, suitable for the largest flying boats. It lies in Waitemata harbour, south of Hangitoto Island and the mainland, well away from the harbour’s usual main navigation channels, and reasonably close to the city. For these: reasons Auckland will probably be the rendezvous of the large transocean flying boats, other parts of the Dominion being probably served by the New Zealand ordinary local airways, or flying boats that may be required for specific services, only connected with the linking up of the neighbouring Pacific Islands both within and without the Dominion, as the development of commercial aviation will inevitably demand within the next five or 10 years. The Lyttelton Site

Coming to the Christchurch proposals, the report proceeds to examine the two suggested sites in relation to the basic requirements, based o.n the Australian standard as being the most complete, to ascertain thereby their fitness or otherwise for a seadrome site. Dealing with Lyttelton Harbour, the basic requirements are set down as under:—(a) A water area between two and three square miles, on alternative sites, on either side of Quail Island, one involving extensive dredging, and the other shag reef removal with less dredging, (b) Physical features, old crater, readily discernible from the air. (c) Situation— Road, Christchurch, Sumner, Lyttelton, main highway nine to 13 miles, narrow and steep grades up to one in nine over Evans Pass. Railway, 6| miles, with single track tunnel through the Port Hills. Shipping— Lyttelton is the seaport of Canterbury and Christchurch. (d) Equipment— Does not need consideration at the present sta?e. Dealing with the Lyttelton site in relation to the Australian standard, the report makes the following observations:—(a) An alighting and tak-ing-off area is available, (b) In regard to obstructions, there are rbag reef.and beacons, and insufficient depth of water, and the site is shut in by abrupt, high hills. (c) The wave range is known to be as much as four feet, whereas 2} feet is the maximum advisable, (d) A mooring area could be made available by extensive dredging and breakwater protection. (e* In regard to the depth of water at low water, ordinary spring tides, thatat site A is from one to nine feet, and site B from eight to 16 feet, (f) The tidal currents’ velocity is negligible. <g) Swinging room could be made available by dredging. Additional considerations:—(a) No land is available for buildings without reclamation, (b) In regard to denudation and silting, dredging would be necessary to maintain increased depth. (c) Fogs are experienced about eight days a year. (d) JThe noise might possibly be a serious nuisance to Lyttelton and Governor’s Bay residents. (e) No land is available for shore facilities, and a suitable area would have to be reclaimed by dredged material. In a special note. It is stated that the topographical configuration of the narrow, deep, confined crater site, surrounded on three sides by high volcanic hiuS, presents grave complexities from an airman’s navigational viewpoint. This is further complicated by the massif of Quail Island at the upper end of the harbour, and shipping at the lower end. with southerlies’ sweeping over Gebbie’s Pass, and the exposure of the harbour entrance to diirect easterlies, creating an unfavourable wave range. Estuary Site Preferable

Traversing the Avon and Heathcote estuary site, the report has the following to Say in regard to the basic re-

quirements;—(a) A water area is available up to about two square miles; (b) the physical features are readily discernible from the air; (c) in point of situation the site is five to

six miles by highway from Cathedral square, tramways are available, and

railway communication could be inexpensively restored to Ferrymead

wharf as originally .laid; (d) the matter of equipment does not need consideration at the present stage. Dealing with the site in relation to the; Australian standard, the following observations occur;—(a) An alighting and; taking-off area is available with extensive dredging; (b) in point of

obstructions there is insufficient depth

of water, with electric light and power lines along the main road on the Sum-ner-Redcliffs side; (c) the wave range is satisfactory, being about 2$ feet; (d) a mooring area would be available with extensive dredging; (e) in regard to depth of water, at low water, ordinary spring tides, the site is ex-

posed. excepting the deep water channels from one .to six feet deep and of

very limited width and water area at low tide; (f) water velocities—river currents and tidal currents moderate; (g) springing room would be made available by extensive dredging. Additional considerations: —la) Some 200

acres of land should be purchased for buildings; Cb) denudation and silting—present and considerable, needs Investigation; <c) fogs, about 10 days a year; (a> the noise might possibly be a serious- nuisance to residents in the

vicinity; - <e) land for shore facilities is available lor purchase. Commenting on the above, the report said: /'This site is only protected from the Sea hr the narrow sand spit on the Pleasant Point side and is therefore exposed to the northerlies and easierJies»,but sheltered from the southerlie*. The many spurs of Mount Pleasant, l<Bf feet nigh, are in most places only separated from the water’s edge at higb water, ordinary spring tide, by

the Christchurch - Sumner -I# road following the estuary 4M> Possibilities at EUeene* After comparing the two gM summing up in favour of tiff # the report refers to the possWW the Akaroa and Lake EUesm(s» Referring to the Akaroa site,* this has somewhat similar fH istics to Lyttelton, being an d| canic crater, but is as a rule tcfl Shipping. The water area wad most likely deeper and thus fti| tensive and expensive dredgiQfLj however, some 52 miles distantly from Christchurch, the routed very tortuous, • with long and 1 grades over the Hilltop between: river and Akaroa. It is some by air in a land aeroplane, 90 could he used. The wave range H it is thought, exceed 21 would, under certain weather ig)| conditions, perhaps be as mjjfe Lyttelton, so would be prohflww “Lake .Ellesmere, however"*] the report, “has distinct and {M possibilities. It has an arwyß 60 square miles, and its nawM shore comes closely to radius from the ChristchaK# centre, with excellent main munication. It is understood .’P| maximum depth of water is about six feet, so that it is PeM suitable for light float could be used by light draagW;| boats with caution. There WM an area of two squares milasjg depth available, so that it eowH ably be dredged the extra foWyl 10 feet much less expenstfUß either Lyttelton or the (M| the dredged lake bottom wfiPH haps be more stable, wh*jt»a mean no maintenance dreflgjHßß wave range is not known 4H have to he ascertained, in thought it will be about 2» W Little River-Christchurch skirts the north-western iMH| lake, and there are railway H Motukamw Knttnn» ad WM