NAVIGATION LIGHTS

Greymouth Evening Star, 9 March 1939, Page 11

NAVIGATION LIGHTS

PORT OF GREYMOUTH NEW SYSTEM ADOPTED A new system of navigation beacons for the harbour was approved at a meeting of the Greymouth Harbour Board last evening, on the recommendation oi the Engineer (Mr. D. C. Milne), who presented the following comprehensive report on the subject:— "It was suggested in my previous report that while it was unlikely that there was any direct interference by neon signs with the beacon lines, and, therefore, no danger of shipmasters mistaking a neon sign for a beacon Ik-lit, it was probable that the general tiaro from the lights in the town rendered it difficult to distinguish the navigation lights. The recent inspection which was carried out at night off the harbour entrance confirmed this opinion, and it was revealed that the chief source of trouble were the lights in tho marshalling yard, and also one of tho street lights at the- corner of Arney Street and Gresson Street, .vhich is located near the line of the green beacons, and which by its relative brightness decreased the power of the beacon lights. The necessary adjustments will be made to these lights, and also to certain of the neon signs which are visible from the sea. Although these alterations will very materially improve the position, 1 am of the opinion that in order to provide a more effective system of navigation beacons, it. will be necessary also to increase the power of the beacon lights, and the time appears opportune to introduce a new arrangement of navigation beacons.

“The present system of navigation beacons has been in operation for over 50 years, and consists of two lines, one of which is marked by a pair of red beacons, and the other by a. pair of green beacons. The function of the latter pair of beacons is to guide vessels along tho channel, from the harbour entrance to the wharf.

“The red beacons were originally designed to guide vessels across the. bar, and, in the early days of the port, they played an important and necessary part in the navigation of the harbour entrance. At that time, the location of the deep water channel across the bar varied with the movement of shoal banks at the entrance. It was necessary, therefore, to alter, frequently, the line of tlie red beacons, and, to affect this, the front beacon was mounted on a platform, which enabled the beacon to be rapidly moved into any desired position to conform with the variation in location of the navigation channel. With the extension of the breakwater seawards, however the deep water channel became stabilised, the formation of shoal banks ceased, and the bar assumed its present form of a more or less uniform bank, extending between the heads of the breakwater. As a result of the fixation of the entrance channel, the original function of the red beacons disappeared, and it is difficult to understand on what grounds their retention was justified. Instead of being removed, however, the front red beacon was fixed in such a position that the red beacon line intersects the line of the green beacons on the bar. The defects of such an arrangement are obvious and have on previous occasions been pointed out to the Board. Tho chief objections are as follows: — “(1). The beacon lines converge as they approach the bar and at their point, of intersection; where accurate and reliable marine survey data is more essential than -at any other point on the entrance channel, ship masters are given no indication of the width of channel available for navigation. (2). In navigating the bar on the lines of red beacons vessels enitering or leaving the harbour must , swing from one beacon line on to the i other, and, in performing this manoeuvre, the vessel follows an indefinite course over a portion of the channel, which is not covered by any system of soundings. “The navigation of bar harbours in general requires the exercise of unusual vigilance on the part of shipmasters, and, so far as Greymouth is concerned, the problem is still furthei complicated by the uncertainty of the sea conditions prevailing at the entrance. It is, therefore, desirable in the interests of safety, that the beacon system should be such as to provide a reasonable width of navigation channel, and that it should bo as simple as is consistent with practical requirements Tho present arrangement ol beacons does not fulfil either of these conditions, and it has the land imentill defect tlicit, at the most critical point in the navigation of the harbour entrance, vessels must swing from one beacon line on to the other, and so add further to the difficulties of shipmasters.

CHANGES DETAILED. “The proposed new system of navigation beacons is shown on the plan which- accompanies this report. The red beacons have been eliminated, and the green beacon line has been adopted for the navigation of both the bar and the river. In order to provide a definite navigable width of channel on the bar, a cross arm carrying two black diamond shaped beacons has been added to the front green beacon. The effect of placing each of these subsidiary beacons in alignment with the rear green beacon win be to produce two lines which will diverge as the bar is approached from the river, and the object of these additional lines will be to mark definitely the limits of the navigable channel. The width of the channel on the bar has been fixed at 150 feet, and although a greater navigable width would be desirable it is not to be recommended on account of the necessity of providing adequate clearance on the toes o* thebreakwaters. , I “In sounding the bar three lines oi | soundings are taken—one on the! centre line and one on each ot t.hej channel limit, lines. The least depth •dirained would then be adopted as the •hrth available for navigation and ( i.his would enable, shipmasters to manoeuvre their vessels confidence anywhere within the limits of the surveyed navigable channel. I would suggest that this system be adopted, and that the power of the, ”.reen beacons be increased by the substitution of neon lights for the green -loctric. lights at present in use: the latter would, however, be retained and would be available in the event of failure at any time of the main lights. The channel limit lines will be marked by red neon tubes placed on each of the diamond shaped beacons, and will .enable shipmasters to determine, ac-

curately, the position o£ tho entrance of the channel, when navigating the bar at night. lam of the opinion that (ho adoption of the proposed system of beacons would form an important contribution to increasing the salety factor for shipping frequenting the port, and the Harbourmaster concurs m this. 1 would recommend, therefore, that the Board proceed immediately with the new installation. A plan of the proposed system accompanied the report. The Chairman '(Mr. J. Ryall) moved that the report, be received, and the recommendations given effect, to. The motion was seconded by Mr. Kent.

Mr. J. A. Murdoch suggested that unless the Engineer had good reason against the proposal, that the masters of three of the largest ships trading to tlie port be consulted in the matter, and their recommendations taken in writing. The men in charge of the ships should have a right, to make suggestions. ' Mr. J. B. Kent contended that such a course would show a lack of confidence in the Engineer and the Harbourmaster, both of whom were fully qualified men. Those officers thought the change necessary, and the Board should proceed with it immediately. It, was not necessary to go to the masters of vessels. Mr. P. J. McLean said - he thought tho matter had been thoroughly investigated, and the Board should be guided by the Engineer and the Harbourmaster. it would probably be difficult to get the masters to agree on a recommendation. Mr. J. Smeaton agreed that the Board should adopt the recommendations. If there were an accident due to the system of lighting the Board and its officers would be called to boot, not the mariners. To Mr. A. 11. McKane, the Secretary (Mr. W. B. Gilbert) said that the new system would have to be gazetted. The E Harbourmaster (Captain H. Moar) said he would soon get three masters to agree to the scheme, if the Board wanted them. Mr. McKane said they might get three to agree, and others might not agree. The motion, receiving the report and adopting the recommendations, was carried unanimously. On the motion of Messrs. McKane and McLean, it was decided that copies of the Engineer's report on the scheme lie circulated among members; also that members receive a copy of the Engineer's ordinary monthly report prior to the meeting night.