JULY 5.] THE NEW ZEALAND GAZETTE. 2741

Notice to Mariners.—No. 59 of 1917.

Marine Department,
Wellington, N.Z., 3rd July, 1917.

THE following Notices to Mariners, which have been received from the Hydrographic Office, London, the Board of Trade, London, the Hydrographic Office, Washington, and the Harbours and Marine Board Offices, Adelaide, are published for general information.

GEORGE ALLPORT,
Secretary.

BRITISH ISLANDS.

INTENDED INTRODUCTION OF SUMMER TIME.

Period of alteration.—From 2.0 a.m. 8th April to 2.0 a.m. 17th September, 1917.

1. During the above period British Summer Time, which is one hour in advance of Greenwich Mean Time, will be kept in the British Islands.

2. The clock time of all time-signals, with the undermentioned exception, will be one hour later than the time shown in the Admiralty List of Time-signals under the column “Standard Time”; the Greenwich mean time of the time-signals remaining the same as shown in Admiralty Publications.

The exception referred to above is the time-gun at Edinburgh Castle, which will be fired at noon G.M.T., corresponding to 1 h. 00 m. 00 s. British Summer Time.

3. In the Admiralty Tide Tables, Part I, 1917, and Part II, 1916, which is still current, full information is given as to the time used.

In all cases in which the time shown by the clock differs from that used in the Tide Tables, the difference must be applied to the time of the tide as obtained from the Tide Tables.

Note.—Greenwich mean time should invariably be used, both in Great Britain and Ireland, in all tidal records kept for permanent reference.

4. It should be noted that the change in time also temporarily affects certain Admiralty Sailing Directions and Charts, &c., as well as the tables showing the duration of “Official Night” embodied in the Public Traffic Regulations for various Defended Ports.

CHANNEL ISLANDS.

JERSEY, ST. HELIER APPROACH.—LA GR VE D’AZETTE LIGHT.—ALTERATION IN CHARACTER.

Position.—Near the White Patch. Lat. 49° 10¼′ N., long. 2° 5′ W.

New abridged description.—Lt. F. gn., 75 ft.

Alteration.—The character of the light has been altered from occulting white to fixed green.

NORTH ATLANTIC OCEAN.

DERELICT REPORTED.

Date sighted.—On the 27th April, 1917.

Position.—Lat. 52° 8′ N., long. 15° 6′ W.

Description.—Derelict Danish schooner.

Caution.—This derelict constitutes a danger to navigation.

OREGON.

COLUMBIA RIVER APPROACH.—LIGHT-VESSEL MOVED.

On 2nd May, 1917, Columbia River light-vessel was moved and re-established, in about 35 fathoms of water, on the main channel range line, about 1⅓ miles 180° from her former position.

Approx. position : Lat. 46° 10′ 45″ N., long. 124° 10′ 35″ W.

COLUMBIA RIVER ENTRANCE.—MAIN CHANNEL.—DEPTHS.

From a survey of the mouth of the Columbia River made by the U.S. Engineers in April, 1917, it appears that there is a least depth of 34 ft. on the main channel range line on the bearings—

North Head Lighthouse .. .. 19° 30′
Tank on South Jetty .. .. 92° 30′

About 150 yards to the eastward of this 34 ft. spot the least depth is 33 ft., while at the same distance to the westward it is 37 ft.

UNITED STATES.

EAST COAST.—NEW YORK HARBOUR.—CLOSED BY NIGHT.—TRAFFIC REGULATIONS.

New York Harbour is closed to all traffic between sunset and sunrise; during the day all traffic must pass through a gate 500 ft. in width off the Staten Isl. shore of the Narrows. 23rd April, 1917.

NEW YORK UPPER BAY.—THE NARROWS.—CAUTION.—A spar lt.-buoy numbered “12AAA,” exh. an occ. red lt., vis. 5 secs., ecl. 5 secs., is est. in 40° 36¾′ N., 74° 3½′ W., on the wrn. side of the Narrows, 5 cables 344° (N. 5° W. mag.) from Fort Wadsworth Lt.-h.

Caution.—The following cautionary note with regard to vessels and boats passing through the Narrows is to be charted : “All vessels and boats inward or outward bound to or from N.Y. Harbour must pass westward of Lt.-buoy No. 12AAA.” May.

The Battery.—A fog-bell, sounding gps. of 4 strokes at intervals of 10 secs., is est. on Pier A, the wrn.-most pier of the U.S. Barge Office dock. March.

NEW YORK HARB. APPROACHES.—FIRE ISL. LT.-V.—RADIO DIST. DETERMINING APPARATUS INSTALLED.—The attention of all ships nav. the approaches to New York Harb. is invited to the recent installation on Fire Isl. Lt.-V. of a combined radio and submerged sound sig. transmitter which determines the receiving ship’s dist. from the Lt.-V. (Call letters, NLS; station, 40° 28′ 40″ N., 73° 11′ 26″ W.) This apparatus will be in operation during fog, mist, rain, or falling snow. The range of this apparatus is limited to the receiving range of the submarine bell receiving equipment employed on shipboard, and in all practical cases this is within 6 or 7 miles. The submarine bell strikes six strokes, pause, then eight strokes once every 38 secs. Beginning shortly after the first stroke of the “6” submarine character, about ½ sec., the ship emits a series of radio sigs. In order to determine the dist. of a ship from the Lt.-V. it is necessary to count each of these radio dots until the first stroke of the six submarine sigs. is received. The number of dots thus determined gives the dist. in half sea miles from the Lt.-V.

Example.—(a.) Eleven radio dots are received before the first stroke of the bell; the dist. is 11/2 or 5½ miles. (b.) Four radio dots are received; the first submarine bell sig. appearing midway between the fourth and fifth radio sig.; the total number of radio sigs. received is 4½, and the dist. is 4½ divided by 2, or 2¼ miles. The most convenient method of receiving these sigs. is to have one receiver connected to radio and the other receiver connected to submarine bell detector, thereby connecting one ear to radio sigs. and the other to submarine sigs. These sigs. will also be furnished in clear weather when requested to do so by radio. It is requested that all passing vessels equipped with submarine sig. receiving apparatus familiarize themselves with this apparatus and report success obtained to the Hydrographic Office. Wave-length used is 600 metres. Watches are stood as follows: (1) Continuously during thick weather; (2) during clear weather, first 15 mins. of every hour from 8 a.m. to 9.15 p.m. Although this station has proved accurate on test, the apparatus is in an exper. stage, and too much reliance should not be placed on it until its worth has been proved under service conditions. April.

LONG ISLAND.—FIRE ISL. RADIO STATION.—DIRECTION TRANSMITTER INSTALLED.—A radio direction transmitter has recently been installed at the United States naval radio station, Fire Isl. (call letters NAG), and from 15th Jan., 1917, radio direction transmitting sigs. will be made at this station. The station will transmit during fog, mist, rain, or falling snow semi-hourly for 5 mins. (from 0 to 5 mins. and from 30 to 35 mins.), and at such other times as requested by passing vessels. The wave-length employed is 450 metres for direction transmitting and 600 metres for communication. The purpose of this directional transmitter is to enable ships to determine their true bearing from the transmitting station, but it must be understood that this apparatus is in an exper. stage and that bearings obtained are subject to errors of several degrees. All vessels fitted with radio apparatus are requested to co-operate with the Department in order that the usefulness of this apparatus as an aid to nav. may be determined. The station, when transmitting on the compass antenna, emits a series of 32 dots whose intensity varies at the receiving station due to its bearing from the compass set. Each dot of this series represents a point of the compass. The beginning of the series is indic. by the letter B (— - - -) after which each dot of the series represents a point (11° 15′) in a clockwise direction from true north. It will be noted during operation that at times weak sigs. will fall directly between two or three numbers—i.e., two or three sigs. will appear. have the same intensity. By the following procedure it is possible to closely determine the position of the desired weak sig. :—First: As soon as the letter “B” is transmitted, start recording marks for each radio sig. received, and continue until the letter “B” is again received. The length of these marks should be somewhat in proportion to the strength of the received sigs. Second: If there is a gap in the series of received sigs., dots should be recorded until the next audible sig. is received where marks are continued corresponding to each radio sig. until the letter “B”