Special signals for surveying vessels of the U.S. Coast and Geodetic Survey employed in hydrographic surveying have been prescribed as follows: By day, a surveying vessel under way and employed in hydrographic surveying, may carry in a vertical line, one over the other, not less than 6 feet apart where they can best be seen, three shapes not less than 2 feet in diameter of which the highest and lowest shall be globular in shape and green in color and the middle one diamond in shape and white. By night, a surveying vessel under way and employed in hydrographic surveying, shall carry the regular lights prescribed by the Rules of the Road. When at anchor in a fairway and engaged on surveying operations, a survey vessel shall display during the daytime two black balls in a vertical line and 6 feet apart. At night two red lights shall be displayed in the same manner. In the case of a small vessel the distance between the balls and between the lights may be reduced to 3 feet if necessary. Such vessels, when at anchor in a fairway on surveying operations, shall have at hand and show if necessary in order to attract attention a flare-up light in addition to the lights which are, by this regulation, required to be carried. Anchorages are numerous, except on the northerly and easterly sides of the islands, the first requirement under ordinary conditions being shelter from the trade winds. During kona weather most of the anchorages on the southerly and westerly sides of the islands are unsafe. Harbors and ports. The only harbors which offer protection in all weather are Honolulu, Hilo, Kahului, and Nawiliwili on the islands of Oahu, Hawaii, Maui, and Kauai, respectively. There are numerous other ports and landings with protection from certain directions only. Harbor control.-A harbor master is appointed for each of the harbors of Honolulu, Hilo, and Kahului, and they have charge of the anchorage and berthing of vessels in their respective harbors. For harbor regulations see Appendix. There are local officials who are charged with the duties of harbor masters at various other ports. Towboats.-Young Bros. and the Matson Navigation Co. each operate seagoing towboats out of Honolulu. Small gasoline towboats are available at the following ports: Hilo, Kahului, Ahukini, and Nawiliwili. Supplies. Provisions, ice, lumber, and ship-chandler's stores can be obtained at Honolulu, Hilo, and Kahului. Supplies in limited amounts can be obtained at many other ports and landings. Water can be conveniently obtained at the wharves at Honolulu, Hilo, Kahului, Nawiliwili, and Ahukini. Water may also be obtained at other ports and landings. Coal, fuel oil, and lubricating oils can be obtained at Honolulu, Hilo, and Kahului. Gasoline may be had at most of the landings. Repairs. There are machine shops at Honolulu, Hilo, and Kahului, and ordinary repairs to machinery can be made. The railroad and plantation shops on Kauai can handle some emergency repairs. There are three floating drydocks at Honolulu having keelblock lengths of 352 feet, 165 feet, and 53 feet. The large dock has a dead-weight capacity of 4,500 tons and has lifted vessels over 400 feet long. Wharves and at which vessels can lie to discharge and load are located at Honolulu, Hilo, Kahului, Ahukini, Nawiliwili, Lahaina (Mala), Hana, and Kaunakakai; the last three are for smaller vessels only. At the other ports freight is handled either by lighters or wire cable. Railroads.-A railroad skirts the shores of Oahu westward from Honolulu along the southwesterly and northwesterly sides and halfway down the northeasterly side. Another extends northwestward from Honolulu about one half the way across the island. Railroads extend northwestward, southward, and southeastward from Hilo. Railroads also extend a short distance northeastward, southward, and northwestward from Kahului. There are other short railroad lines at various places, practically all of which are for plantation use only. Highways.-There are good highways in many parts of the islands, and automobiles can be obtained at most of the towns. Communication with San Francisco, Vancouver, Auckland, Sydney, Manila, Yokohama, and Hong Kong may be had by several regular lines of steamers which touch at Honolulu. There is also a line of steamers to Seattle and Tacoma and another to the east coast of the United States via the Panama Canal. An excellent interisland service of both steamers and airplanes is maintained. Cable and telephone. There is communication by cable to San Francisco and to Manila via Midway and Guam, and by radiotelegraph between the islands and with the mainland of the United States and with the Orient. There is good telephone service on all of the large islands. Radiotelephone service is maintained between the islands and with the mainland of the United States. RADIO SERVICE The supervision of radio communication in the United States, including Alaska and the Hawaiian Islands, is controlled by the Federal Radio Commission. The following publications may be obtained from the Superintendent of Documents, Government Printing Office, Washington, D.C. Commercial and Government Radio Stations of the United States (includes shore and ship stations). Radio Service Bulletin (issued monthly to supplement the above publication; contains amendments and other information). Amateur Radio Stations of the United States. Time signals.-In connection with the service over the land telegraph wires, time signals by radio are sent daily from certain United States naval radio stations. American radio stations use a distinctive type of radio time signals known as The United States System. The total duration of signal is 5 minutes. Preparatory or warning signals are omitted. The duration has been reduced to 3 minutes before the hour at all stations dependent upon commercially controlled telegraph wires. This change does not alter the existing time-signal code, since the last 3 minutes of the code are still used. The signal consists of the transmission of a dot (.) for every second, omitting the twenty-ninth, fifty-first, fifty-sixth, fifty-seventh, fifty-eighth, and fifty-ninth second during the first minute; in the second minute the twenty-ninth, fifty-second, fifty-sixth, fiftyseventh, fifty-eight, and fifty-ninth second will be omitted; in the third minute the twenty-ninth, fifty-third, fifty-sixth, fifty-seventh, fifty-eighth, and fifty-ninth second will be omitted; in the fourth minute the twenty-ninth, fifty-fourth, fifty-sixth, fifty-seventh, fiftyeighth, and fifty-ninth second will be omitted; in the fifth minute the twenty-ninth, fifty-first, fifty-second, fifty-third, fifty-fourth, fifty-fifth, fifty-sixth, fifty-seventh, fifty-eighth, and fifty-ninth second will be omitted; at the sixtieth second a 1-second dash (-) will be sent, the beginning of which is the time signal. This is followed by the letters VA. In the event of an error occurring in the signal, another time signal will be transmitted one hour later on the same frequency. Hydrographic information, weather reports, and other information of benefit to shipping are sent out from these and other naval radio stations along the coast. Time signals are sent out from naval radio stations both at San Francisco and Honolulu. For details as to schedules, frequencies, etc., see Hydrographic Office Publication No. 205. RADIOBEACONS The U.S. Lighthouse Service operates radiobeacons in the Hawaiian Islands at the following places: Makapuu Point Light Kilauea Point Light For details as to frequencies, geographic positions, signals, and thick and clear weather transmission, see Light Lists of the Lighthouse Service or Hydrographic Office Publication No. 205. These radiobeacons are intended for the use of vessels equipped with radiocompasses. While the use of radiobeacons should not lead a mariner to neglect other precautions, such as the use of the lead, etc., during thick weather, the bearings will greatly reduce the dangers incident to navigation in the fog. The bearing of the radiobeacon may be determined with an accuracy of approximately 2° and at distances considerably in excess of the range of visibility of the most powerful coast lights. The apparatus is simple and may be operated by the navigator without the assistance of a radio operator or without the knowledge of the telegraph code. The radio direction finding apparatus consists of a radio receiving set, similar in operation to those used for radio telegraph or telephone reception, and a rotatable coil of wire in place of the usual antenna. By rotating the coil, the intensity of the signal received from the transmitting station is made to vary, and by noting the position of the coil when the signal is heard at its minimum intensity, the bearing of the transmitting station is readily obtained. It is important to note that the bearing of an incoming radio wave is subject to errors not unlike the deviation of the magnetic compass. Those using radio direction finding aboard ship are cautioned to bear these errors in mind and to keep the radiocompass calibrated at all times. This may be done during clear weather by comparing the bearing obtained with the radiocompass with the bearing as obtained by visual methods in general use. All radio bearings are subject to what is called "night effect", a variable error sometimes experienced near nightfall and sunrise. The uncertainty due to this cause may be lessened by taking repeated radio bearings. The signals from the radiobeacons have definite characteristics for identifying the station, and bearings may be obtained with even greater facility than sight bearings on visible objects. A general description of this method of navigation and the instruments required is given in Lighthouse Service publication Radiobeacons and Radiobeacon Navigation, which may be obtained from the Superintendent of Documents, Washington, D.C., price 15 cents. CONVERSION OF RADIO BEARINGS TO MERCATOR BEARINGS The increasing use of radio directional bearings for locations of ships' positions at sea, especially during foggy weather, has made it particularly desirable to be able to apply these radio bearings taken on shipboard or sent out by the shore stations directly to the nautical chart. These radio bearings are the bearings of the great circles passing through the radio stations and the ship, and unless in the plane of the Equator or of a meridian, would be represented on a Mercator chart as curved lines. Obviously it is impracticable for a navigator to plot such lines on his chart, so it is necessary to apply a correction to a radio bearing to convert it into a Mercator bearing; that is, the bearing of a straight line on a Mercator chart laid off from the sending station and passing through the receiving station. On page 9 is given a table of corrections for the conversion of a radio bearing into a Mercator bearing. It is sufficiently accurate for practical purposes for distances up to 1,000 miles. The only data required are the latitudes and longitudes of the radiobeacons and of the ship by dead reckoning. The latter is scaled from the chart, and the former either scaled from the chart or taken from the list of radiobeacons found in the light list or Hydrographic Office Publication No. 205. The table is entered with the difference of longitude in degrees between the ship and the station (the nearest tabulated value being used), and opposite the middle latitude between the ship and station, the correction to be applied is read. When the bearings are taken from the ship, the sign of the correction (bearings read clockwise from the north) will be as follows: In north latitude, the minus sign is used when the ship is east of the radiobeacon and the plus sign is used when the ship is west of the radiobeacon. In south latitude, the plus sign is used when the ship is east of the radiobeacon, and the minus sign is used when the ship is west of the radiobeacon. To facilitate plotting, 180° should be added to the corrected bearing, and the result plotted from the radiobeacon. Should the position by dead reckoning differ greatly from the true position of the ship as determined by plotting the corrected radio bearings, a retrial should be made, using the new value as the position of the ship. Example. A ship in latitude 26°00′ N., longitude 157°00′ W., by dead reckoning, obtains a radio bearing of 236° true on the radio CONVERSION OF BEARINGS 9 beacon at Makapuu Lighthouse located in latitude 21°19′ N., and longitude 157°39′ W. Radiobeacon station latitude. Dead-reckoning position of ship- Middle latitude___ 21 19 N., long. 157 39 W. 23 40 Difference 7 39 Entering the table with difference of longitude equals 72°, which is the nearest tabulated value, and opposite 24° middle latitude, the correction of 1.5° is read. The ship being east of the radiobeacon, the correction is minus. The Mercator bearing will then be 236° -1.5°=234.5°. To facilitate plotting, add 180° and plot from the position of the radiobeacon, thus: 234.5°+180°=414.5° or 54.5°, which is the true bearing to be laid off from the position of the radiobeacon. If the bearing is from a shore station, the signs will be reversed to those given above. Table of corrections [Difference of longitude in degrees 1° 12° 2° 212° 3° 32° 4° 42° 5° 52° 6° 62° 7° 72° 8° 82° 9° 9° 10° Mid. L. |