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ro] Epo {ix ' pay ‘ —— sande a ene denn ff Rac ennen mated The Light-Ships and Gas_Buoys. THE MARINE REVIEW :—In reply to your request of the 21st inst. for information relative to the light ships and gas buoys I beg to say that, pending action by congress, the board has not as yet made final disposition with regard to these mat- ters, and the preliminary arrangements are therefore subject to . modification when the necessary appropriations are made. ‘The accompanying print shows the general design for light ships, submitted to the board as a basis for estimate. ‘The vessels, as proposed, are 1oo feet long over all, 20 feet wide, and 14 feet deep, drawing 9 feetof water with 5 feet of freeboard. They are fur- nished with propelling power, having a marine boiler 5% feet by 9 feet, a cylinder, say 14x 16 in.,and a 5 or 5% foot wheel. They will thus be able to proceed direct to their stations in the spring _. and return to harbor in the fall, remaining out as long as there _.. is any occasion tor their seryice, and taking off the keepers of » the isolated stations who now have to get away while they can, .. often before the latest vessels are past. In case of a particularly . yiolent tempest, the machinery can relieve the strain on the .. moorings, and in urgent cases of need or disaster in the vicinity, ..,. the light vessels can do duty as life saving stations. An auxiliary boiler and steam hoist will be furnished, to _ heat the vessel, keep the main boiler hot, and hoist the lights or run a dynamo as may be determined. ‘The lights will be on - one or both masts, at an elevation of 45 feet above the lake and . will be visible in clear weather for 10 or 15 miles. ‘The steam fog-whistle will be 10 inch, the same as used on the shore sta- tions. For moorings, heavy anchors ora 1o0-ton casting will be set on the reef with a range of extra heavy steel cable attached. _To this, following the device of Commander Ludlow for anchor- ing buoys on the Pacific coast, it is proposed to connect a double wire rope mooring, one right and one left-hand twist, securely seized together at short intervals. This makes a light and powerful mooring. Inleaving station,the light ship will hoistin the wire cable, unshackle it from the steel range, and buoy the end for recovery in the spring, without disturbing the heavy casting. The ships, as proposed, are strongly built of oak as being, for vessels of these dimensions, cheaper and stiffer than metal. A _ steel sheathing, say 4 feet wide along the water line, will protect them from ice, and with care they will be good for 20 years. The coal bunkers will hold 30 to 40 tons, which, as the average annual consumption by a steam fog-signal is 18 tons, will be an ample supply for service and movement. ‘The cost of each complete, exclusive of the special light-house equipment, will be about $15,000, and including the illuminating apparatus and a season’s supply of stores on board, about $2,500 in addition. If built of metal, the cost would be about 25 or 30 per cent. more. ‘The crew will consist of four men—a keeper capable of running the machinery, an assistant keeper, and two hands. ‘The vessels can rendezvous for the winter at Beaver island. Harbor Springs, Scammon’s harbor, or Cheboygan, and refit for the next season. Pi +4 fw Ne ere -\“ of ' ew Sk cade daa e sod Sethe Gas-light buoys have been in use for many years in Holland, Germany, France, England, and in this country, and Canada has made good use of them on the St. Lawrence river. They do valuable service as minor aids, mark- ing shoals adjacent to channels, and turning points in narrow navigations, where fixed lights are unnecessary or too costly, and in marking wrecks and temporary obstructions. There are several localities on the lakes where gas buoys would do valuable service, for ex- ample, at some points in the Detroit, St. Clair and St. Mary’s river, the shoals adjacent to the.track of vessels at the lower end of Lake Huron, numerous reefs in the vicinity of the ==aStraits, such as the Graham shoals, the shoals ~ south of Fox Island, Drisco and Whale’s Back in Green bay, and several lying in or near the track of vessels through the Green bay passages. The shape of the buoy is not material so long as it is properly adapted to the locality where it is to be used. The form now in use for the ordinary can buoy is good. To stand the necessary compression, the gas should be specially prepared, preferably from petroleum, and is stored in the body of the buoy from a reservoir on the tender; com- pressed to 5 or 6 atmospheres, say 75 to go lbs. pressure. A pipe leads from the buoy toa lantern 6 to 8 feet above the water, properly protected from the wind andsea. An automatic regulator main- tains a constant pressure of gas at the burner, compensating the gradual reduction of pressure in the buoy as the gas is used. The light will burn for 30 to 120 days, according to the size of the buoy, at the rate of 16 or 17 cubic feet in 24 hours. Being in the water and adjacent to the track of vessels, gas buoys are \ exposed to the same accidents as others, and occasionally fail or — are injured, but the Canadian experience has been that: while they cannot be as certainly relied upon as a shore light, they are eminently useful and the navigators would be loath to lose them — from points where they have been established. It is evident that for economy, gas buoys should be established, not at a few widely separated points, but in localities where several are re- quired and where the same apparatus for procuring and deliver- ing the gas can be used for all. It is also evident that for such localities as Gray’s reef, White shoal and Simmon’s reef, the © power and range of the gas buoys are quite inadequate to the needs of navigation, With the numerous minor points to be — marked in and near the-straits of Mackinac, it will no doubt: be found advisable, if gas buoys are to be used, to establish at © some conveniently central point, a small plant for the manufac- - ture, etc., of the gas, and the service of a small tender to look © after them. ‘The expense of this service will prove to be more — than compensated by the reduced risks and losses. | ; WILLIAM LupLow. oe