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MARINE REVIEW. oe | 13 How to Lay Down a Ship. "The drawing-boards are of very large size, as the designs are got out to a scale of 4 in. to a foot; and as many of the vessels are from 500 ft. to 600 ft. long, the drawings are of great length. The boards are stiffened by a longitudinal rib at the back, and the T squares are used across the boards instead of longitudinally. A rough sketch de- sign is first got out, thisis then sent into the model room, where a half model of the hull is then made. This is fixed to a board and sent back into the drawing office, and there a draughtsman sets off the positions of the frames upon the back board, and then in the model shop these lines are scribed vertically on the model. The whole of the lines rep- resenting deck and plating are then marked off upon the wooden model, and the draughtsman proceeds to set off the plates in such a way as to break joint as much as possible with others in adjoining strakes. AIl the models are made to a scale of 4 in. to1 ft. Designs are then pre- pared, showing how the various strakes run, and each strake is lettered and marked 'in' or 'out,' as the case may be. The whole of the hull is built of mild steel, and the dimensions for thickness are always given in twentieths of an inch, whereas for wrought iron dimensions are given in sixteenths. In examining a set of drawings which were in hand, the garboard strake plates were figured 21-20, the sliper strake 21-20, andl the bilge 16-20 to 17-20, while the frames were 7 in. by 34 in. by 11-20 in.; the longer plates were about 28 ft. The whole of the original drawings are stretched and glued to the drawing-boards, and the shop-tracings are made on cloth and colored and fully dimensioned. "The mould loft is one of the most important parts of the works. Here the floor is well laid, and upon it are fixed immense boards specially made for each vessel. The drawings, prepared in the draw- ing office to a scale of { in. to a foot, are brought here, and the whole of the lines representing the curves of the frames and plates are laid . down full size. At first the lines are merely chalked out with the'aid of long pliable straight edges, and then these lines are cut into the wood itself by hand with a knife. Each of the various sweeps is fig- ured so as to correspond with the drawing, these processes being known as 'sereeying.' The floor is thus covered with a maze of curves and straight lines, and when complete the whole floor is taken up and carried into the plating shed, where it is pieced together again. We now reach the platers' shop, and here will be seen the screeving boards carefully laid down on the floor. Upon the surface of the boards are screwed pieces of half-round iron, so that the surface may not be burnt when hot templates are tried on. A template consisting of bar iron about 2 in. wide by 4 in. thick is now bent to fit each one of the curves on the screeye board, and these templates are fixed upon the large face plates and the frame channels are bent to fit them. A gang of special smiths is kept for this work, the holes in the frames having all been drilled before they go into the furnace. Long channel irons are heated in special furnaces with six fires down the sides, so as to obtain an equable heat over the whole length of the frames."--The Engineer, London. Lake Navigation Forty Years Ago. J. M. McGregor of Detroit has furnished an exchange with the following interesting reminiscences of lake business in its early days: "Tn the village of Algonac, on the St. Clair river, there was a coaling station for steamers, kept by St. Clair & Brooks, as early as 1847. Such steamers as the Ben Franklin, Missouri, Louisiana, Nile, Niagara, Illinois, Garden City, C. P. Griffith and Empire coaled there at one time or another. These were all side-wheel steamers. _ "The growth of the grain trade from the west called into being a fleet of sailing yessels. The bark E. B. Morgan was full square-rigged on both her fore and mainmasts and carried a crew of twelve men, beside a master, two mates, a cook anda royal boy. She could not get over the St. Clair flats with a cargo of 13,000 bushels of wheat without lightering nearly 2,000 bushels. The bark Utica was of the Same rig, with the same complement of officers and crew. Her full cargo was about 12,000 bushels of wheat. The brig Oleander was also Square-rigged on both masts. There were the brigantines Philadelphia, Montezuma and Rio Gr ande, the topgallant schooners Saltillo, Rialto, ete., with erews varying from eight to ten men forward, and carrying from 8,000 to 11,000 bushels of wheat. "With a cargo carried each way these vessels made from seven to eight trips in a season. The north channel of the St. Clair river was then the only navigable one for deep draft boats, and the depth of Water was 100 feet. An ox team was used to tow the grain vessels out of the St. Clair rapids. My first recollection of a tug boat was the side- wheeled Romeo. A little later came the United, the Telegraph and the Chatauqua, side-wheelers. We had no screw tugs in those days. There was no night navigation over the St. Clair river flats. Vessels sailed down as far as Algonac and came to anchor and awaited day- light. Vessels also sailed up the Detroit river and through Lake St. Clair to Point Huron, and there awaited daylight. There was a light- house on Point Huron called Belvedere light, which was also the name of a French settlement on Point Huron, at the mouth of the Clinton river. This lighthouse was abandoned as soon as the first improve- ments made in the south channel were completed in 1857. There was no regular system of towing vessels through the rivers then, conse- quently they often occupied a week in sailing from Lake Erie to Lake Huron and 'vice versa.' There were very few lighthouses then, and vessels did not navigate the south channel of the Straits of Mackinac, but passed to the northward of Bois Blane island and between Round and Mackinac islands. The lighthouse on the north side of Bois Blane island and the lightship at Waugoshance were the only lights between Presque Isle harbor and South Manitou island. Mackinac island was one known anchorage considered safe in 'all winds and St. Helena island was another, but there were no lighthouses upon either of them." In General. Andrew Cameron, diver, at work on Loch Treig, Scotland, dived to a depth of 200 feet recently. This, it is said, is the greatest depth ever reached by submarine diving. Up till this the record diye was that at Brussels, where a diver named Valmont reached the depth of 160 feet. In a communication to the Hneancen a lake correspondent says that only 22 and 24 of the North West's 28 Belleville boilers are necessary to furnish sufficient steam to make schedule time of 19 miles per hour, The correspondent estimates that these steamers are burn- ing 700 tons of coal per round trip, which he claims is 100 tons less than last year. This is very doubtful as the amount of fuel used last year was said to be satisfactory, as was the quality of it. Experiments show that a light of one candle power is plainly visible at one mile, and one of three candle power at two miles. A 10 candle power light was seen with a binocular at four miles, one of 29 at five miles, though faintly, and one of 33 candles at the same distance without difficulty. On an exceptionally clear night a white light. of 8.2 candle power can be distinguished at three miles, one of 5.6 at four, and one of 1.2 at five miles. The management of the Fall River Line is ever on the alert to add features that will secure comfort or convenience to their passen- gers, Their latest innovation is to haye a corps of messenger boys meet their boats on arrival at New York. They will escort strangers, ladies and children to any desired place, carry parcels, etc. Their system of free cots for the poorer class of passengers is very commend- able. Stateroom rates are so reasonable that a whole room is secured for $1.50 and upwards, according to location. - If lake engineers had to furnish their own bed, bedding, linen, soap and matches it would be a just cause for a prolonged and righte- ous howl of indignation. But according to the following, engineers of English tramp steamers accept it as a matter of course: "In the large lines sailing from such ports as London, Liverpool, and South- ampton, bedding, bed and other linen, soap, and matches are provided by the companies, but in most of the tramps or 'Geordies,' hailing from the Northeast Coast, such matters are left to the engineer to provide. As regards bedding, the humble straw bed, or 'donkey breakfast' as it is facetiously called, used by the firemen and sailors is as healthy a mattress as can be used, although rather hard and prickly to any one accustomed to sleep on something less coarse.' Following is a description of the Ramapo, the new Union line steamer, launched from the Union Dry Dock Company's yard: Her main hold is diyided by bulkheads into nine compartments. Her water bottom is fifty-four inches deep, and the extreme length over all 340 feet, molded length, 336 feet; length on keel, 319 feet; depth, 27 feet three inches; beam, 44 feet. It is expected that this boat will carry 4,000 tons on sixteen feet of water, and at this draft she has-a dicnlicemnent of 5,480 tons, it is expected she will have no difficulty in running creed miles an hour. The work of construction was begun last September, and has given employment almost constantly to 500 men. iz ue