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394 Then a mechanical stoker was installed ewhich ran the efficiency up to 78 per cent. It is pointed out that this is a . good record for either a land or marine installation. Oil fuel will be tested later and it is predicted that the efficiency will be thereby increased. THE , HOW A STERN WHEEL RIVER TOWBOAT BEHAVED DURING LAUNCHING--THE FULL LINES. INDICATE ' "THE POSITION AFTER LAUNCHING WHILE THE DOTTED LINES SHOW THE EXTREME POSITION WHILE THE CRAFT WAS TAKING THE WATER The boiler is rated at 250-horse- power. Its coal consumption, nor- mally, is about 1400 pounds per hour but by using forced draft as high -as 3000 pounds per hour have been consumed. The coal used is said to be the best grade obtainable in this country and comes from Maryland. Evaporation tests of the steam gen- erated showed that as high as 12 tons of water an hour have been used. This is approximately eight tons of water to one ton of coal. ' Improved Hatch Cover ' Hatch covers designed for use on cdrgo vessels, whether intended for inland lake or deep water service, should be watertight and proportioned to resist the impact of heavy seas during rough weather. Ease of manipulation in opening or closing the hatch is an- other factor that appeals to the vessel man. With the object of supplying a hatch cover that will meet these re- quirements, Harry S. Moore, Algonac, Mich., recently developed and patented the device shown in the accompanying illustration. The upper illustration is a perspec- tive view of the hatch cover as it is installed on the hatch coaming. In this illustration the channel bar in the fore- ground is removed to illustrate the mechanism. The lower view is a longitudinal section. The upper view shows the hatch closed while the lower illustration shows it open. In the illus- trations A is the ship's deck, B the hatchway, and C, D, E the coaming. - Two sets of cover plates are shown at H and J. These are steel plate and are constructed to overlap .each other when the hatch is closed. When the hatch is open, they arrange themselves in piles at either side. With the object of providing sufficient strength in con- struction, the plates are provided with stiffeners, K, at one side. The upper part of the stiffeners, L, forms a 'coup- ling flange which permits one plate to actuate the following member when the hatch is closed. This flange engages the following plate by means of the bent portion, M. The outermost plate of each side unit, J, is equipped with a flange, | N, which hooks over the side of the coaming at F. With the object of form- ing a watertight joint at this juncture, packing, O, is placed at the inside of the flange, N. This packing is rubber. When the hatch covers are in place, they are locked by means of the cover plate, P. The upper side portion of the coaming. is provided with a bead, G, over which a channel-shaped section, R, is fitted. The object of this member is to provide a watertight joint. For hold- ing the hatch securely in place after it is closed, clamps, QO, are provided. One end of these is equipped with a hook while the other end is provided with a set screw. ne When the hatch is: open, the plates are stowed at each side on the supports, S. The cover is operated by a tackle, T, provided at one end with a loop, U, which is passed over the pins, V. The REVIEW a material saving. August, 1919 tackle runs over the pulley, W, which is mounted on a standard, X. It is pointed out that the hatch cover does not require covering with a tar. paulin after it is closed, thus effecting It isi claimed that the cover is easily manipulated and that it makes the hatch watertight. Launches Boat Complete River shipyards are ri€arly always confronted with peculiar launching problems, tlie details of which must be worked out with mathematical preci- sion to insure satisfactory results. Many of the factors involved are shown in the sidewise launching of the stern-wheel river towboat Warren ELsry, ' recently built"at Neville Island, Pa., by the en- gineering works department of the Dravo Contracting Co., Pittsburgh. _ The launching was unique in Ohio river side launching in that the boat was practically complete. All equipment in- cluding engines, boilers, piping, stern wheel, auxiliaries and upper cabin were installed while the boat was on the ways. The hull, boiler deck and pilot house are steel, while the crew quarters on the upper deck are wood. On account of the height and weight of superstructure and machinery above the deck, careful observations were made to determine the behavior of the boat during launching. These included the maximum list, list on recovery, maximum depth of water taken, angularly of longi- tudinal axis of boat to ways when tak- ing the water, speed of boat when leav- ing ways and hogging or sagging of boat after flotation. The accompanying cross-section illustrates in part the be- havior of the boat during launching. Four pairs of launching sleds were used. These were equally spaced. They were placed under the boat athwartships and level longitudinally. The launch anes = LLL rit L N) A [pm tC Mag. 2 W #H '3 eV. y D >. > ft S71 4 K é A YW } & Zz i iat il Cm D' oO 7 B piece TIE 7 24 SHEET-METAL HATCH COVER MADE IN SECTIONS TO PERMIT EASY MANIPULATION