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58 gulf with cargoes, then four voyages between gulf ports, back to the lakes via Baltimore and 10 trips on the lakes up to Nov. 25, 1924. The sister vessel has had a similarly busy itinerary. On the Great Lakes, 6384 tons of cargo were handled within a total period of four to five days with two 20-hour runs in- cluded. Excellent results were also ob- tained while in the gulf service. In the table below, several specific amounts of cargo handled under ordinary operating conditions and the corresponding time is noted. These records were taken from the ships’ log. ‘Cargo Tons handled Time per hr. Tons per tons inhrs. ofship Crane hrs. crane hr. 1060 1265 85.0 25.0 42.3 1927 33:5 57.5 67.0 29.8 2057 24.0 85.8 48.0: 42.9 With heavy steel cargo, the maximum capacity one crane in one hour per hatch has reached 102 tons. For full loading cf a general steel products cargo, 2100 tons may be handled in 24 hours. This means that 2100 tons of cargo can be placed in the ship in a period of 24 hours which would mean 87.5 tons per hcur of the ship and 43.8 tons per crane hour. Two of the practical records quot- ed above are nearly equal to full load- MARINE REVIEW ing and the remaining record though not as high, shows good performance. For similar cargo, the usual ocean freight vessel will be considered as doing satis- factory work if from 35 to 45 tons per hour are handled. Description of Cranes From the accompanying illustrations showing the STEELVENDOR in active serv- ice, a clear idea may be obtained of the type of crane used, its installation and operation. The four cranes were espe- cially designed and built by the Brown Hoisting Machinery Co., Cleveland, for these vessels. Though of a special de- sign, the crane resembles in general what is known as the locomotive type. The rated capacity at maximum outreach is 5 tons, at a lifting speed of 130 feet per minute, and a rotating speed of 3 revolutions per minute. In actual serv- ice, it has been found that 7% tons might be lifted. The limits of operating radius from the center of rotation, is 21 feet minimum (which is just under one-half the beam of the vessel) to 50 feet maxi- mum. Luffing of the boom may be ac- complished from the minimum to the maximum radius or vice versa, at a rate of 5 feet per second or in about six Fig. 2—Detailed view of one of two 5-ton, 3-motor electrical level luffing cranes as arranged for unloading motorship SrrpivEnDoR February, 1925 seconds for the entire travel. Three separate electric motors carry out these functions as follows: One 65 horsepower motor for hoisting the load, one 25 horsepower motor for rotating the crane, and one 15 horsepower motor for lufing or varying the radius of outreach of the boom. All three operations may be carried along simultaneously, and the load can be maintained automatically at any desired level while raising or lower- ing the boom, thus causing the load to travel in a horizontal plane reducing the pcwer necessary to a minimum. One man, of course, controls all three opera- tions. Though it must be admitted that such an operator requires more skill and intelligence than an ordinary winch man, no difficulty has been experienced in ob- taining such men either in the gulf or on the lakes. When the vessels make re- peated trips to the same port, the same men have generally been used. With ordinary winches and booms stepped on derrick posts or masts, booms in fixed position are used, one for lift- ing the load and the other for moving it from over the hatch to dock or to lighter at the side of the vessel. In this way, the load can only be dropped or picked up within an extremely limited area ‘where there is no aid from dock machinery. This always presents the problem of moving the cargo away from or to this limited area in order to make room for additional loads from, or to supply such loads to, the ship’s boom. Using a crane of the type under discussion here, it is possible, for in- stance, in this particular case with an outreach of 50 feet to cover an area of approximately 1800 square feet reck- oned from the side of the vessel. The STEELVENDOR and STEELMoTOR have two large hatches, each 20 feet wide by 40 feet long, and the fixed bases for the cranes are mounted on steel decked foundations raised to the level of the hatch coaming stiffeners, a few inches below the upper edges of the hatch. One crane is located between the two hatches and the other aft of the after hatch. These decked platforms are thoroughly stiffened and supported for carrying the cranes, by additional structural work underneath. Each crane weighs 70,000 pounds. At sea, the booms are lowered down into a horizontal position over the after hatch and secured in appropriate boom rests. The standing part of the crane is stepped into position on its permanent base, the weight alone holding it in posi- tion. It was found in coastwise service, when encountering heavy weather -that their own weight is not sufficient for keeping the cranes safely in position Heavy steel guys with turnbuckle con- nections were rigged from the top of each crane to pads in the deck, two on