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Low Cost of Lake Transportation Major Importance of Highly Efficient Loading and Unloading Equip- ment at Shore Plants— Port Time Is Reduced to a Minimum l(t Society of Naval Architects and Marine Engineers and trans- portation interests as a whole, which includes builders, owners, ship- pers and operators, are to _ be congratulated upon the generous con- tribution by the American Ship Build- ing Co. through A. W. Cross, its naval architect in his presentation of the paper on Recent Developments in Shipbuilding on the Great Lakes. Mr. Cross is peculiarly competent as to his subject since he has lived with it all his life and through its most intensive development. This familiarity also has its drawbacks in the prepara- tion of such a paper because the in- timacy tends to minimize the out- standing features of the subject. Since the development of the type ship cannot be disassociated from that of the shore plant—in fact the two are interwoven—I have taken the liberty of offering some data which may help those unfamiliar with the trade to a better understanding of the factors underlying and controlling such de- velopment. The papers by W. I. Babcock in Vol. 13, R. B. Sheridan in Vol. 17, Professors Sadler and Lind- blad in Vol. 30 and Professor Lindblad in Vol. 31 of the transactions, will supply considerable additional his- torical and other pertinent data and should by all means be read in con- junction. Because, in such relatively short voyages, reduction of port time is all-important, much more so than the question of speed of ship, every effort has been bent in that direction. Thus, the shore plant has been steadily improved to economize the ship’s time and the ship has been coincidentally, modified to facilitate and take ad- vantage of the utmost possibilities of the shore plant. As regards the ship, a design is aimed at which assumes the highest rate of loading or unloading to be a sustained or standard performance and it may therefore be of interest to show some of these rates and their This article was presented by the author, Henry Penton, to the Society of Naval Archi- tects and Marine Engineers as a written discus- sion on the paper by A. W. Cross on Recent Developments in Shipbuilding on the Great Lakes. It is a clear statement of the real nub of the marvelously efficient transportation system of the Great Lakes, by a man who has had many years of intimate contact with the design and construction of vessels for Great Lakes service. By Henry Penton influence on transportation and _ ship- building. Some of them are frankly tests, such as the loading of the S. S. Kerr, but indicate a _ condi- tion liable to recur at any time or even become established practice, be- cause the history of the trade is that what was phenomenal yesterday is commonplace today. A little later will appear evidence of how rapidly the test load conditions of 1921 were be- ing approximated in 1927. Ore Loading Speeds At this time, however, the _ test loading rate of 12,508 gross tons of Henry Penton Well known Great Lakes consulting marine engineer, elected a member of the council of the Society of Naval Architects & Marine En- gineers at the last annual meeting ore in sixteen and one-half (16%) min- utes into the steamer D. G. KERR in 1921 has not been disturbed. This test merely established a rate of flow for ore with a spout into every hatch on 12-foot spacing. It does not mean that the ship was cleared of water ballast and ready to depart in that time. It does, however, establish a condition. Average loading conditions may be presented in a number of forms but it is thought best to give here the ordinary procedure which involves MARINE REVIEW—December, 1928 shifting the ship under the spouts, handling water ballast, etc. The largest of the ore docks, the Duluth, Missabe & Northern rail- road, at Duluth, in 1927 loaded 1672 cargoes averaging 9200 gross_ tons each, in an average loading time of 2 hours, 55 minutes, and average time at dock, including all shifting, han- dling water ballast, ete., of 4 hours, 5 minutes. The Lake Superior & Ishpeming dock at Marquette loaded 290 cargoes averaging 8100 gross tons each in an average loading time of 69 minutes per cargo. The time shifting and pumping is not stated but would add about an hour to each. The Great Northern dock at Superior gives a random list of ships averag- ing 11,260 gross tons per cargo with an average loading time of 2 hours, 42 minutes and total time at dock of 3 hours, 24 minutes. The manager of this dock advises me as follows: “On many grades of ore it is now no longer a question of how fast the docks can give the ships the ore but rather as to how fast the ships can receive it. There are many instances of putting two runs into a vessel of between 9000 and 10,000 tons in about a half an hour.” Herein lies the evidence of rapid approximation to the test loading fig- ures referred to above. Thus the ships are faced with the necessity for fast shifting and rapid handling of water ballast if they are not to take de- tention and the next move appears to be up to the ship. It is only fair to say that as to these items (shift- ing and handling ballast) the personnel is even more of a factor than the designer. Ore Unloading The ore unloading rate has been accelerated to the present figure for a full cargo of 11,445 gross tons in 2 hours, 20 minutes with five rigs work- ing, an average of 16.38 tons per min- ute per rig. This rate, established in the summer of 1927, has not been dis- turbed at last available reports and shades off with different docks, ships and cargoes. The ship described by Mr. Cross unloaded on Sept. 1 of this year the largest ore cargo moved on 37