The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

July, 1909 she sailed on her first cruise under the command of Commander Wm. P. Inman. During the Civil -War. the battery was increased and in 1864 was given as one 30-pounder, five 20-pound- ers, two light 12-pounders and six 24- pounders. The name was changed to Wolve- rine in order that a first-class battle- ship, authorized: by Congress March 3, 1905; might.bear the name of that great state, Michigan. The ship has * been. ployed for recruiting, surveying and, notably during the Civil War, to guard the lake borders from attempted raids and -the tratisportation of arms from Canada by Confederate agents, and as a guard for Johnson's Island, where a great- number of Confederate prisoners was held. Her original complement was one commander, two lieutenants, one mas- ter, one purser, one - passed assistant surgeon, five passed. midshipmen, one chief engineer, four assistant engineers, one gunner, one carpenter, -twenty- variously em- three petty officers and rated men, ten seamen, ten ordinary seamen, twelve landsmen and boys, eight fire- men, four coal passers and fifteen marines. Discussion on Commander White's Paper. Henry Penton.--I -would like tos. ask Commander White if the , discov- ered why her material was anes from wood:-to iron. Commander White--I tried to find out but could not. suaded congress to change the ma- terial in the interest of the new iron industry. ; Henry Penton.--Were the boilers that were taken out in 1892 the orig- inal boilers? If so that would give them aa life of about 50 years. Commander White.--I believe te were. John Craig.--I- would like to miaked a few general remarks, not on this paper, but about the lakes. 'The art of ship owning, ship building and ship sailing on the lakes was an art until lately. The business of building, own- ing and sailing were curiously blend- ed and the whole trade was marked by enormously fluctuating values. A; ship might earn 100 per cent in a year, and yet again it might earn nothing and was worth nothing. But the business has now passed from an era of speculation to a sound and legitimate basis. Large companies now own many vessels and have brought stability into the business. The Pittsburg Steamship Co., con- Possibly a dele- gation went from Pittsburg and per- "THE Marine REVIEW trolling 112 vessels, has a broad -and brilliant man at its head. Mr. Coulby, realizing. the difficulties of lake navi- gation, annually holds a congress of his captains and their interchange of experiences 1s Of "sYent vale =i Mr. Coulby is requested I am sure that he would give a report of these meetings to this society. It would make an interesting contribution to the November meeting. "Towing Problems." Mr. T. S.. Kemble then 'presented his paper on "Towing Problems,' as follows: . The subject of this paper has been announced as "Towing Problems" to leave some latitude for the introduc- tion of any facts and theoretical con- - siderations that might be available and pertinent to the more particular problem to which in the' main it is devoted, namely, that of determin- ing the requirements arising from given towing conditions, and the man- ner. in which a towing machine and cable of given size will meet these requirements. It has been found convenient to as- sume certain concrete figures illus- trating the general method of calcula- tion which may be applied to other conditions occurring in practice. The normal or average pull on the tow line is due solely to the engines of the steamer, and is equal to the effective: thrust bi the steamer's screw, less the thrust taken up in driving the steamer itself. Waves, swerving currents, changes in steering direction and other causes may greatly alter this pull for periods of comparatively 'short duration. The character of some of the forces "acting onthe vessels and tow line may .be deduced from the following considerations: Assume a steamer of 15,000 net tons displacement when loaded, developing 1300. I. Ho P. traveling 9 miles per hour and towing a barge of equal size and weight. Assume also a pro- pulsive efficiency of 50 per cent, and neglect the loss due to the drag of the tow line through the water. (Note a). The effective thrust of the steam- er screw would then be 100 6 ea ee 2 a 9 X 5,280 say 19. tons, of which half will be used in propelling the steamer itself, and the other half (914 tons) is car- ried through the tow line to pull the barge. This is the average continu- ous-pull for the conditions stated and can be readily computed for any other given conditions. 203 The dip or sag in the line should not be great enough to allow it to drag on the bottom. In some parts of the channels' from the upper lakes to Lake Erie ports, a. dip of over 20 ft. should not be permitted. This allows perhaps 30 to 35 it., say 35 ft. below supports, Assume a 2-in. diameter steel tow- ing hawser of 125 tons breaking strength, about 80 tons elastic limit, weighing 625 dbs. per ft. in air, ang about four-fifths of this, or 5 lbs. per ft. in water. The length of this line to give 35 ft. dip with the 'lower 20 ft. of dip -- in water and with a horizontal pull of 9% tons, is 1,027 it; and the span is 3.22 ft. less (Note b and note c). If the steamer is slowed down as when making harbor, or meeting oth- er vessels, the line should be corre- spondingly shortened as the dip would otherwise be greater at the lower speed, : Now suppose the ends of the tow line to be fastened to tow posts, and a continuous net additional. force of .30 tons to come between the vessels driving them apart (Note d): The vessels would then be :accelerated apart until the resistance in ee tow line rose to 9%, + 39% tons. At this point the dip in the line is about 10.5 ft., and the length minus span is 0.3 ft. The vessels have moved apart due to the take-up of the dip 3.22 0.8 == 202 The stretch of the line due to the additional load may be taken as 2.23 ft. (Note e and Note c),.making the total increase of span 292 4.2.23 == S15 tt. The average accelerating force dur- ing this time was 30/2 or 15 tons. To stop this motion apart will require an average force, additional to 39% tons, in inverse proportion to the dis- tance through which it acts. The distance in this particular case will be found to be about 3.5 ft. Assum- ing then, to begin with, that the dis- tance through which the force acts is 3.5 ft, the average retarding force will be S15 x 15 = 22 tons. 3.5 The maximum additional force is 22 X 2 = 44 tons. making a total maximum honorees: pull of 39% + 44 = 83% tons, at the point where the vessels: cease to move apart. The dip is about 5 ft., and the vessels have moved apart 0.225 ft. due to the take-up of the-dip, and 3.275 ft. due to the stretch of: fhe line, making in all