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OPE eS By ee April, 1914 hatch as we went forward to within about the sixth hatch, and then go- - ing back to about amidships and com- ing forward with another run in order to get the ship's bow down, this plan of loading had no bad effect what- ever on one of our modern ships, and after this run had been continued through, on taking the draught' for- ward, aft and amidships, the boat was practically on a straight line; that 'is, she drew as much water at both ends as she did amidships and showed no signs of material sag in the center. It has been proven out in the load- ing that if the boat is sagged in the middle to any material extent while loading, it does not improve matters any to put extra heavy loads in both ends; that is, the sag in amidships still remains until the boat is unload- ed. "But in a paper read by Naval Con- structor, Stuart: Parrar- Smith, > atthe recent meeting of the Society of Na- val Architects and Marine Engineers, held in New York City, Dec. 11 and 12, 1913;:-Mr. Smith 'stated: . That in practical experience 'the middle of _ the length of a long vessel may move up or down as much as 6 in. with ref- erence to the ends, depending on the conditions of loading without any ma- ferial "injury. .to- the ship). and. 'that a temperature rise of 1 degree Fahr. may cause a raise in the middle of the ship of as much as % in., Another paper was read by James E. Howard, engineer-physicist, covering a num- ber of experiments of strains on ships' hulls, both at sea and while receiving cargo, . Mr. Howard, in these. ex- periments used an instrument that would measure the stretching of both the deck and the side plates down to a point: of 0.0001 in.--and.by Ahese tests he was enabled to establish ac- curately the vibrations caused by the revolutions of the engines separately from the vibrations caused by the weakness of the hull or by the Sea. "Tt is a well established fact that when the vibrations of the engine are synchronous with the vibrations of the hull, caused by the sea, the vibra- tions are greatly exaggerated and conditions may be materially | im- proved by either changing the speed of the revolutions of the engine, or by changing the propeller wheel. Also in Mr. Howard's experiments, he kept record of the changes in the form of the hull at different times in the day, according to the temperature, and found that the apparent draught of the ship, taking the marks forward 'and aft, was changed as much as 2 in., and in the discussion on these papers, it was brought out that the builders or contractors of government ships THE MARINE REVIEW frequently find in certain classes of vessels that they can increase the apparent dead weight of the ship by even blowing off one of the boilers, and this is done sometimes in order to increase their bonus on their con- tracts. "We have had the question up be- fore now of boats being loaded to Proper Loading We found that beginning at the after end of the cargo hold, putting a pocket in every other hatch as we went forward to within about the sixth hatch and then going back to - about amidships and coming for- ward with another run in order to get the ship's bow down, this plan of loading had.no bad effect what- ever on one of our modern ships, and after this run had been con- tinued through, on taking the draught, forward, aft and dmid- ships, the boat was practically on a straight line. certain marks at the head of Lake Superior, and when they arrived at the Soo they were drawing more water forward than they were when they left their loading port without having come up a_ corresponding amount. ait. . This has generally: oc: curred when they arrived at the Soo during. very warm weather, and in talking this matter over with a num- ber of scientific men, who have made practical experiments in such mat- ters, they expressed themselves very freely to the effect that this difference was caused by the sun heating the decks and the upper part of the hull of the ship, and that a partial remedy for this would be to turn the hose on the decks and cool them down. It was stated that if we would take a Improper Loading It has been proven out in the loading that if the boat is sagged in the middle to any material ex- tent while loading it does not im- prove matters any to put extra loads in both ends, that ts, the sag in amidships still remains until the boat is unloaded. transit and make observations along the sides of the hull of one of our long steamers, we would find the change in the shape of the ship would be very .considerable in the effect of different ways of loading and in the different temperatures in which these 149 observations were taken. I have in mind at the present time a case which happened in Cleveland a number of years ago when the tall. electric light- ing masts ,were being built. The foreman in charge of the erection of these masts was somewhat. startled on a hot morning when he noticed that the mast was quite crooked, but as the day. went by he noticed the shape was changing and in the after- noon the bend was on the opposite side. I mention this to show how much one of our ships would be af- fected by the heat of the sun on the decks while the bottom of the hull is submerged in cold water. -- "In the tests we made on the last three boats, which were put in com- mission during the season of 1913, we noticed there was a. very marked dif- ference in the speed of the ships when good wheelsmen were at the wheel and when poor steering was being done. In one particular case, when Captain Watt was watching the steer- ing in the pilot house and I was watching the wake aft and keeping track of the revolutions of the engine, steam pressure, etc., I noticed in one hour that the speed of the boat had dropped down nearly %4 mile and also that the revolutions of the engine had been slowed up, but the steam pres- sure had been exactly the same, in fact, it had not varied as much as one pound during this period. I went for- ward to inquire how things were go- ing there and Captain Watt. informed me that the wheelsman had lost con- trol of her and did some very poor steering for a period of 35 minutes out of the hour. Another man was then put at the wheel and he did very good steering, so that the bad steer- ing, lasting only 35 minutes, had slowed the boat's speed down nearly ¥% mile during that hour. "In connection with. this, I wish to mention the statement made by one of the naval officers at the meet- ing of the Society of Naval Architects and Marine Engineers, in which he spoke of a government ship with bilge keels for the purpose of experi- menting as to how much bilge ,keels retarded the speed of the ship. The bilge keels were removed after hav- ing made a trial run.: Then another run was made over the same course with the same trim of vessel and un- der almost exactly the same. condi- tions, and it was found that it took more engine power to drive the ship at the same speed without the bilge keels than she had made with the bilge keels, but they discovered the cause, which was poor steering being done. The difference in the power was quite considerable, although I cannot