94 NOTES ON THE PERFORMANCE OF THE S. S. TYLER. 



3. Under Condition 3- — ^maximum efficiency decreased by diameter reduction. 



4. Combined Conditions 2 and 3 — maximum efficiency decreased by both thrust deduc- 

 tion and diameter reduction. 



The greater number of single-screw cargo steamers suffer the losses as in 4, and these 

 losses are greatly aggravated where the midship section is fined down at the expense of the 

 after body lines, and where the designed revolutions of the propeller are low, thus aggra- 

 vating both sources of loss. 



In the case of the Tyler, the effect of the full midship section was to reduce the thrust 

 deduction to a minimum for that block coefficient, while an analysis of the propeller indi- 

 cates that the reduction in diameter of propeller was practically nil, thus escaping this latter 

 serious source of loss. 



The vessel reflects great credit on both the naval architect who is responsible for the 

 design of the hull, and the engineer who designed the propeller and machinery. 



The Chairman : — Is there any further discussion? If not, Mr. Rigg, do you desire to 

 reply ? 



Mr. Rigg: — Mr. Chairman and gentlemen, in regard to Professor Peabody's question, 

 as to how we got the ship loaded, I think the explanation is twofold. The first part of 

 the answer is the first two lines of the second paragraph of the abstract, which reads as fol- 

 lows: "In view of the endeavors being made to-day to improve the propulsion of vessels, 

 it is refreshing to meet and do business with owners who are sufficiently keen to have 

 models towed and proper trials run." That is one part of the difficulty settled — the willing- 

 ness of the owners to do it. 



The other part of the answer, perhaps, needs a little explanation. It is not always easy 

 to get ships to a suitable measured mile course without interfering too much with their 

 regular run. This vessel runs from New York to Norfolk, the ship was loaded at New York 

 and then run down to the Delaware Capes on the regular run south, and she there spent 

 a few hours standardizing. Not all ships are on a route so handy to a suitable trial course. 

 She was detained at the Delaware Capes for only a few hours, and afterwards proceeded to 

 Norfolk, Va. 



I am glad to hear Captain Dyson's comments on the paper, and am sorry he is not here 

 with us. In reference to his remarks as to the full midship section and fine ends, I need 

 do no more than refer you to the naval constructor's paper read here this morning, and 

 although the paper has not been at my disposal very long, I have made a hurried reference 

 to the curves which are contained in that paper, and find that the Tyler runs within two per 

 cent of Naval Constructor Taylor's most efficient midship section. Captain Dyson, as most 

 of us know, has done a great deal of valuable work on screw propellers lately, and we all 

 should be grateful for the very liberal way in which he places the results, of his work at our 

 disposal. 



The Chairman : — 'Gentlemen, this practically completes the work for to-day. The meet- 

 ing will stand adjourned until ten o'clock on Friday morning. 



