206 report — 1877. 



APPENDIX. 



Extract from Report of Captain of Steam Reserve at Portsmouth, data! 



24th January, 1877. 



Experiments on tlte Turning of Screw Ships. 



I have the honour to report that, as already reported in my letter, dated 

 30th "September, 1870, to the Admiral Superintendent (through whom 1 

 received the original copy of experiments required), there have been no 

 opportunities of making experiments on this subject, on account of ships 

 going out on trial having their time fully occupied, and there have been no 

 ships in the First lieserve which could be taken out for the purpose. 



Observing, however, from the report in the ' Nautical Magazine ' referred 

 to, that the largest vessel of which particulars of trial are given is only 

 80 tons, I took the ' Speedy,' of 273 tons, out and tried the experiments 

 required with her : her speed is only about 5 knots ; draught of water 7 feel 

 10 inches ; rig one small mast forward ; screw right-handed, Griffith's, two- 

 bladed, diameter 6 feet 1 inch, pitch feet. The results are given in at- 

 tached sheet. 



An opportunity also occurred of getting one trial of No. G in the ' Eu- 

 phrates,' while waiting for tide. While going ahead the screw was stopped 

 and reversed, the helm being kept amidships ; the ship's head came steadily 

 round to starboard (windward) 12 : till head to wind, then fell off to port, 

 and continued to do so till stern to wind. An experienced pilot (Mr. 

 Harding) who was with me told me beforehand that this would be the case. 



The experiments with the 'Speedy' were conducted by myself, with the as- 

 sistance of Staff-Commander Parker, and Mr. Iril By, chief gunner of ' A sia ' for 

 lieserve. 



I think it may he taken as nearly certain that in all cases of putting the 

 helm over and reversing the screw at the same time the ship will obey the 

 helm for a limited time, the amount depending on the way the ship has, her 

 rig, and the direction of the wind and sea with reference to her course, and 

 that as she loses her way she will fall off from the wind until she brings it 

 astern or nearly so. Also, that on reversing the engines with the helm kept 

 amidships, she will come up head towards the wind, and then fall off before 

 the wind as she loses her way. 



It is going beyond the part of the article marked for my remarks, but I 

 would venture to express an opinion that it would be highly undesirable to 

 remove the obligation now imposed on ships " approaching each other, so as 

 to involve risk of collision," to reverse their engines. If the action of ships 

 with engines reversed is as I have said above, the reversing not only reduces 

 the risk of serious damage, by lessening the way of both ships, but brings them 

 parallel to each other, thereby placing them in a good position to avoid collision. 



I would also submit that it is desirable that attention should be called to 

 the power of the steering-gear. I think it probable that in large steamers 

 of great speed, with small crews, aud not fitted with steam steering-gear, 

 the number of men usually kept at the wheel would be found quite inade- 

 quate to get the helm hard over till the speed of the ship was reduced. 



It is worth consideration whether it should not be made obligatory, on 

 steam-ships over a certain size and speed carrying emigrants or passengers, to 

 be fitted with steam steering-gear, which I believe is not the case at present. 



I believe a doubt exists with many people whether it is safe and proper 

 to reverse engines when going at full speed ahead at once to full speed 

 astern ; this doubt (if it exists) should be removed, and it should be clearly 

 understood that engines arc to stand being suddenly reversed from extreme 

 speed one way to the opposite extreme. 



