THE EFFECT OF PROPELLERS ON THE STEERING OF VESSELS. 423 



without having advanced five lengths in her original direction. That is 

 to say, a ship can turn a circle of not greater radius than four lengths 

 more or less (see Hankoio, Valetta, Barge) ; so that, even if running at full 

 speed directly on to a straight coast, she should be able to save herself by 

 steaming on ahead and using: her rudder after she is too near to save her- 

 self by stopping ; and any obliquity in the direction of approach, or any 

 limit to the breadth of the object ahead, is all to the advantage of turn- 

 ing, but not at all so to stopping. 



There is one consideration, however, with regard to the question of 

 stopping or turning which must, according to the present custom, often 

 have weight, although there can be but one opinion as to the viciousness 

 of the custom. This consideration is the utter inability of the officers in 

 charge to make any rapid use of the rudder so long as their engines are 

 kept on ahead. It is no uncommon thing for the largest ships to be 

 steered by as few as two men. And the mere fact of the wheel being so 

 arranged that two men have command of the rudder, renders so many 

 turns of the wheel necessary to bring the rudder over that, even where 

 ready help is at hand, it takes a long time to turn the wheel round and 

 round so as to put a large angle on the rudder. 



The result is that it is often one or two minutes after the order is 

 heard before there is any large angle on the rudder, and of course under 

 these circumstances it is absurd to talk of making use of the turning 

 qualities of a ship in case of emergency. The power available to turn 

 the rudder should be proportional to the tonnage of the vessel, and there 

 is no mechanical reason why the rudder of the largest vessel should not 

 be brought hard over in less than fifteen seconds from the time the order 

 is given. Had those in charge of steam-ships sufficient control over the 

 rudder, it is probable that much less would be heard of the reversing of 

 the engines in cases of imminent danger. 



REPORTS OF THE TRIALS OF THIS TEAR. 



s.s. North-Western, February 7, 1878. 

 Right-handed screw. Speed of ship 13 knots. Signalled to engine- 

 room " Stop." "Full speed astern" 20 seconds after first order. Engines 

 moving astern. Helm put hard a-starboard. Head commenced moving 

 to starboard and went from N. 20 E. to N. 50 E. in 1^ minute. The 

 vessel had by this time stopped going through the water. We then got 

 up full speed ahead, stopped, put the helm hard a-port, and reversed 

 full speed. The vessel had stopped going ahead in 1^ minute, and the 

 head had gone to starboard from N. 30 E. to N". 50 E. At 2£ minutes 

 the head stopped going to starboard, and at 2\ minutes the ship's head 

 was going to port. The vessel was going astern through the water 

 before her head stopped going to starboard. 



The draught of water was 9 feet 2 inches and 12 feet 10 inches. The 

 centre of propeller is 7 feet 1 inches above bottom of keel, and the pro- 

 peller is 13 feet in diameter, so that the top of the blade was 9 inches out 

 . of the water. 



W. BOTTOMLET, Jun. 



Remarks by the Committee. 



The screw of this vessel being right-handed, its tendency when 

 reversed would be to bring the vessel's head to starboard, and, owing to 



