1866.] 



Compasses in Iron Ships, 



39 



1 . The improper construction and position of the steering binnacle 

 and compass. 



2. The too frequent habit of placing all reliance upon the steering 

 binnacle compass. 



3. Allowing the compasses to be too long in use without due exa- 

 mination. 



4. The improper manner in which the compasses have been adjusted. 



1 . The construction of the compass is at all times a matter of great im- 

 portance, but when applied to the case of an iron ship its value is increased 

 tenfold; it is most essential that the compass should be of the best attainable 

 description, and so constructed that its centre and pivot should be subject 

 to the smallest possible amount of friction, in order that the needles may be 

 entirely free to follow the directive force of the earth, and have at the same 

 time great retentive power. Some years since the author observed, when 

 adjusting an iron steamer's compass furnished by him with very powerful 

 needles, discarded from some previous experiments in magnetism, and 

 which were only 4 inches in length, that more than usually satisfactory 

 results were obtained ; the deviations were of a smaller value, and far more 

 uniform than when using needles of greater length. He has since adopted 

 the practice of employing needles not exceeding 6 inches in length, even 

 for cards of the largest diameter. 



The position of the compass is also important ; it is an objectionable 

 practice of too frequent occurrence, even with the ordinary plane spindle 

 and barrel, to place the binnacle near the steering-wheel ; with the screw 

 apparatus, arms, and levers the practice becomes extremely dangerous, the 

 whole mass, from the process of manufacture, being found highly magnetic. 

 The idea, however, prevails that all this is a matter of indifference, since the 

 counteracting magnets are supposed to neutralize all magnetic disturbance. 

 The reverse, however, is the case ; many instances have come under the 

 author's notice practically in which errors have arisen solely from this 

 cause, but which ceased to exist on the removal of the binnacle to a distance 

 of 4 feet from the spindle, or twice the original distance. 



It would be far better, in all cases, if the steering-wheel could be placed 

 before the mizen-mast of ships, instead of abaft and close to the stern, as is 

 generally the case ; compasses would invariably act better and be subject 

 to smaller changes. 



2. It is too frequently the practice to place exclusive reliance upon the 

 st eerin ff-comipass j this may be attended with less trouble to the navigator, 

 but is, as regards the safety of the ship, very perilous. As ships are now 

 fitted, the steering- compass is placed very near the stern ; and since in iron 

 ships the magnetic forces are generally concentrated at the two ends of the 

 vessel, it must be obvious that it is placed at that spot where the greatest 

 variations may be expected. Every iron ship should be furnished with a 

 properly constructed standard binnacle not less than 5 feet high above the 

 deck, suitably placed, and containing a compass fitted in the most con- 



