20 



This wheel is apl to work loose owing to the vibration of the machine to be observed 

 by the reduced tension in the wire. To prevent this taking place it is advisable not to oil the 

 adjusting screw bnt simply to keep it free ot rust. 



During the hauling in the action of disc and other parts is as follows. 



On screwing up the adjusting-wheel the friction is increased between the disc and cylinder 

 which carries the wiredrum. Now seeing that the circumference of this drum is somewhat 

 oreater than that of the winding-drum and that it increases with the amount ol wire wound 

 on it. it necessarily must slip, due to the amount of clifference in circumference with that of 

 the windine-drum and the tension of the wire between these two drums is re^ulated by the 

 amount of friction between them. 



YVhen the indicator shows that the leacl is near the surface, the speed is reduced or 

 the winch stopped and the rest done by hand, although after long practice it is possible to 

 iise the winch to the very last. In which case the steam is shut off when there is about 

 20 metres of wire out and the accumulated power in the flywheel does the rest. At the 

 proper moment the brake is applied and the flywheel stopped by hand. The lead is then hauled 

 on board. 



During the hauling in the weights on the scale are gradually reduced unless the ship 

 is rolling heavily as it is then better to leave them on and keep a sharp look-out on the 

 position of the scale. 



With single wire the indicator returns very nearly to zero but with a spun line there 

 is usually a certain amount of stretching. It is always advisable not to trust entirely to the 

 indications of the counter but to watch the line as well and sjive direct warnine should the 

 weight unexpectedly appear before its time. In this case it is of advantage that the ship be 

 steamingf ahead as the amount of wire in view is then increased. 



'ö 



The sotmding Wire. 



i> 



( )n the Siboga the wire used was 0.9 millimeter diameter manufactured by Felten & 

 Guillaume of Miihlheim on the Rhein. The breaking strength was between 150 and 180 kilo- 

 grammes, it is however advisable not to put a greater strain upon it than one half of this or 

 say a maximum of 90 kilogrammes. 



Thousand metres of this wire weigh 5.1 kilogrammes and cost ƒ16.21. 



'I he original supply was one roll of 6000 metres and one of 9000 metres but later on 

 another roll of 5000 metres was supplied. 



The sounding machine had one drum which could carry 10000 metres of this wire and 

 another drum that could take 9000 metres of twisted wire. 



To wind the wire from the wooden reels on which it is sold on to the wiredrum, 

 the reel is placed on a horizontal shaft at some distance from the machine. The end of 

 the wire is wound live turns round the winding-drum, then passed over the top guide pulley 

 on to the wire drum. The steam winch is started and the proper tension put on by the 

 adjusting-wheel. 



