2 5 



If from previous soundings in the neighbourhood the action of the current was known, 

 soundings were frequently commenced while the ship was moving ahead or astern. If no such 

 information had been obtained the ship, after having been brought to rest in the surface water, 

 was placed in the proper direction. 



As soon as the line showed any deviation from the vertical the ship was manoeuvred 

 according to circumstances. 



One point which could be depended upon and which probably applies to all screw- 

 steamers of the ordinary type was, that with the ship lying at rest in the wind, the bow drifted 

 off and when steaming astern the stern veered ronnd in the wind. 



When only wind and waves influenced the vessel and there was none or very 

 little current, it appeared as a matter of course to place the ship, at the commencement 

 of the sounding, almost rigth before the wind, the wind striking the ship a few points on the 

 sounding side. 



Working one screw astern from time to time was then generall)' sufficiënt to keep the 

 rope nearly vertical. 



If there was but a slight current and especially when this was in the same direction as 

 the wind, or if there was but little wind, it was found best to steer against the current and 

 keep the rope vertical by steaming slowly ahead. It was hereby easier to keep a true course 

 and to prevent the line passing underneath the ship. 



When sounding in the Moluccan Archipelago in the east monsoon with a strong wind 

 and current in nearly the same direction, a speed of i 1 /,, to 2 knots had often to be maintained 

 in order to keep the line vertical. Under such conditions the ship could not be steered suffi- 

 ciently accurately with the engines working astern to prevent current and wind to come in from 

 time to time on the wrong bord, causing the line to get badly under the ship. 



Working the screws in opposite directions is only effective in very calm weather. With 

 the slightest breeze and any sea running, the ship veeres off and remains in a fixed position, 

 which most probably was not the one wished for. 



Even with the engines working at full speed the desired direction could often not be 

 obtained. Much labor and steam are then uselessly wasted. 



When much line is paid out, manoeuvring the ship on the same spot is of not much 

 use as the horizontal movement of the wire is too slight in comparison to the length paid out. 

 For with a strongly slanting long line, the horizontal distance between the ship and the 

 lead is great and the principal question is evidently to reduce this distance as much as possible, 

 or in other words, to keep the ship vertically over the sounding lead or to bring it back to 

 that position. 



Perhaps this object may sometimes be obtained by alternately steaming ahead or astern 

 combined with the necessary changes in the ship's course, but this is an unpractical method, 

 involving constant manoeuvring and a large consumption of steam, with the line sometimes 

 trailing forward ,and sometimes astern. Not only is there a chance of the wire having a very 

 slanting position at the moment the leacl touches ground, but the tension in the wire is so 

 irreeular that the soundinof machine works verv irregaüar. 



S1EOGA-EXPEDITIE II. 4 



