[17] U. S. FISH COMMISSION STEAMER ALBATROSS. 19 



SPARE TILLER. 



Fig. I shows the spare tiller g keyed to the rudder-stock /. The 

 eyebolts h for the relieving tackles slide along the whole length of the 

 tiller, for convenience in hooking in case of accident to the steering-gear. 



RUDDER-CHAINS. 



The rudder chains are shackled to the short tiller projecting from the 

 rudder, seized to an eyebolt in the stern, and carried along the quarters 

 in the usual manner. 



THE ALBATROSS DREDGING. 



Plate I represents the Albatross in the operation of dredging at sea. 

 The vessel is backing with her stern to the wind, as indicated by the 

 forward treud of the dredge-rope, flags, &c. In prosecuting this work 

 it is necessary to maneuver in such a manner that the drift will be 

 from the dredge-rope, thus preventing it from drawing under the ves- 

 sel's bottom. If steel wire rope is used for this purpose it will also be 

 necessary to keep it under tension, for if allowed to slacken, even for a 

 moment, it will kink, thus reducing its tensile strength about 50 per 

 ceut. Before putting the trawl or dredge over, then, we must decide 

 in what direction it can be dragged to the best advantage. Working 

 in a uniform depth of water this would naturally be toward the position 

 in which the next haul was to be made; but when operating on a steep 

 slope, such as will be encountered off our coast, an uphill drag is the 

 only one offering a fair probability of success. If the wind is blowing 

 in the direction of the down slope, we would turn the vessel's stern to 

 it and back the engine, but if the breeze should be from the opposite 

 direction this could not be done. We would then go ahead, keeping 

 the wind more or less on the starboard side, from which the dredge is 

 lowered. The range of direction is, of course, much greater under the 

 latter conditions, as the vessel is under control of the helm. 



Ocean currents serve to complicate in no small degree the work of 

 deep-sea exploration. A surface set is quickly detected and guarded 

 against or utilized in prosecuting the work ; but when the rope is sud- 

 denly swept under the bottom by a submarine current, with perhaps 

 thousands of fathoms of line out, it requires a great deal of tact and 

 patience to clear it from the ship and land the trawl on the bottom 

 without capsizing it or kinking the rope. 



The Albatross is represented at work under the most favorable con- 

 ditions, the trawl lowered from the starboard side, and the starboard 

 engine backing slowly. This has the tendency to keep the wind a 

 little on the starboard quarter, thus drifting the vessel away from the 

 rope, which is seen to trend somewhat off the bow. 



The greatest advantage to be derived from backing while dredging, 

 is that in case the apparatus fouls ou the bottom a stern-board can be 

 checked and the strain on the dredge-rope relieved more quickly than 

 when steaming ahead. 



