24 



EKMAN. ON DEAD-WATER. 



[NORW. POL. EXP. 



fallen into the same mishap as we. During an hour and a half I endeavoured to get the 

 ship into her course, but to no purpose ; then, it became calm. 



"In the evening a sounding was taken, and I then found that a strong under-current 

 was running just below the keel of the ship or else that she was carried away by a sur- 

 face-current of considerable velocity. As soon as the lead was about half a meter below 

 the keel, it was forced under the ship, and the line pressed against the ship's side. Although 

 it was calm during the whole night, the brig next morning was close to the Pater Noster 

 light; thus she had been carried by the current across the Kattegat from Skagen. 



"In the morning (May 29th) a gentle SW. breeze sprang up, strong enough to enable 

 the fishing boats to sail past and around us, at a good speed; but the brig could by no 

 means be brought out of her course straight towards Pater Noster. It was only at about 

 half past five that we, all at once, felt as if the ship had broken loose, and from that 

 moment we had her in our power. We headed without difficulty close to the wind and 

 thus beat southwards at 3 knots, which speed was increased in the course of the day to 

 4 or 5 knots. 



"Several vessels were seen during the day, most of which seemed to feel the dead- 

 water. In such cases they lay with the wind athwart or on the quarter, with head-sails 

 shortened and usually the rudder made fast. A ship could be seen making good bead-way; 

 she suddenly fell two or three points to leeward, the steerman worked the rudder to and 

 fro — to no purpose — , then the head-sails were shortened, and we knew that the vessel 

 had got into dead-water. 



"Several times the Gladan got into dead-water during the day, especially in the 

 neighbourhood of other vessels that lay in dead-water, but she always soon got rid of it 

 again." 



No. 15. Mr. Michael Leegaard, engineer to the Norwegian Harbour 

 Administration, has kindly communicated to me the following facts with the 

 idea of giving an explanation of the phenomenon of dead-water. 



"At Eaersund the river-current and the 

 tidal current from Nysund sometimes en- 

 counter one another as in Fig. 1. Along 

 the line of encounter there is formed a "rip" 

 or "current-back" A B, where the water is 

 "boiling". This rip has the form of a cur- 

 ved line, and remains stationary as long as 

 the conditions are unaltered. If a boat be 

 steered for some distance on either side of 

 the rip and then be left to herself, she will 

 be carried in towards the rip and will lay 

 herself along it. Then she will be carried 

 downwards along the rip, following even 

 its smallest windings, all the while being 

 followed by a "boiling" wake aft. The boat 

 cannot be made to turn across the rip with- 

 out some considerable effort, and she im- 

 mediately turns back into her former direc- 

 tion along the rip." — — — — — — — 



Fig. 1. 



"That a sailing vessel with slight wind is inclined to take "dead-water" might be ex- 

 plained with the aid of the facts mentioned. The vessel will be carried by the current 

 into the "rip", there — by the effect of the current impelling her from both aides — she will 

 take her own course along the rip and be slowly carried down stream." 



