2 EKMAN. ON DEAD-WATER. |norw. pol. exp. 



or a couple of stripes stretch obliquely aft from the sides of the ship. They 

 are described as "rips" or whirling "current backs" 1 ; also as stripes of hop- 

 ping wavelets. These stripes often stretch far away from the ship. They may 

 be seen in the various sketches Figs. 6—13 of PL IV, which are copied from 

 original drawings, appended to some of the mariners' accounts. An indication 

 of similar stripes may be seen in Fig 5. Fig. 1, PL V — illustrating the 

 same case as the schematic sketch Fig. 10, PL IV — gives a more objective 

 representation of the phenomenon. Prof. Nansen himself does not speak of 

 any such rips or stripes but he observed very long and low waves, stretch- 

 ing across the wake of the Fram; the crest-lines of these waves are shown 

 on the rough sketch, Fig. 1, PL IV. 



Round the ship's stern a wake is formed of unrippled, eddying water, 

 which is said to follow the ship and even to advance towards her, so that 

 a boat in tow will be carried in close up under her stern. The stripes is- 

 suing from the sides of the vessel seem to form the boundary line between 

 the water following the vessel and the water outside. It is commonly believed 

 that a bulk of water is clinging to the vessel; and this proceeds through the 

 water outside, with a roar. It draws off from the vessel with increase of wind, 

 and vice versa. Likewise the stripes crossing the wake are said to come 

 nearer to the stern, the more the wind slackens. 



It is a peculiarity of dead-water, that it always appears quite suddenly. 

 Its influence upon the steering of a ship, or the appearance of the sea-surface 

 may, in some cases, be subject to gradual modifications; its effect upon the 

 speed of the ship always takes place, however, quite suddenly, the speed be- 

 ing at once reduced from its ordinary magnitude to a small fraction thereof. 

 It very often happens, moreover, that the ship has dead-water at the very 

 outset. Just as suddenly does the ship recover her ordinary speed when she 

 gets rid of the dead-water — "as if cut away from a mooring astern". Some- 

 times she soon gets free, but on particular occasions vessels may remain 

 helpless in the dead-water for a whole clay or even longer. 



Usually it is only vessels in tow and sailing vessels in a light breeze 

 (vessels with comparatively small motive power), that are influenced by dead- 



Smooth or agitated streaks often seen on the sea, denoting the boundary between two 

 currents with different motions. 



