NO. IB.] EXPLANATION OF THE DEAD-WATER PHENOMENON. 107 



vessel than of the other — especially if she lies deeper aft than fore — and 

 would consequently endeavour to turn her in a particular direction. The ship 

 obviously ought to turn her stem in the direction of the surface-current, just 

 as Mr. Eriksen mentions (p. 18). In this way it is also possible to explain, 

 why a vessel in a particular case, could be manoeuvred as long as her course 

 was within the angle between two particular directions, while it was impossible 

 to bring her into a course beyond this angle (accounts Nos. 13 and 14); if 

 the surface-current, under-current, and wind combined, try to keep the vessel 

 in a certain direction of equilibrium, the power of the helm might be sufficient 

 to turn her only to within a certain angle to each side of this direction of 

 equilibrium. 



If the surface-current is strong enough, it may, of course, have a similar 

 effect upon the steering, even if the power of the helm be not reduced by 

 dead-water. When the steering is influenced, although the ship keeps 

 her ordinary speed — as Mr. Eriksen mentions (p. 18) is sometimes the case 

 in the Kattegat — the cause is certainly a surface-current and not dead- 

 water. It might therefore be possible, that the accident in account No. 14, 

 depended on a surface-current only — especially as no effect upon the vessel, 

 except on the steering, is mentioned. The only circumstance, in this case, 

 which is very characteristic for dead-water and which makes it probable that 

 this has been the cause of the phenomenon, is that the steering was lost 

 suddenly when the sail-area was diminished, and was not regained when 

 the sails were set again. 



The sudden effect produced by the stopping of the engine, 



It was noticed that the Fram, when in dead-water, stopped dead 

 when the engine was stopped — in one or two or even in only half a 

 ship's-length (see pp. 10, 11, 12), and she even seemed to be sucked back 

 again. Mr. G. A. Larsen has noticed the same thing when towing lighters 

 at the mouths of the Glommen River. According to him, the lighter stops 

 short, and then moves alternately backwards and forwards several times as 

 the "dead-water stripes" pass by, when the engine of the tug is stopped 

 (see p. 14). 



Although the explanation of these phenomena is, in reality, very simple, 

 I nevertheless made a few experiments in verification. The larger of the 



