Mr. Niedermair. Also, for vessels which spend a considerable portion of their lives at 

 anchor, the resultant fouling of the surfaces by marine organisms can increase the 

 resistance to a very great extent. Our aeronautical friends have achieved considerable 

 success in aircraft by the use of laminar flow wings and the question is often asked 

 whether advantage can be taken of this idea in ships. The degree of smoothness 

 required to maintain laminar flow is exceedingly high and it is doubtful if it could 

 ever be achieved on a ship's hull. Even if it were, excessive care would have to be taken 

 to prevent fouling, as this would rapidly eliminate any chances of maintaining such 

 a flow. Moreover, in the case of surface ships it is probable that the sea near the 

 surface is so turbulent that the achievement of laminar flow is physically impossible 

 anyway. Perhaps the best hope for such success would be in submarines or torpedoes 

 running very deep, where the level of turbulence in the ocean might be very low. 

 There have been many other suggstions for reducing frictional resistance, including 

 the use of soft surfaces similar to those of fish, of various liquids which would be 

 slowly shed and of blankets of air bubbles. It has yet to be demonstrated that any of 

 these can produce lower drags than a hard, clean, smooth paint. 



The other important component of resistance in a surface ship is the wave- 

 making. The amount of this is very small at low speeds, but increases very rapidly 

 at higher speeds and makes the achievement of these speeds very costly. There are two 

 possible ways to overcome this barrier: to go below the surface or to lift the main 

 body of the ship clear of the water by means of hydrofoils. The submerged cargo ship 

 has been considered many times, and there are certain cases where such a craft would 

 be invaluable for military use. A commercial, completely-submersible ship would have 

 many handicaps to overcome in comparison with a surface craft. The hull would be 

 much heavier and more complicated, and for the same available deadweight would 

 have to be considerably larger than the corresponding surface ship. Because of this 

 and the fact that the ship would be completely submerged, the wetted surface would 

 be much greater and therefore at low speeds the resistance would be considerably 

 higher. The advantage of complete submersion on the wavemaking resistance would 

 therefore not appear until relatively high speeds were reached; then the saving in wave- 

 making would be such as to offset the initial increase in skin friction. There would 

 also be considerable difficulties in the handling of cargo in such a craft, and the most 

 promising developments in this respect would be for oil-carrying vessels. 



Lifting the body of the craft out of the water with hydrofoils also introduces 

 many problems in anything but small size ships. In larger vessels capable of carrying 

 any appreciable deadweight, the problem of the size and weight of the foils and their 

 supports becomes a serious one, as does the excessive draft in port when not foil-borne. 

 As such craft, to be of any value, would have to be high speed vessels, the problem 

 of power and its transmission to propellers located deep below the craft also becomes 

 extremely difficult. 



In the realm of ship motions, great efforts have been devoted in the past to 

 the reduction of rolling. This is very desirable for military vessels today in view of 

 the many delicate instruments and weapons which they carry. As regards comfort 

 in passenger vessels, it has always been my personal experience that pitching is far 

 more uncomfortable than rolling. Some years ago the Model Basin collaborated with 

 the Naval Medical Services in an effort to determine the cause of seasickness. We 

 supplied instruments and observers to record the pitch, roll, heave and accelerations 

 on certain Navy transports running between New York and Europe. The Medical 

 Corps provided doctors who administered different anti-seasickness drugs to the troops 

 in the various compartments on the ship. There were many confusing features in the 

 results, but one fact certainly did seem to be quite clear. As the weather deteriorated, 

 the first cases of sickness appeared at the ends of the ship; as the weather got worse, 

 the degree of sickness in the end compartments increased and the incidence spread 

 inwards towards midships. An analysis of the results appeared to give very good cor- 

 relation between the incidence of seasickness and the vertical acceleration. Any attempt 



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