In figure 28 the results of observations made in December 1936 

 and January 1937 from lightship AUSSHWEIDHl (western North Saa) in a 13- 

 meter water depth are plotted o Data from this lightship are of particular 

 significance since they were observed in a relatively shallow region » 

 Here the seas due to wind from land and from the open sea are indicated 

 separately. I^e most turbulent states of the sea were caused by winds 

 from the open sea, but land winds also caused considerable turbulence. 

 Maximum estimated values due to land wind were a state of the sea, 6, and 

 a wave height of 3 meters. The observed wave dimensions here were not 

 checked by measurements. According to the reports of the observers the 

 wave steepness was between 1:9 and ljll4„ For a state of the sea, 3 

 and less (Douglas Sea Scale), h/L is always less than 1:20, During the 

 period in which the observations were made, a particularly great number 

 of high seas were encountered. Numerical values may shift considerably 

 if other periods of observation are chosen. 



Figure 29 represents the corresponding results of observations 

 made from the lightship FEH«mRNB]2.T in the mitic Sea in a 27-meter 

 depth. In this case the wave steepness values are less scattered. All 

 values lie in the sector betv/een 1:10 and l:35o The flattest waves 

 (1:35) occurred viith very small wave heights (H = 0,30 m) and the steep- 

 est ?raves occurred with the greatest wave height 3,10 meters in which 

 case the state of the sea vras given at 7, On several occasions the 

 state of the sea was estimated at 8, where the wave heights were smaller 

 (about 2,5 meters), but the wave lengths had their rhaximum value 

 (50-60 m)o 



In figure 30 values of wave dimensions measured at lightship 

 FEHMARNBELT are plotted in the same manner as above. The values here 

 are not the greatest in each case, but the characteristic values mention- 

 ed in section II b„ The data used was taken over various periods of 

 time during the months of September, October and November 1936, They 

 include very tranquil states of the sea up to wave heights of 0,1 meter. 

 At these tranquil states of the sea even the shallowest waves have 

 steepness up to H/L = 1:50 while the steepest wave with H/L ==1:1-!+ 

 occurred at a state of the sea zi,. The mean wave steepness is about 

 H/L = 1:25, Figure 30 illustrates the manner in which wave dimensions 

 increase with increasing values of the Douglas Sea Scale, 



Summary 



According to observations of the captains of German lightships, 

 the highest waves in the southwest region of the North Sea are 8 to 9 

 meters high, in the eastern part 5 to 6 meters, and in the &ltic Sea 

 a good 3 meters. The estimates of the observers were checked and 

 verified as to order of magnitude by means of instrument measurements, 

 but only for relatively tranquil states of the sea. 



If a marine craft is to be operated 75 per cent of the time 

 during a stormy winter wave 1 meter high can be anticipated in the 

 Biltic Sea and waves 2 meters high in the North Sea, If a marine craft 



11 



