With tiese values one obtains from Plate I: 



Minimum duration, t . = 43 hours. 



Since the duration is shorter than 43 hours, Plate IV is used, 

 from which one obtains: 



Ep, - 18.0 feet, Tj, = 9.0 seconds. 



The distance of decay was 600 miles. Entering Plate VI with 

 a period of 9.0 seconds and a distance of decay of 600 miles, a 

 travel time of 40 hours and a reduction factor of 0.47 are read 

 off. Consequently, the swell should arrive at the northwest coast 

 of Morocco In 40 hours, that Is, on November 9 at 05?^0, G.M.T., 

 with a height of 8.5 feet. From Inset II In Plate VI one finds a 

 factor of 1.27 for the period Increase, that is, the sv/ell should 

 arrive with a period of about 11.4 seconds. 



The calculations can be tabulated as follows, using the sym- 

 bols in Table IV: 



Numerical value 



1.6 degrees of latitude 



40° N. 



straight 



50 knots 



32.5 knots (factor O.65) 



29 knots (adopted average) 



8 Beaufort 



800 naut. m. 



32 hours 



54 



