The statistical presentation of wave data given here will show at a glance the probabil- 

 ity of exceeding any given sea condition (as specified in terms of a characteristic* wave 

 height) in an average year, for ten representative locations in the Atlantic Ocean. Such infor- 

 mation can be utilized in the solution of design and operational problems connected with the 

 strength, speed, and motion of ships at sea and in planning model tests of seaworthiness. 



SOURCES OF DATA 



WEATHER BUREAU DATA 



Wave heights and periods from the Weather Bureau records are presented in Tables 1 

 and 2. These data are visual estimates and were made every three hours by trained weather 

 observers in accordance with instructions prescribed by the U.S. Weather Bureau. 6 Only one 

 quantitative value for wave height and one for wave period were reported each time the sea 

 was observed. These data cover a period of about six years and were made from weather ships 

 at ten ocean stations, located as shown in Figure 1. 



Figure 1 - Locations of Ocean Stations 



*The "characteristic" wave height is the average height of the larger well-defined waves. See the discussion 

 under "Sources of Data" for a more specific definition. The term "characteristic" height should be differentiated 

 from "significant" height. The latter term has a precise mathematical definition, the former does not. 



