Table 4. Height to draft ratios for 

 drydocked bergs 



Domed bergs (weathered, smoothed, deteri- 

 orated bergs) were the most deceptive (Table 5). 

 They penetrated the water's depths as the pin- 

 nacle bergs penetrated the air. The domed bergs 

 had an average height to depth ratio of 1:6.30, 

 by far the smallest ratio of any class of bergs. 



Table 5. Height to draft ratios for domed 

 bergs 



The assumption was made that the height to 

 draft ratios of icebergs form a continuous distri- 

 bution. Using a Kruskal-Wallis one-way anal- 

 ysis of variance technique, Welch (1975), the 

 hypothesis that the average ratio for icebergs was 

 not significantly different for the gross visual 

 shape classes was tested. This resulted in the 

 conclusion that, for the sampled icebergs, there 

 was no significant difference between classes. For 

 summary purposes the average of the visual class 

 averages ( 1 :3.95 ) can be used as descriptive of 

 the height to draft ratio of icebergs regardless 

 of visual shape classes. 



Since one visual class was not significantly 

 different from another with respect to the height 



to draft ratio, all classes were combined and the 

 ratios were plotted against iceberg height, The 

 distribution was by no means linear and was best 

 represented by the power curve (See Figure E-3). 

 7ratio = 49.4 (Height)- 8 



The taller bergs had a narrower range of 

 height to draft ratios than the lower bergs, which 

 had height to draft ratios which spanned the 

 entire range. Icebergs with the greatest height 

 had the largest height to draft ratios. The draft 

 for tall icebergs was proportionally less than 

 for low bergs. The reasons for this were con- 

 jectured to be as follows: 



a. The tallest bergs generally had spires and 

 pinnacles which add great height with minimum 

 mass, while the lowest bergs tend to be worn and 

 smooth, having maximum mass for minimum 

 heights. 



b. The lowest bergs were worn and have only 

 the most dense ice remaining, all unconsolidated 

 ice and snow having been washed away, and most 

 voids having disappeared causing them to float 

 lower in the water. 



The height to draft ratios measured in this 

 study fall generally into three groupings; the 

 horizontal berg, the vertical berg, and the weath- 

 ered berg. The ratios are smaller (greater depth 

 for a given height) than have been presented in 

 recent work on icebergs. The domed berg has a 

 surprisingly large draft, which must indicate that 

 the underwater portion is not rounded as the top. 

 With these results it will be possible to develop a 

 better model of exactly what water layer is acting 

 on an iceberg during drift and deterioration 

 studies. 



References 



Budinger, T. F., 1960: Wind Effect on Icebergs 

 (U.S. Coast Guard, unpublished manuscript). 



Dawson, W. B., 1907 : The Currents in Belle Isle 

 Strait, Department of Marine and Fisheries, 

 pp. 1-43, Ottawa, Canada. 



Krummel, O., 1907: Handbuch der Ozeano- 

 graphic, Vol. I, Leipzig, 526 pp. 



Murray, J. E., 1968 : The drift, deterioration and 

 distribution of icebergs in the North Atlantic 

 Ocean, Ice Seminar : A conference sponsored by 

 the Petroleum Society of CIM, Calgary. 

 Alberta, May 1968. 



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