FOULING OF SHIPS' BOTTOMS 



221 



That this is due not so much to the actual effect of cruising as to the fact that such 

 boats are not in harbor sufficiently long to accumulate heavy growths is seen by 

 comparison of this diagram with those given in Figures 25 and 26. 



PERCENTAGE OF SHIPS IN EACH GROUP 

 0 10 20 30 40 50 60 70 80 90 100 



TIME 0-3 

 IN 



MONTHS 4-7 

 SPENT 



IN 8-11 

 CRUISING 



12-15 



10 i 



imMmmmmmmmm 



"41 



25 



mmm 



DnO FLIGHT 

 F0UL1N6 FOULING 



MODERATE 

 FOULING 



HEAVY 

 FOULING 



Fig. 27. — Relation between time at sea and amount of fouling 



In Figure 28 is shown a combination of Figures 26 and 27, indicating a more 

 accurate relationship between cruising and fouling. As indicated, this table shows 



PER CENT 0FT0TAL NUMBER OF SHIPS IN EACH CLASS. 

 0 10 20 30 40 50 60 70 80 90 100 



* 5-29 

 to 



I 30-59 

 z 



£ 60-79 

 k 80-89 



90-94 



o 95-98 



luu 



h 99-100 

 z 



u4 

 O 



10 



CLEAN 



LIGHTLY FOULED 



MODERATELY FOULED 

 HEAVILY FOULED 



Fig. 28.— Relation between the amount of fouling and the per cent of total time since last dry docking spent in cruisins 



