Table 15 



Isles of Shoals Breakwaters 



Isles of Shoals, N.H. and Maine 



Date(s) Construction and Rehabilitation History 



1821- Two rubble-mound breakwaters were constructed between Malaga, Smutty- 

 1904 nose, and Cedar Islands (Figure 17). Approximate lengths of the 

 Malaga Island to Smuttynose Island and Smuttynose Island to Cedar 

 Island breakwaters were 150 and 650 ft, respectively. 



1913 A 530-ft-long rubble-mound breakwater was constructed between Cedar 

 Island and Star Island using 34,000 tons of stone at a cost of 

 $39,000. 



1929 The Cedar Island to Star Island breakwater was repaired. 



1955 A section of the Cedar Island to Star Island breakwater (350 ft long 

 and adjacent to Star Island) was repaired placing armor stone 

 weighing 5 to 11+ tons and resetting of displaced stone. The design 

 section (Figure 17, inset) called for a +14 ft mlw crown elevation, a 

 10-ft crown width, and slopes of 1V:1.5H and 1V:1H on the sea and 

 harbor sides, respectively. Total cost was $34,900 for placing and 

 resetting 1,640 and 1,140 tons of stone, respectively. 



1967 The Cedar Island to Star Island breakwater was inspected and found to 

 be in poor condition. Plans and specifications were prepared for 

 repairing a 500-ft section adjacent to Star Island. But, due to 

 contract bids substantially above the Government estimate, no 

 contract was awarded. The plans show the breakwater to be approxi- 

 mately 650 ft long with a 200-ft dogleg section adjacent to Star 

 Island, apparently adding 120 ft to the original length . Existing 

 center-line elevations were typically from +9 to +13 ft mlw along the 

 proposed repair section. 



1974 About 575 ft of the Cedar Island to Star Island breakwater, adjacent 

 to Star Island, were repaired using 6- to 10-ton stone. Prior to 

 repair, typical center-line elevations varied from +6 to +10 ft 

 mlw. The stone was placed to an elevation and top width of +15 ft 

 mlw and 20 ft, respectively. Slopes were 1V:2H and 1V:1.5H on the 

 sea and harbor sides, respectively. In addition to 14,000 tons of 

 new stone, displaced stone on the harbor side was used in 

 reconstructing the lower portions of the breakwater. The repair cost 

 was $665,000. 



1983 Visual inspections of the Cedar Island to Star Island and Cedar 



Island to Smuttynose Island breakwaters indicate the former was in 

 good condition, while the latter was in fair to poor condition with a 

 significant amount of damage along its midsection. 



1986 Present conditions of the breakwaters are not known. 



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