waves from northerly through easterly to southerly directions although partially sheltered 

 by shoals to the east (Fig. 21). 



(b) Wave Conditions. FuUy exposed to deep water -generated waves from north 

 through east through southeast, except for partial shelter afforded by Flat Ground and 

 Salvages shoals. Heaviest seas are from the northeast through east with maximum wave 

 heights occurring during December, January and February. 



(c) Currents. Tidal currents at site are reported as negligible. 



(d) Winds. Strongest and most dangerous winds from northeasterly through 

 easterly direction. FuUy exposed to easterly, northeasterly and northerly gales. 



(e) Storm Surge and Tides. Approximate extreme high and low tides recorded 

 for the area are 12 feet above MLW and 3.5 feet below MLW. Mean normal tidal range, 8.6 

 feet; mean spring tidal range, 10.0 feet. 



(f) Littoral Transport. No data available. 



(g) Water Depth at Structure. Varies from 25 to 75 feet at MLW. 



(h) Foundation Conditions. No data available. U.S. Coast and Geodetic Survey 

 Chart No. 243 (Fig. 21) indicates hard, rocky bottom conditions at the breakwater. 



(5) Structural Features. 



(a) Dimensions of Basic Structure (U.S. Army Engineer Division, New England, 

 1972). 



1 Length. Original project proposed a continuous breakwater 9,000 feet 

 long, extending from Avery Ledge, 3,600 feet (southern arm) to an angle at Abner's Ledge, 

 then 5,400 feet (western arm) toward Andrews Point. As buUt, the substructure of the 

 southern arm and the first 2,500 feet of the western arm were completed to approximately 

 MLW. A total length of 922 feet of superstructure was completed of which 720.6 feet was 

 on the southern arm and 201.4 feet on the western arm (Fig. 21). 



2 Side Slopes (Fig. 22). 



a Seaward Slope. 1 on 1 to elevation 8.6 feet; than 1 on 2 to elevation 

 —25 feet; and 1 on 1 below elevation, —25 feet below MLW. 

 b Shoreward slope. 1 on 1. 



3 Crest Elevation and Width (U.S. Army Engineer Division, New England, 

 1970) (Fig. 22)7 



a Completed. 22 feet above MLW (13.4 ft. ^ove MHW, and 20 ft. wide), 

 b Incomplete. Core built up generally to MLW. 



(b) Unusual Features. Workmanship and craftsmanship exhibited in breakwater 

 superstructure of uniform -cut granite blocks laid flat and in horizontal courses (Fig. 23). 



(6) Design Data. 



(a) Design Conditions. Data not available. 



(b) Model Study. None. 



(c) Instrumentation. None. 



45 



