192 



HARBOUR CONSTRUCTION. 



The breaking weight of a four-ply band, 5 inches wide, of 

 good jute sacking, such as cement-bags are generally made of, 

 is about 10 cwt. ; so, allowing a proper margin of safety for 

 working loads, the number of bands required to carry a bag of 

 concrete of any given weight can be readily determined. Thus, 

 assuming the bands in the illustration to be of the dimensions 

 named, they would just break with a load of four tons. 



FIG. 35. Type section of breakwater formed entirely of mass concrete. 





- K> - I ',' '- ' 9 % ;5* V -.* ' jj . ... ' ". ' '.* ': ' '* j v 



~~^ ^iii!jj^jj^^S^M 





FIG. 36. Fraserburgb breakwater. 



In Fig. 35 a type section of breakwater is shown constructed 

 entirely on the monolithic system. Fig. 36 shows a section of 

 the breakwater at Fraserburgh, which was constructed on the 

 same system, but with a base of bag- work. 



Inasmuch as it is almost impossible to avoid leaving some 



