Haupt. ] 36 (Dee. 16, 
The position, extent and character of these works will depend 
largely upon the form and extent of the inner basin. Both the 
outer and inner lines should be so adjusted as not seriously to 
check the prevailing currents, nor produce shoals where they 
might be injurious ‘to navigation. 
Tur GENERAL PLAN. 
A typical plan for a breakwater which will not produce 
eddies or objectionable shoals, nor be eaten away by the 
sea, would be one composed of curves whose cusps are 
pointed in the direction of the advancing flood resultant, 
and having an inshore flank to concentrate the flood upon the 
beach channel, where it is both possible and desirable to main- 
tain one. Thecurves should have the semi-conjugate diame- 
ters equal to about one-fourth (4) of the transverse. The 
interferences resulting from this form will produce shoals 
in front of the groins, thus reinforcing them, and as the 
outer end of the breakwater is pointed so as to receive 
the flood point blank, there will be no eddy nor any abrupt 
checking of its velocity inside to cause shoaling, yet the 
flood will be freely admitted and there will be a circula- 
tion created by having the beach end open. During the ebb 
there is no interference with the main current, but there is a 
concentration of its energy upon the weaker portion of the bar. 
For an illustration of this plan reference is made to the location 
on the chart of Charleston (Fig. 1), submitted herewith. The 
jetties, U. S. J. now under contract, cover a total length 
of six (6) miles. Those projected, of but three (8) miles, :d 
the latter will make two (2) good channels, one for flood and 
one for ebb, while it is very doubtful whether the for ser 
will produce any material improvement of the entrance, but 
it will advance the general shore line and push the bar 
further to seaward. 
