A related object of {TAIL ~ the invention} is to have the last step in {HEAD ~ the series} have a simple recess aft of it to thereby minimize wetted area resistance 
A related object of { TAIL ~ the invention } is to have the last step in { HEAD ~ the series } have a simple recess aft of it to thereby minimize wetted area resistance
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH