The foremost edge of the hydrofoil comprises a slot covered by a continuously adjustable gate for controlling {HEAD ~ the overall drag} imposed by {TAIL ~ the turbine} 
The foremost edge of the hydrofoil comprises a slot covered by a continuously adjustable gate for controlling { HEAD ~ the overall drag } imposed by { TAIL ~ the turbine }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL