The inventive structure includes a tunnel that defines {TAIL ~ a concavity} formed in {HEAD ~ a hull} of the watercraft 
The inventive structure includes a tunnel that defines { TAIL ~ a concavity } formed in { HEAD ~ a hull } of the watercraft
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH