Each tapered tunnel section extends from {HEAD ~ the propeller section} to a tunnel opening through a hull of {TAIL ~ the vessel} 
Each tapered tunnel section extends from { HEAD ~ the propeller section } to a tunnel opening through a hull of { TAIL ~ the vessel }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL