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