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