a driving shaft extending through {TAIL ~ said vessel} and inside said portion of {HEAD ~ the sleeve element}, 
a driving shaft extending through { TAIL ~ said vessel } and inside said portion of { HEAD ~ the sleeve element } ,
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH