Extension 41 is comprised of {TAIL ~ four separate small pipes} which terminate at {HEAD ~ points} 43, 44, 45 and 46, to correspond to boat locations in tube 37 
Extension 41 is comprised of { TAIL ~ four separate small pipes } which terminate at { HEAD ~ points } 43 , 44 , 45 and 46 , to correspond to boat locations in tube 37
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH