{HEAD ~ A boat} is positioned between {TAIL ~ the mobile boat supports} and the mobile boat supports are moved inwardly on the deck to positions adjacent the boat 
{ HEAD ~ A boat } is positioned between { TAIL ~ the mobile boat supports } and the mobile boat supports are moved inwardly on the deck to positions adjacent the boat
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH