When the chamber is filled with sufficient air, {TAIL ~ the rearward section} becomes buoyant and pivots to {HEAD ~ its floating position} 
When the chamber is filled with sufficient air , { TAIL ~ the rearward section } becomes buoyant and pivots to { HEAD ~ its floating position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD