upon release of spider buoy 44 for indicating the location of spider buoy 44 when it is submerged a retainer plug member 58 is secured to the lower end of chain 52 it abuts a stop 100 adjacent the upper end of spider buoy 44 to maintain chain 52 in a taut relation for docking of buoy 44 mooring chain 52 is lifted and tensioned by a jack assembly 57 and winch assembly 56 for further details reference is made to aforementioned u s pat no 5 306 186 columns 8 10 risers 60 which extend to wells or manifolds on the sea floor are carried by spider buoy 44 they include a coupling 62 which is connected to a mating coupling 64 on turret 32 mating couplings 62 and 64 are well known in the art and may be purchased from m i b international limited of coventry england or fmc corporation of houston tex workman 48 standing on platform 46 above sea level 16 connects couplings 62 and 64 upon docking of spider buoy 44 the connection is facilitated because it is performed above the sea not in the sea water suitable piping 66 extends to manifolds 30 and swivel stack 26 from mating couplings 62 64 for the supply of product to holds in vessel 10 spider buoy 44 is formed so that it has buoyancy it may include polyurethane foam material or it may have steel enclosed air chambers twelve anchor legs are preferably provided which comprise anchor chains 68 designed and arranged in an array spaced from.