Abstract: A subsurface buoy loading system for offshore oil gas production from production wells in the sea bottom. One or more flexible risers lead from the respective production wells to a submersible buoy adapted to be fitted to a complementary loading vessel in order to transfer petroleum products from the production wells via the loading buoy to the cargo space in the vessel. When not carrying out loading operations the loading buoy is descended down into an equilibrium position in the body of water. In the loading vessel the buoy is fitted into a rotatble turret seat located in a downwardly open tunnel in the ship hull. The rotatable turret seat is positioned at such a level that the top side of the buoy, when in the loading position, is situated above sea level. The riser or risers extend through a vertical shaft in the buoy and are attached to the top of the buoy. The rotatable turret seat supports pipes communicating between the risers and a receiving pipeline system in the vessel.