The 2570 dwt tanker Flandriya collided with a fishing vessel near the Neva Gate, St. Petersburg.   The tanker alerted the fishing vessel that it was approaching, but it could not avoid the collision.   The tanker was unable to stop due to the strong river current while the fishing vessel had become disabled due to its propeller fouled by nets.  The fishing vessel was pulled under the starboard bow sending the 3 crew on the fishing vessel into the water.  Reports state 1 crewman was rescued while 2 others are missing.