System for extraction of heated heavy fuel oil from an elongated heavy fuel oil storage tank comprising: a convection shield with closed top and sides and a substantially open bottom, wherein the convection shield is mounted with a clearance between the bottom of the storage tank and the lower edge of the convection shield to allow for entry of heavy fuel oil into the convection shield through the open bottom, a heating element arranged inside the convection shield for heating the heavy fuel oil inside the convection shield, a fuel suction line arranged inside the convection shield for extracting heated heavy fuel oil from the heavy fuel oil storage tank, characterized by an elongated inflow convection shield comprising: a closed upper part comprising a top and sides, a lower part, with openings for throughflow, positioned at the same height, or lower, as the lower edge of the convection shield to allow entry of heavy fuel oil into the inflow convection shield through the lower part, wherein the inflow convection shield is connected to the lower edge of the convection shield, sharing a common interior allowing flow of heated heavy fuel oil from the inflow convection shield to the convection shield, and wherein an inflow heating element is positioned along the length of and inside the inflow convection shield for heating the heavy fuel oil inside the inflow convection shield, and wherein the inflow convection shield extends along the bottom of the storage tank in its longitudinal direction. a convection shield with closed top and sides and a substantially open bottom, wherein the convection shield is mounted with a clearance between the bottom of the storage tank and the lower edge of the convection shield to allow for entry of heavy fuel oil into the convection shield through the open bottom, a heating element arranged inside the convection shield for heating the heavy fuel oil inside the convection shield, a fuel suction line arranged inside the convection shield for extracting heated heavy fuel oil from the heavy fuel oil storage tank, characterized by an elongated inflow convection shield comprising: a closed upper part comprising a top and sides, a lower part, with openings for throughflow, positioned at the same height, or lower, as the lower edge of the convection shield to allow entry of heavy fuel oil into the inflow convection shield through the lower part, wherein the inflow convection shield is connected to the lower edge of the convection shield, sharing a common interior allowing flow of heated heavy fuel oil from the inflow convection shield to the convection shield, and wherein an inflow heating element is positioned along the length of and inside the inflow convection shield for heating the heavy fuel oil inside the inflow convection shield, and a closed upper part comprising a top and sides, a lower part, with openings for throughflow, positioned at the same height, or lower, as the lower edge of the convection shield to allow entry of heavy fuel oil into the inflow convection shield through the lower part, wherein the inflow convection shield is connected to the lower edge of the convection shield, sharing a common interior allowing flow of heated heavy fuel oil from the inflow convection shield to the convection shield, and wherein an inflow heating element is positioned along the length of and inside the inflow convection shield for heating the heavy fuel oil inside the inflow convection shield, and