The invention relates to a marine load raising and lowering system for use on a vessel, comprising: i. a first winch comprising first driving means for raising or lowering a first cable from the first winch; ii. a second winch comprising second driving means for raising or lowering a second cable from the second winch; iii. operating means connected to the first and second driving means of respectively the first and second winch for synchronising the driving means so as to perform synchronous raising or lowering of the first and second cable; iv. a load connector; wherein the first and second cable are both connected to the load connector with a respective terminal end of the first and second cable, wherein the system further comprises a first tension equalizing mechanism adapted to equalize the tension in the first and second cables, said first tension equalizing mechanism having interconnected first cable-engaging members to engage with the first and second cable, wherein said first cable-engaging members are movable relative to a first reference structure to be mounted on the vessel, and wherein said first tension equalizing mechanism is configured to move the first cable-engaging members under the effect of a difference in tension in the first and second cable so as to equalize said tensions.