Abstract: A lift system for raising and lowering a load including a rigid platform, four spaced fixed supports positioned around corners of the platform, and a power source connected to a first of the supports. First and second inextensible lines are each preferably fastened at one end to a third support diagonally opposing the first support, and at another end thereof to the power source. The first line preferably extends from the power source to the third support, passing to a plurality of four pulleys each attached to a corner of the platform and over a pulley attached to the second support. The second line preferably extends from the power source to the third support, passing to a plurality of four pulleys each attached to a corner of the platform and over a pulley attached to the fourth support. The lift system produces a mechanical advantage of four.

Abstract: A load hoisting system for raising and lowering a load. A first line supports a rigid beam with unequal mechanical advantages on either side of the load. A second line supports the same rigid beam with mechanical advantages on either side of the load that are, in total, equal to those on the first line but with a ratio of mechanical advantages unequal to the ratio of mechanical advantages of the first line. One end of each line is fastened to a fixed support and the other ends of the two lines are drawn at the same rate by a power source, which system eliminates all axial rotation of the beam. The system may be applied to both ends of a long load by drawing of all lines in synchronism, advantageously being applied to lift both ends of a boat.