there is provided a loader which is well suited for lifting heavy weight blocks and which is thus particularly advantageously usable in the assembling of blocks for building a ship . the loader body includes at least one beam arranged in a horizontal plane , and a plurality of separate pulley means are directly or indirectly mounted on the loader body in such a manner that these pulley means are arranged fixedly or movable to adjust the distance therebetween , whereby even when the center of gravity of a block is not in alignment with the center of the loader , the block can be lifted easily .