Abstract: A device for securing a hatch cover has a locking strap pivotally attached at one end and adapted to overlap adjacent end portions of trough hatch covers. The locking strap has a free end engaged by a locking bar which pivots at right angles thereto. The locking bar is part of a unit or module which includes a shackle and a latch hook for holding the locking strap. The shackle is pivotally attached to the locking bar and is weighted with ballast to always be disposed in a vertical position for locking. The latch hook is also weighted and allowed a small amount of rotation to compensate for wear of the sealing gaskets to insure continuous locking engagement between the shackle and the latch.