Closing devices specifies are parts of small hatchways (e.g. access hatchways, hatchways for emergency escape) and flaps (e.g. ventilator flaps). They essentially consist of eye bolts and bow- or toggle nuts. They serve to procreation the contact pressure between cover and coaming or frame, which is necessary for thightness of hatchways of flaps.
DIN 83407:1996 history
2018DIN 83407-1:2018 Closing devices (fasteners) and fork plates for ship's equipment - Part 1: Made of steel
1996DIN 83407:1996 Closing devices (fasteners) and fork plates for ship's equipment