Often found on boats or ships where a line runs through it or provides an attachment point, a pad eye is a flat metal plate with a projecting loop or ring, made all in one piece—often bolted or welded to the deck or hull.
Pad eyes are also used in oil & gas projects to assist in the purpose of lifting. Lifting is done with the help of a D-shackle or sling, which fits into the hole of the pad eye. There may be one or more circular plates (cheek plates) welded around the hole.
The basic purpose of a pad eye is to provide a point to which a rope or wire rope can be fastened, directly or through a shackle. Pad eyes are one of the smallest and most universally used structural items in the maritime and oil & gas industry.
Though they seem simple in concept, pad eyes vary quite a bit in their geometry, depending on what they’re being used for. When used for lifting, they’re also known as lifting lugs.