Hogging and sagging

In solid mechanics, structural engineering, and shipbuilding, hogging and sagging describe the shape that a beam or similar long object will deform into when loading is applied.

During her three years in drydock, the center keel blocks were gradually shortened, allowing the hog to settle out.

Additionally, the diagonal riders specified in her original design to resist hogging, which had been removed in an earlier refit, were restored.

[3][4] During loading and discharging cargo, ships bend (hog or sag) due to the distribution of the weights in the various holds and tanks on board.

The amount of deflection varies in accordance with the beam's stiffness, the span between supports, and the load it carries.