The MacAdam shovel, sometimes known as the Hughes shovel, was the brainchild of Sir Sam Hughes, Canadian Minister of Militia and Defence from October 1911 until November 1915, who is best known as the man responsible for the Ross Rifle fiasco.
The shovel, which Hughes modelled after after a Swiss invention and patented under his personal secretary's name, was designed to serve a dual purpose in trench warfare. In addition to its primary use as a digging tool, the shovel featured an egg-shaped hole in the steel blade. The purpose of this hole was to allow soliders to sight their rifle whilst simultaneously receiving protection from enemy gunfire. Unfortunately, this hole made the shovel highly inefficient for digging, while the blade reportedly provided no protection to soliders hiding behind it — the metal being too weak to stop a bullet.
As if these shortcomings were not enough to spell doom for this misguided invention, the handle was made of iron. The end result being that the final product was considered too heavy for any practical use, weighing in at over 5 pounds.
Despite these obvious faults, Hughes had confidence in his invention and over twenty thousand were ordered for military use. However, it is unlikely that any of these ever actually saw combat action, and most are believed to have been eventually melted down for scrap.