Page:Popular Science Monthly Volume 92.djvu/179



OW many ships could be saved for the world's commerce if there were means immediately available to plug ugly holes in their hulls, caused by torpedoes, mines, explosive shells and collisions? This is the question which confronted a Wisconsin inventor and he straightway set about to answer it by inventing a metal apron which can be rolled up and carried on the ship's deck and immediately lowered to plug a hole torn in the hull.

The apron consists of a series of bulb tee irons such as are used for deck beams in ships or as a part of the steel framework in large buildings. The irons are held together by means of flexible metal strips bolted to their flanges. Between the metal strips and the angle flanges are strips of heavy tar paper or rubber compound, to make the apron waterproof when it is placed over the hole.

The flexible metal strips which hold the bulbs together permit the entire apron to be rolled up like a carpet and to be carried on the ship's deck on a small wheeled carriage. When a hole is stove in the ship's side, the apron is rolled to the nearest derrick, which may be the mast boom or a small steam winch placed along the side for the purpose. The apron is unrolled and lowered

into the water and down to the hole, where the inrushing water sucks it into contact with the hull. A flexible rubber or canvas pipe about eight inches in diameter is attached to the side of the apron. It comes into contact with the ship's hull and extends clear around the contour of the apron. This pipe is filled with air pumped from machinery on board, so that the apron fits the side of a ragged hole so snugly that water can not rush in around the edges.

To locate the hole in the side, two heavy hooks are first lowered by hand and caught in the front and rear projecting sides of the hole. A third and heavier hook is then lowered midway between the first two and it is made fast to the top edge of the hole. The guy rope holding this hook is firmly attached to the deck and the apron slides down the rope until notches on the supporting sling are brought up against similar notches in the upper end of the hook bar. When these notches meet, the apron's downward course is halted directly over the hole and the inrush of the water draws it securely against the hull.

It is doubtful whether the operation would be so simple if the vessel was moving. Moreover, if the hole torn in the hull were of great size, no such plugging device could keep out the water.