Making A Mysterious Stopper
To make your ship-in-a-bottle model even more mysterious, you can cap the open mouth of the bottle with a novel unremovable stopper. It consists of a wooden plug having a wooden pin passing through its center and a short piece of string running through both plug and pin. In appearance, it seems like an impossible freak of construction, but by following the simple steps outlined in Fig. 6, the model maker should have no difficulty in assembling one. Turn a wooden plug about 1/16 in. smaller than the opening and about 3/4 longer than the neck. Make the pin wedge-shaped and also tapering in width. Cut a hole for it in the plug so that it will slip in without hitting the bottle. It should fit the hole in the plug as accurately as possible. Put the pin in the hole and drill a small hole - not more than 1/16 in. - through both. Twist a short piece of string quite tightly the way it was originally spun, catch it in the middle, bring the two ends together, and let it twist on itself. Measure from the loop end about twice the diameter of the plug, tie a knot, and cut the string. It should be large enough to fit the small hole fairly tight.
Now take a piece of stout cord such as braided fishline and thread it through the loop of the other cord as you would thread a needle. Draw the ends even and slip them through the small hole in the plug and pin, but do not pull the short string through. Next push out the pin, and put pin and plug in the bottle (see Fig. 6). Lay the bottle on its side with the larger end of the hole in the plug down. If you have made the pin correctly, it will hang with the point up. Slowly pull the string and shake the bottle, drawing the pin into the hole. When the pin is in place, pull the short string through as far as the knot will allow and saw the line back and forth until you have cut through the loop. Pull the line out, leaving the short string extending through plug and pin to mystify all observers.