The Boys' Book of Submarines

by A. Frederick Collins; Virgil D. Collins

FIG. 12. THE NOSE AND TAIL BLOCKS.

Now cut off a piece of brass tube which has an inside diameter of ⅛ inch and an outside diameter of ¼ inch and force it into the hole in the tail block; this tube forms the bearing for the propeller-shaft.

Cut out a disk of brass 1¼ inches in diameter and ¹/₁₆ inch thick; drill a ⅛-inch hole through the center of it for the propeller-shaft to pass through, and three ⅛-inch holes at equal distances apart near the edge, as shown at C, so that it can be screwed to the tail block. The purpose of this disk is to keep the packing in the stuffing box. See [Fig. 12].

The next thing to do is to cut off two brass rods each ⅛ inch in diameter and 16½ inches long and fit the ends of these into the lower holes in the blocks; and then cut off two more brass rods 17 inches long and set these into the upper holes. Bend these latter rods out a little until the faces of the blocks are parallel with each other, and you will have a substantial framework on which to fasten the skin of the hull.

The skin, as the sheets or plates which form the hull are called, is made of sheet tin, and to cut the tin you should have a pair of tinner’s shears.

You will need seven strips of tin altogether: one for the bottom and three for each side. The sizes and shapes of these strips are shown in [Fig. 13]. The widest strip is used for the bottom of the hull; bend up the edges along the dotted lines, then punch eight holes in the ends—these are shown by the little crosses—and screw it to the nose and tail blocks with flat-headed wood screws.

Next punch holes in and screw one of the lower strips to each side of the nose and tail blocks, with the hollow curved edge down and lapped over the turned-up edge of the bottom strip; punch and screw on each of the middle strips, with its lower hollow curved edge over the top of each of the lower strips; and then punch and screw on the top strips.

When you have the bottom and all of the side strips screwed on, each one will lap over the next lower one ½ inch and fit snugly up to it, and at the same time they will all curve gracefully.