"The keel corresponds with the backbone of your bodies. At the forward end of it is the stem, shaped as you see in the sheer plan. At the after end is the stern-post; and these three parts form the profile of the vessel. Between them are the timbers, or ribs, curved as required by the shape of the hull. To the timbers, the stem and stern-post, the planking, or outer skin of the ship, is fastened. If you were to build a canvas canoe, you would make a frame such as I have described. The cloth part would correspond to the planking.
"But, besides the principal parts I have mentioned, of course there is a vast number of other parts, whose names you could not remember if I gave them to you. I shall add only a few of the principal ones. The timbers—I use the word in its technical sense—are set up about three feet apart, sometimes a little more, and sometimes a little less. The lower end of each is fastened to the keel, and of course each timber has to be shored up, and carefully secured in its proper position.
"The timbers are at right angles with the keel, and in large vessels are formed of several pieces. Across the keel is laid the floor timber, which is the connecting link between the pair of ribs. In the middle of the ship, the floor is nearly flat; but near the stern-post the timbers strike the keel at an acute angle, and in the same manner at a less angle at the bows.
"Above the floor timbers is laid the keelson, which is a large and strong timber a foot square or more in large vessels. These pieces are fitted together, and bolted to the keel through the timbers. The sharp angle at the stern is filled with solid wood. As you have seen, the floor timbers are parts of the ribs," continued the principal, pointing to a diagram of a full rib. "The next two sticks, forming the sharpest bend in the timber, are the futtocks, above which are the top timbers and the lengthening pieces. The plankshear is placed on the top of the timbers, extending from bow to stern, even with the upper deck, if there is more than one.
"Large ships have two, three, and even four decks. Fastened to the timbers are pieces called shelves, upon which rest the beams or timbers extending across the ship, upon which the decks are laid. In the corners, where the beams join the ribs, are placed the knees (timbers like brackets) in which the angle is formed by the natural growth of the wood. Of course all these pieces are bolted together in the strongest manner.
"The timbers next to the stem are the knight-heads. They extend upwards higher than the tops of the other ribs, and assist in the support of the bowsprit. In the keel, stem, and stern-post, a rabbet, or triangular groove, is cut out, into which the planks are extended. The first course of the planking, next to the keel, whether composed of one or many pieces, is called the garboard streak. This word is often written strake. The other word is more commonly used in this country.
"The next coarse above the garboard streak is the bilge streak, which may consist of several widths of plank. Above there are the wales, and still higher the shear streaks. Some of these terms are applied to the parts of the ship as localities. The bilge is where the sharpest bend comes in the hull; the wales are the sides near the load line.
"I have tried to give you a general view of ship-building, with a few of the more important technical terms, some of which most of you have learned before. As I have said, we shall not use all these pieces in building the boat. For example, a false keel is put under the true keel of a ship. It is a timber of the toughest wood, from four to six inches thick, which is bolted to the keel after the keelson is secured. It is but lightly fastened, for it is intended to come off, if the vessel strikes a shoal, and thus allow the true keel to slide off. We shall not need this addition, unless we require it to increase the depth of the keel. In that case, it would be better to have the part corresponding to the false keel made of lead or iron, and then it will serve as so much ballast.