Ship Building by
Lieut. J. A.
Few people who are not sailors at all realize what a wonderful thing a
ship is, and of how many different parts one is made up.
In the first place, a model of the proposed vessel has to be made. The
model is an American invention. Formerly what was known as the draught
of a ship took the place of the model. In the draught the proposed ship
was represented on paper from three points of view. The first gave a
complete view of the side; the second, or body plan, showed the breadth,
having described on it every timber composing the frame of the ship;
lastly came the horizontal plan, showing the whole as if seen from
above. The model is much simpler than the old-fashioned draught. It is
simply a miniature ship.
Once having a perfect model, the good ship-constructor feels that half
his battle is already won. It may be as well here to mention the fact
that, as a rule, the length of a ship is five times her greatest breadth
of beam; her depth two-thirds of her breadth. Steamers are longer in
proportion than sailing vessels. This is on account of the extra speed
to be attained, even at the expense of strength.
After the model has been approved, the building of the ship begins. Most
of our ships are now built of wood from the South, where, since the
war, entire forests can be bought for a song.
The keel of a ship has been likened to the backbone of a man, running,
as it does, from stem to rudder. It consists of several timbers scarfed
or pieced together, and under it is the shoe, a kind of second keel, but
differing from the keel proper in that it is only loosely joined to it,
whereas the keel is bolted to the ship's bottom through and through. The
reason for this is that in case of grazing a rock a vessel having a shoe
will, in most cases, part with the shoe, thus saving the keel, and
escaping without serious injury. Corresponding with the keel outside is
a set of timbers within the frames, known as the keelson. On each side
of the keelson are assistant-keelsons to give greater strength.
On the after-end, and morticed into the keel, is the stern-post, another
important timber, all the after-part of a ship curving gracefully toward
this post. The rudder-stock works on the stern-post, which performs the
double duty of supporting the after-timbers and the rudder.
Spaces are purposely left between a vessel's frames for "salting down."
Sometimes this salt can be seen oozing out of her sides after a long
voyage. Two hundred hogs-heads of salt is not an unusual quantity for an
ordinary-sized ship. It is the only thing that will prevent what is
known as the "dry-rot" from attacking her timbers.
As a rule, every wooden vessel's ribs are of oak, and, for greater
strength, preference is given to the best qualities of live-oak. As a
ship's side curves, her outside planking has to be forced into place,
and for the short curves near the bows and stern, the planks have to be
steamed, and bent on while moist, as otherwise they would crack and
split in the process. After these outside planks are all on, the calkers
begin their work, which consists in filling in the spaces between the
planks with oakum, mallets and calking-irons being used for this
purpose. These seams are afterward covered with pitch.
In order to prevent barnacles from injuring a ship's bottom, sheathing
is put on. This usually consists of a composition of zinc and copper,
and covers all parts of a vessel exposed to the action of the water.
In Longfellow's beautiful poem, "The Building of the Ship," the reader
is led to infer that the masts are "stepped" (i. e., put in) before
the launching occurs. But practically a ship is first launched, and then
shears are rigged, and she is fitted out with her spars.