IMPROVEMENTS IN SHIP- BUILDING
Year: 1857

page_text: PROVISIONAL SPECIFICATION left by James Hamilton at the Office of
the Commissioners of Patents, with his Petition, on the 21st December
1857.
I, JAMES HAMILTON, of Liverpool, in the County of Lancaster, Shipwright,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN SHIP-
BUILDING," to be as follows:-
This Invention relates mainly to an improved manner of constructing the
keel, keelsons, and lower portions of a vessel by so arranging the timber and
bolts used to connect the various parts that a much greater amount of strength
may be obtained than by the method now in use, and that is accomplished
without the use of timber of the large dimensions now required for the pur-
pose; and in making a provision against the dry rot in vessels by forming
shallow channels or grooves in the surface of the timber in the direction of
the grain of the wood, on all or a portion of the surfaces of the timbers,
planking, and ceiling which are in contact; by which arrangement air cells
or passages are formed throughout the whole structure, through which air,
gasses, or fluids may be forced if it should be deemed advisable.
To apply this Invention to a vessel of, say 150 feet keel:-To form
the keel take any convenient number of pieces of timber which are half the
thickness and as deep as the keel required, say two feet deep by one foot thick,
on the sides of the ends form scarph joints (say about eight feet long); having
thus formed two vertical keel pieces of the required length, rabbet, or groove
and bolt them together sideways, observing to arrange them so that they will

page_text: break joint, and that none of the scarphs are near the centre of gravity or
pump well. The extremities of the keel are formed with single logs, and by
preference the foremost piece of the keel is of such a shape as to form the
forepart of the keel and the lower portion of the stem. This piece is attached
at the foremost double keel, extending upwards to a certain height, finishing
with a thwart ship flat scarph of, say eight feet long, in order to receive the
upper part of stem.
The log forming the after part of the keel is also attached to the portion
of the keel formed by the side pieces by a tongued joint. When the whole is
securely fixed together by means of transverse pins, bolts, or screw bolts,
having previously made good the joint by introducing a metal tongue plate at
the centre, right fore and aft, in order to make all tight between the edgo
pieces, then caulk in lead, oakum, &c. Then clap on a false keel (of, say
from four to six inches thick), and secure it to the keel by short bolts passing
up through the edgo pieces forming the keel. Then place the dead-wood log
aft, and form it of sufficient thickness to be enabled to dispense with the
garboard strake for a distance of, say about twenty-four feet from the stern-
post forward. Then place other dead-wood over it to give the required
height, finishing with a "skegg" (or wood knee), running up to the lower
transom. The dead-wood forward is put in as usually done. An inbreast is
applied above the keel, say four or six inches thick, and the wholo breadth of
keel, in order to steady the seats of the floorings. The improved lower kelson
is then laid above the floors, extending fore and aft as far as required.
This improved lower kelson is formed by two lengths of logs scarphed
together endways, and laid together sideways, in the same way the main keels
are constructed, taking care to break jointing scarphs or abuttings in the
same way. By this arrangement two bolts can be passed through each floor
timber and right down throughout the keel, in place of ono now used. On
the top of the lower kelson a stout log or logs are laid (singly), which
covers by centreing the joints of the lower kelson, and sufficiently large
to allow of bolts being driven diagonally through it and the lower kelson;
each alternate bolt being so driven that they are crossed or reversed to each
other, and these crossing, or dingonal bolts are so introduced that they pass
through the lower kelson clear of the floorings, and are there riveted;
or these bolts may be so formed with scrowed points to receive a nut, if pre-
ferred. The whole is then covered on the top with a chafing or hog piece.
In addition to the lower limber passages now used, upper limber passages for
the water to the pump well are formed over the flooring seats on each side of
the kelson. These upper limber passages are covered by loose planks or

page_text: timber covers which fit into rabbets formed into the timber foot logs, with an
extra piece of thick stuff entering the two lower ones on the surface, and
bolted diagonally on the lower pieces for further strength. It is preferred to fit
the limber covers so that they will slope upwards from the timber foot logs
and rest against the sides of the lower kelson.
On the outer and inner sides of all the timbers one or more shallow
channels or grooves are formed in the direction of their length. The other
planking and ceiling timber is also grooved in the direction of the grain of
the wood, to form one or more shallow channels on the surfaces which are
in contact with the timbers, so that a complete system of air cells or passages
will be formed throughout every timber in the ship without material injury to
the strength of the vessel, thereby obtaining a sure preventive against the
dry rot.