IMPROVEMENTS IN DAVITS FOR SHIPS AND OTHER VESSELS
Year: 1879

page_text: LETTERS PATENT to Henry Robertson, of Gosport, in the County of Hants,
Gentleman, for the Invention of "IMPROVEMENTS IN DAVITS FOR SHIPS AND
OTHER VESSELS."
Sealed the 24th June 1879, and dated the 9th January 1879.
PROVISIONAL SPECIFICATION left by the said Henry Robertson at the Office
of the Commissioners of Patents on the 9th January 1879.
HENRY ROBERTSON, of Gosport, in the County of Hants, Gentleman.
PROVEMENTS IN DAVITS FOR SHIPS AND OTHER VESSELS."
"IM-
These improvements are intended to facilitate the removal of a boat suspended
on davits from a position within board of the ship to a position outboard ready for
lowering, or the reverse, and in such manner that the boat is slewed out both ends
at once by a continuous movement. This according to one arrangement is effected
by substituting for one of the two davits of the usual form, preferably the foremost,
an improved davit formed so as to allow the boat to be removed from one position
to the other by a continuous movement in one direction of the ordinary and im-
proved davits on their axes, and both ends of the boat to reach the outboard or
inboard position simultaneously, instead of having to remove the boat by swinging
out or in one end of the boat at a time as necessitated by the use of the davits of
the usual form.
According to this first arrangement I form the davit in the shape of a crank or
ogce above the usual supports which hold it to the ship's side, so as to allow an
uninterrupted passage of the boat over the axis of this davit while being removed
from the outboard position to the inboard, or the reverse.
In order that the boat
may not come in contact at any time with this davit a bracket bar or arm of
sufficient length for the purpose of keeping them apart is made to pivot from near
the top of the improved davit, from the projecting end of which bar one end of the
boat is suspended. In order to keep this bracket bar or arm parallel to the line
of the boat's keel, and to preserve an equal distance during the removal of the boat
between the top end of the improved davit and the projecting end of the ordinary
davit from which the other end of the boat is suspended, an upright pin is made to
project above the axis of this bracket bar or arm, also above the point of suspension
of one end of the boat at the projecting end, and also above the point of suspension
of the other end of the boat at the projecting end of the ordinary davit. These
[Price 6d1

page_text: three pins are connected by a bar of iron or wood, which has three holes made in it
to fit the three pins and to keep them in the same line with one another, and all
three in a lino parallel to the keel of the boat.
The cross bar may in some instances be dispensed with, but the result would be
decreased efficiency.
The purpose of the cross bar in my Invention is not only to cause concerted
action between the davits, but also to keep the projecting end of the bracket on
ogec davit in its proper relative position while slewing.
Sometimes it might be convenient to suspend one end of the boat from this bar
instead of having a bracket.
According to another arrangement a similar motion of the boat may be obtained
by using two ordinary davits, both curved ends going in same direction, further
apart than usual, and connecting them by a cross bar, from which bar one end of
the boat might be suspended.
Instead of a movable bracket at end of ogec davit a horizontal plate might
be employed with a semicircular slot in which the pin suspending one end of boat
might travel. This arrangement could be carried out with or without the cross bar,
but I prefer to retain the bar, and to use it in combination with davits con-
structed and acting substantially in the manner and for the purposes herein beforo
described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Robertson in the Great Seal Patent Office on the 8th July
1879.
HENRY ROBERTSON, of Gosport, in the County of Hants, Gentleman.
PROVEMENTS IN DAVITS FOR SHIPS AND OTHER VESSELS."
"
IM-
These improvements are intended to facilitate the removal of a boat suspended
by davits from a position within board of a ship to a position outboard ready for
lowering or the reverse, and in such a manner that the boat is turned or slewed out or
in by a continuous horizontal movement, both ends reaching the outboard or inboard
position simultaneously, instead of having to be turned or slewed out or in one cud
at a time, as necessitated by the use of the two davits of the usual form and
arrangement. To effect this continuous horizontal movement of the boat in turning
it inboard or outboard I substitute for one of the two davits of the usual form,
and preferably the foremost one, an improved davit formed in the shape of a
crank or ogee above the usual sockets or collars which support it, so as to allow an
uninterrupted passage of the boat over the axis of this davit while being removed
from the inboard to the outboard position, or the reverse, and so as to enable both
davits to revolve together round their axes in the same direction. In order to
suspend the boat so as to be free from contact at any time with the improved davit,
and to preserve an equal distance between the top of the improved davit and the
projecting end of the ordinary davit used in connection therewith I connect them
by a horizontal bar or beam jointed to them both. The beam or bar is placed in
such a manner as to be always parallel to the line of the boat's keel, and so as to
leave the davits free to revolve on their axes as much as may be necessary for the
purpose of turning the boat outboard or in. From this bar or beam I suspend one
or both ends of the boat.
Figure 1 of the accompanying Drawings represents a side elevation of my im-
proved arrangement of davits with a boat suspended therefrom, that is, one end
from the ordinary davit, and the other end from the bar connecting the two davits.
The boat is shown in a position midway between the outboard and inboard
position. Figure 2 is a plan showing the boat in the act of being turned outboard,
the dotted lines show the position of the boat and the davits when in the outboard
position; Figure 3 is an end clevation of boat and davits in the outboard position.
A is the improved davit; B, the ordinary davit; and C, the connecting bar or beam
jointed to both. In order further to ensure concerted action between the improved
davit A and the ordinary davit B used in connexion therewith I fix to each, at a
point near the sockets in which they are supported, a short horizontal arm or
crank D at right angles to the planes in which the davits are formed. These two
cranks or arms D I connect together by a rod E hinged to them, so as to allow
them to turn in a horizontal plane as the davits A and B revolve on their axes.
The connecting rod E is bent or cranked near each end, as shown in Figure 2, so as
to clear the upright part of the davits when the boat is in the inboard or outboard
position. As before stated, both davits turn in the same direction and simul-
taneously. Instead of suspending the boat or one end of it from the above
mentioned bar or beam it might be convenient to suspend one end of it from the
projecting end of a bracket or arm supported by and pivoting horizontally from the
improved davit near its top end. This bracket I make of sufficient length to keep
the boat free from contact with the improved davit. This arrangement is illustrated
in Figure 4, which is a side elevation; F is the bracket or arm pivoting on my
improved davit A. In order to keep this bracket F parallel to the line of the boat's
keel, and to preserve at all times during the removal an equal distance between tho
top end of the improved davit A and the projecting end of the ordinary davit B,
used in connexion therewith, and from which the other end of the boat is sus-
pended, I connect the top of the improved davit A and the projecting end of the

page_text: ordinary davit B by a guide rod or bar C. In this rod are formed three holes, one
at each end to fit respectively over a vertical pin on the top of the improved davit A
and a vertical pin in or upon the projecting end of the ordinary davit B, and one
to fit over a vertical pin in the projecting end of the bracket F.
Having now described the nature of my said Invention, and in what manner the
same is to be performed, I declare that I claim,—
Constructing and arranging ships' davits in such a manner that the boat while
being turned inboard or outboard can pass uninterruptedly over the axis of one of
the davits, be it by the combination of a crank shaped davit, an ordinary davit and
a connecting cross bar, or by the combination of a crank shaped davit, a bracket
thereon, and a connecting bar, all substantially as described, and also as illustrated
in the accompanying Drawings.
In witness whereof, I, the said Henry Robertson, have hereunto set my hand
and seal, this Thirtieth day of June, in the year of our Lord One thousand
eight hundred and seventy nine.
HENRY ROBERTSON. (L.S.)