IMPROVEMENTS IN BOAT DAVITS AND " DISENGAGING GEAR FOR SHIPS' BOATS
Year: 1881

page_text: LETTERS PATENT to Robert Burdes, of Sunderland, in the County of Durham,
Mariner, for an Invention of IMPROVEMENTS IN BOAT DAVITS AND
"
DISENGAGING GEAR FOR SHIPS' BOATS."
PROVISIONAL SPECIFICATION left by the said Robert Burdes at the
Office of the Commissioners of Patents on the 24th February 1881.
ROBERT BURDES, of Sunderland, in the County of Durham, Mariner.
MENTS IN BOAT DAVITS AND DISENGAGING GEAR FOR SHIPS' BOATS."
.
"
IMPROVE-
My Invention relates, firstly, to an improved construction and arrangement of
the davits used for suspending ships' boats, by which their safe launching under all
circumstances can be effected; and, secondly, to improvements in the gear by which
the boats are suspended enabling them to be disengaged instantly and safely from
the davits.
According to my Invention, the davits are constructed each with a hinge joint at
or near the level of the bulwarks, and at a certain point above this a collar grasps
the shank of the davit (which is free to turn in it), having attached to it a stay or
strut, the lower end of which is connected to a nut working freely upon a screw
fixed vertically in brackets to the side of the ship. The upper end of the screw
has fixed upon it a toothed wheel which by suitable winch gear is operated from
the deck, either working each screw separately, or the two together by a connecting
spindle. The rotation of the screws in one direction causes the nuts to travel
downwards upon their threads, and the stays or struts lower the davits (with the
boats suspended from them) over the ship's side till they project horizontally
(supported by the stays or struts), and thus carry the boat well clear of the ship
and nearer to the water ready for disengaging. The boat being launched, the
davits are brought back to their upright position by rotating the screws in the
opposite direction, the stays or struts then standing vertically. When it is.
required to swing the boat in-board or from the " chocks" out-board, it is necessary
to prevent the hinges acting, as the stays or struts do not support the davits when
swinging, and this is effected by locking the hinges by sliding sleeves, or other
Гр..

page_text: simple locking device, which renders the two parts of the davits rigid. The davits
can now be swung round in the deck sockets either by hand, or by toothed wheels
keyed on their shanks, and worked by winch gear from the deck.
The screws on ship's side may be so fitted as to be readily removed from their
brackets (and with them the stays or struts, if required) when in port so as to be
clear of damage, and can be re-shipped when leaving port.
In applying my Invention for disengaging the boat, a stanchion is fixed at each
end of the boat projecting above the "thwarts" and having a crutch shaped head,
one horn of which has hinged to it a round bolt, extending across and overlapping
the opposite horn. In the opposite horn is fitted a larger bolt having its inside
end formed with a circled "half-lap," and its outer end forming a short crank or
lever. The inner top portion of the horn containing this bolt is cut out to the
extent of the "half-lap" in length and rather wider than the diameter of the
hinged bolt, the loose end of which falls into it when it is horizontal, and the "half
lap" of the larger bolt being turned to the top side of the horn, fixes the hinged
bolt firmly, and in this position the hook of the tackle is attached to it, the boat
being securely suspended by its two ends. Along the bottom of the boat, close to
the keel, is carried in guides a bar attached at each end to one arm of a bell crank,
the other arm of which takes hold of an upright rod, the top end of which is
connected to the short crank or lever, before named, on outer end of the half-lap
bolt in the crutch horn of each of the stanchions. At a point in the bar at bottom
of boat a heavy weight is arranged to slide easily upon the bar worked by a hand
lever and links, so as to strike a blow upon a collar or stop upon the bar. This
blow forces the bar in that direction which moves the bell cranks, and they in their
turn act upon the upright rods attached to the short cranks or levers which turn
the half-lap bolts half round, when the hinged bolts having now no support fly
open on their hinges, and, the boat being free of the tackle hooks falls into the
The boat is again attached to the tackle by putting back the hinged bolts
in the horizontal position and turning the half-lap bolt half round, when the hinged
bolt is again firmly secured and the tackle hooks can be attached. The momentum
of the sliding weight when it meets the collar or stop strikes a blow that instantly
acts upon the levers and releases both ends of the boat at the same moment, and
the release can be effected before the boat touches the water, if required, as in the
case of the ship going at full speed.
water.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Burdes in the Great Seal Patent Office on the 23rd August
1881.
ROBERT BURDES, of Sunderland, in the County of Durham, Mariner. “IMPROVE-
MENTS IN BOAT DAVITS AND DISENGAGING GEAR FOR SHIPS' BOATS."
My Invention relates, firstly, to an improved construction and arrangement of
the davits used for suspending ships' boats, by which their safe launching under all
circumstances can be effected; and, secondly, to improvements in the gear by which
the boats are suspended, enabling them to be disengaged instantly and safely from
the davits.
According to my Invention the davits are constructed with a hinge joint at or
near the line of the bulwarks, and at some point above this a collar grasps the
shank of the davit (which is free to turn in it) having attached to it a stay or
strut, the lower end of which is connected to a nut working freely upon a screw
fixed vertically in brackets on the side of the ship. The upper end of the screw
has fixed upon it a toothed wheel which by suitable winch gear is operated from
the deck, either working each screw separately, or the two together by a connecting
spindle. The rotation of the screws in one direction causes the nuts to travel
downwards upon their threads, and the stays or struts lower the davits (with the
boat suspended from them) over the ship's side until they project horizontally
(supported by the stays or struts), and thus carry the boat well clear of the ship
and nearer to the water ready for disengaging. The boat being launched, the davits
are brought back to their upright position by rotating the screws in the opposite
direction, the stays or struts then standing vertically. When it is required to
swing the boat "in-board," or from the chocks "out-board," it is necessary to
prevent the hinges acting, as the stays or struts do not support the davits when
swinging, and this is effected by locking the hinges by sliding sleeves or other
simple locking device, which renders the two parts of the davits rigid. The davits
can now be swung round in the deck sockets either by hand or by toothed wheels
keyed on their shanks and worked by winch gear from the deck.
The screws on ship's side may be so fitted as to be readily removed from their
brackets (and with them the stays or struts if required) when in port, so as to be
clear of damage, and can be re-shipped when leaving port.
In applying my Invention for disengaging the boat a stanchion is fixed at each
end of the boat, projecting above the "thwarts" and having a crutch shaped head,
one horn of which has hinged to it a round bolt extending across and overlapping
the opposite horn. In the opposite horn is fitted a larger bolt having its inside
end formed with a circled "half lap," and its outer end forming a short crank or
lever. The inner top portion of the horn containing, this bolt is cut out to the
extent of the "half lap" in length, and rather wider than the diameter of the
hinged bolt, the loose end of which falls into it when it is horizontal, and the "half
lap" of the larger bolt being turned to the top side of the horn fixes the hinged
bolt firmly, and in this position the hook of the tackle is attached to it, the boat
being securely suspended by its two ends. Along the bottom of the boat close to
the keel is carried in guides a bar attached at each end to one arm of a bell crank,
the other arm of which takes hold of an upright rod, the top end of which is
connected to the short crank or lever before named on outer end of the half
lap bolt in the crutch horn of each of the stanchions. At a point in the bar at
the bottom of boat a heavy weight is arranged to slide easily upon the bar worked
by a hand lever and links so as to strike a blow upon a collar or stop upon the
bar. This blow forces the bar in that direction which moves the bell cranks, and

page_text: blow that instantly acts upon the levers and releases both ends of the boat at the
same moment, and the release can be effected before the boat touches the water if
required, as in the case of the ship going at full speed.
DESCRIPTION OF DRAWINGS.
Figures 1, 2, and 3 illustrate that part of my Invention which relates to improve-
ments in boat davits; Figures 4, 5, 6, 64, and 6B illustrate that part of my Invention
which relates to disengaging gear. Figure 1 shews a side elevation of my improved
davit, with winch gear for working same.
Figure 2 shews a front elevation of same on deck of ship looking seaward.
Figure 3 shews (on a smaller scale) the operation of my improved davits fully
projected on the "weather" side of a ship heeling over, so as to carry the boat clear
of her side, the "lee" side davits being shewn in their upright position.
"
A is the lower part of davit shank supported in a footstep at bottom, and in a
collar at neck; B is the upper part of shank joining the lower part at C above the
rail or bulwark with a hinge joint working on a pin (a), and fixed in position by a
bolt (b); D, D, are stays fixed at E to the davit shank, and at F to a nut working
on a screw G, which is carried in sockets H, H, at its top and bottom ends on side
of ship; J, J, are the side frames of a winch carrying a handle shaft K, on which a
worm pinion L runs loose, except when in gear with a clutch on a spur wheel M,
which slides on keys on the shaft K. When in gear with the clutch of wheel M
the worm pinion L is rotated by the winch handles, and operates a worm wheel N
keyed on the lower part of davit shank, and thus the davits with the boat are
' turned "in board or "outboard," as may be required. When the boat has been
swung "outboard," and it is required to project the davits so as to carry the boat
well clear of the ship the bolt b is knocked out, and the spur wheel M moved out
of gear with the worm pinion. L (which now runs loose), and into gear with an
intermediate spur wheel O, which gears into a spur wheel P on a lower shaft P¹,
which carries also a worm pinion gearing into a worm wheel R keyed on top of
the screw G, which it revolves in the nut F, causing it to travel downward on the
screw, and with it to draw down the stays D, D, and the upper part of davit B
(working on the hinge at C) till it projects at right angles to the ship's side. The
same operation is simultaneously going on with the other davit through the other
winch, or both winches may be worked together by prolonging and connecting the
handle shaft K from one to the other. The boat is now well clear of the ship, and
near to the level of the water ready for disengaging. When the boat is to be
raised the screws are turned the opposite way, and the davits brought back to their
vertical position.
Figure 4 shews a section of one half of a boat having my disengaging gear
fitted.
Figure 5 shews the other half in dotted lines, the boat hanging in the davits, the
winch gear of one of which is shewn in Figure 5. A, B, D, G, and H, shew
respectively the lower and upper shank, stays, screw, and sockets before described;
S and S¹ are the top and bottom blocks of tackle; a, a, are the stanchions at each
end of the boat; b, the crutch shaped heads; f. f. the short arms to which the
rods h, h, are attached; j, j, are bill cranks (fixed to brackets in bottom of boat),
one end of which takes hold of the rod h, and the other of a long bar or rod k
which runs from stem to stern in the bottom of boat. At a certain point in its
length is a collar l, and near to it a weight m slides freely upon the bar or rod K

page_text: worked by a short link bar n attached to a lever handle o, having its fulcrum in a
bracket p (fixed to bottom of boat), and kept in its lowest position by a pin q in
the bracket.
Figures 6, 64, and 6B, shew details of the disengaging gear in the crutch shaped
head B of stanchion A; Figure 6 is a side view shewing the catch open to let the
boat drop.
Figure 6 is a side view shewing the catch closed to hold the boat suspended,
and Figure 6B is an end view of the latter position. A is the stanchion; B, the
crutch head keyed on top; C, the hinged pin working on hinge D in one horn of
crutch E is the half-lap pin working in the boss E¹ of opposite horn of the
crutch, and having the short arm F formed on it, to the end of which the rod h is
attached. The inner side of the boss. E¹ is recessed, as shewn, to allow the
projecting part of the half-lap bolt to revolve, and G is a tongue piece fitted into
the open side after the bolt E is put in, to steady and support the hinged pin C
when the catch is closed and the boat suspended, and keep the bolt E in its place.
The boat being suspended by the tackle hooks taking hold of the hinged bolts C,
which are now firmly held by the half-lap boats (as in Figures 6 and 6B), the men
on board and all ready to let go, the lever handle O is raised into the position.
shewn by dotted lines (Figure 4), and urges the sliding weight m against the
collar, giving a blow which drives the bar or rod k forward, draws down by
means of the bell cranks j, j, the rods h, h, which bring the arms F, F, into the
position shewn in Figure 6, when the hinged pin C flies up, and the boat is
disengaged simultaneously at both ends and falls into the water. When the boat
has to be taken on board again the hinged pins are shut down, the lever handle
brought back to its lowest position, and the bell cranks and rods moved so as to
bring the arms into position shewn in Figure 6A, when the pin C is locked and the
hooks are attached.
Having now described and illustrated my Invention, and the manner in which it
may be carried into practical application, I would state that I do not bind myself
to the details of mechanism for operating the various parts, but what I consider
novel and therefore claim as secured to me by Letters Patent is,―
Firstly. The arrangement of lowering davits actuated by screws revolving in
nuts, to which are attached the stays or struts supporting the lowering portions of
the davits, the said screws being caused to revolve by winch gearing on the deck of
ship, the whole constructed and operating substantially as shewn and described.
Secondly. The arrangement of disengaging gear by which both ends of the boat
are instantly and simultaneously detached by one movement of a handle acting
upon a rod running from end to end of the boat attached to bell cranks, and
through them upon the mechanism in the crutch heads, substantially as shewn
and described..
In witness whereof, I, the said Robert Burdes, have hereunto set my hand
and seal, the Twenty second day of August, in the year of our Lord One
L
Witness,
T. J. DANSON,
Consulting Engineer & Patent Agent,
3, St. Nicholas' Buildings,
Newcastle on Tyne.
ROBERT BURDES. (L.S.)