IMPROVEMENTS IN BOAT DISENGAging Gear
Year: 1880

page_text: LETTERS PATENT to John Mackenzie, of Glasgow, in the County of Lanark,
North Britain, Naval Architect, for an Invention of "IMPROVEMENTS IN
BOAT DISENGAging Gear,”
PROVISIONAL SPECIFICATION left by the said John Mackenzie at the Office
of the Commissioners of Patents on the 9th January 1880.
JOHN MACKENZIE, of Glasgow, in the County of Lanark, North Britain, Naval
Architect. "IMPROVEMENTS IN BOAT DISENGAGING GEAR."
This Invention has for its object to improve the construction and action of boat
disengaging gear so as to avoid the defects of the various arrangements hitherto
proposed or in use.
In carrying out the Invention according to one modification the two lower tackle
blocks, by means of which the boat is suspended from the davits, are connected by
a horizontal bar, which may be either an iron rod or tube or a wooden spar fitted
with metal ends. The bar is fitted to the bottoms of the blocks so as to be capablo
of turning about its own axis, and is formed with hooks on its outer ends to receive
the suspensory ring bolts of the boat. A lever is formed or fixed on the bar in any
convenient position, and a holding or catch plate is fitted to the boat so as by
holding the lever in a downward or other certain position to keep the bar in the
position in which its hooks hold up the boat. The boat is disengaged by releasing
the bar lever and with it turning the bar into a position in which the suspensory
ring bolts slip off its hooke. When the boat is hoisted up or taken inboard the
horizontal bar serves for supporting the centre of the tarpaulin or cover.
lower tackle blocks have ordinary hooks jointed to them, either or both of which
may be used for connecting the boat to the tackle when about to hoist the boat out
the water.
The
In a second modification sliding bolts are fitted on the horizontal bar to engage
with the suspensory ring bolts of the boat, each ring entering up into a forked
piece which is fixed to the tackle block, and across which the bolt passes. The two
bolts are connected to a hand lever upon the bar, and are drawn by moving this
lever, the boat being thereby disengaged.

page_text: In other modifications the horizontal bar with its turning arrangement, or the
sliding bolts, are fitted to the boat and engage with rings or links attached to the
lower tackle block.
Any of the modifications may be made automatic by having a rope of a suitable
length, with one end fixed to the davit or ship's side, and the other to the turning
or disengaging lever. When the boat is lowered sufficiently to tighten the rope it
causes the lever or bar to turn and effect the disengagement of the boat. When the
turning bar attached to the lower tackle blocks is used it may have a weighted
lever fixed to it in a position to turn the bar and invert the holding hooks whenever
the boat reaches the water, and the strain of its weight is thereby taken off the
hooks. In this case the hooks must of course be shaped so that the strain on them
of the boat's weight will keep the bar in the holding position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Mackenzie in the Great Seal Patent Office on the 6th July
1880.
JOHN MACKENZIE, of Glasgow, in the County of Lanark, North Britain, Naval
Architect. "IMPROVEMENTS IN BOAT DISENGAGING GEAR.”
My said Invention has for its object to improve the construction and action of
boat disengaging gear so as to avoid the defects of the various arrangements hitherto
proposed or in use.
In carrying out my Invention according to one modification the two lower tackle
blocks, by means of which the boat is suspended from the davits, are connected
by a horizontal bar which can turn about its own axis, and has hooks at its ends
to receive the suspensory ring bolts or other connections of the boat. The bar is
retained in the position in which its hooks hold up the boat by a lever fastened in
any convenient way, or by means of an angular frame placed to support the middle
of the bar, and which is turned down or removed when the boat is to be disengaged,
the disengagement being effected by turning the bar by means of the lever or
otherwise so as to invert its hooks. When the boat has been hoisted up or taken
inboard the horizontal bar serves as a ridge pole for supporting the centre of the
tarpaulin or cover. The bar also serves to prevent the blocks and tackle from
becoming disarranged or twisted. The lower tackle blocks may have ordinary
hooks jointed to them in addition to the bar hooks, either or both of which may
be used for connecting the boat to the tackle when about to hoist the boat out of
the water.
In a second modification sliding bolts are fitted to the horizontal bar to engage
with the suspensory ring bolts or other connections of the boat; or jointed bolts
or catches may be used which will release the boat on the bar being turned.
In other modifications the horizontal bar with its turning or other disengaging
arrangement is fitted to the boat, and engages with rings, links, or hooks attached
to the lower tackle blocks.
Any of the modifications may be made automatic by having a rope of a suitable
length, with one end fixed to the davit or the ship's side, and the other to the
turning or disengaging lever. When the boat is lowered sufficiently to tighten the
rope it causes the lever or bar to turn and effect the disengagement of the boat.
When the turning bar attached to the lower tackle blocks is used it may have a
weighted lever fixed to it in a position to turn the bar and invert the holding
hooks whenever the boat reaches the water, and the strain of its weight is thereby
taken off the hooks. In this case the hooks must of course be shaped so that the
strain on them of the boat's weight will keep the bar in the holding position.
And in order that my said Invention and the manner of performing the same
may be properly understood, I hereunto append three Sheets of explanatory
Drawings, to be hereinafter referred to, and representing various modifications of
my improved boat disengaging gear. In these Drawings the same reference
numerals are used to mark the same or like parts wherever they are repeated.
Figures 1 and 2 on Sheet 1 of the Drawings are a longitudinal vertical section
and a sectional end elevation showing one modification of my improved disengaging
gear. The two lower tackle blocks 21, by means of which the boat is suspended
from the davits 22, are connected by a horizontal bar 23, which may be either an
iron rod or tube, or, as shown in Figures 1 and 2, a wooden spar fitted with metal
ends;
the bar 23 is fitted to the bottoms of the straps or frames of the tackle
blocks 22 in the manner indicated in the enlarged sections, Figures 9, 10, Sheet 2,
or in any other convenient way, but so as to be capable of turning about its own
longitudinal axis, and is formed with hooks 24 on its outer ends to receive the
suspensory links or rings 25 attached to the boat. A short lever 26 is formed or

page_text: fixed on the bar 23, and may be secured by a light cord 27 to a thwart or other
convenient part of the boat, for the purpose of holding the bar 23 with its hooks 24
directed upwards in the position for holding up the boat. When the boat is to be
disengaged the cord 27 is unfastened or cut and the bar 23 is turned so as to invert
the hooks 24, this action setting the boat free at both ends simultaneously. When
the boat has been hoisted up or taken inboard .the middle part of the bar 23 is
supported by a frame 28 consisting of an upright with inclined side pieces, and the
bar 23 then serves as a ridge pole for supporting the tarpaulin or cover.
Figure 3 is a longitudinal vertical section showing a second modification, Figure 4
being an end view of one of the lower tackle blocks 21 and parts connected to it.
In this modification the horizontal bar 23 may be rigidly fixed to the straps or
frames of the tackle blocks 21. To the bottoms of these blocks or to the ends of
the bar forked or jaw pieces 29 are fixed, the sides or prongs being perforated to
allow of the passage across of the bolts or rods 30. The rings or links 25 are
entered up between the jaws 29, and the rods or bolts 30 are then passed across
through them. The rods 30 are connected to opposite ends of a double lever 31
which can by means of a handle 32 be turned to move them inwards or outwards
simultaneously. When the rods or bolts 30 are drawn inwards the rings or links 25
are set free and the boat is disengaged.
Figures 5 and 6 on Sheet 2 of the Drawings are longitudinal and transverse
vertical sections of a modification in which a horizontal bar 33 corresponding in
some respects to the bar (23) connecting the lower tackle blocks 21 in other
modifications is fitted to the boat, being by preference placed, as shown, at the
bottom of the boat although it might if desired be placed at a higher level. This
bar 33 is formed with hooks 24 which are directed downwards when in the holding
position, and which engage with links, rings, or hooks 25 of chains connected to the
tackle blocks 21. The bar 33 is retained in the holding position by means of a
lever 26 and cord 27.
Figure 7 on Sheet 2 of the Drawings is a longitudinal vertical section of a modifi-
cation like that shown in Figures 1 and 2, and herein before described, excepting
that the bar 23 is shown as an iron rod, and instead of having hooks (24) formed
on its oxtreme ends is formed with a lateral hook or projection 34 to the inner
side of cach tackle block 21.
Figures 11 and 12 on Sheet 3 are a longitudinal vertical section and a sectional
end elevation of a modification like that shown in Figures 1 and 2, and hereinbefore
described, except that it is modified so as to act automatically, or so that the boat
becomes disengaged on reaching the water and being sufficiently supported thereby.
The horizontal bar or ridge pole 23 has its ends fitted to it so that it is a little to
one side of the centres about which the ends or hooks 24 turn, whilst the bearing
surfaces of the hooks 24 and the tops of the suspensory links or rings 25 are made
nearly flat, as shown on an enlarged scale in Figure 15. With this construction,
when the weight of the boat is sustained by the hooks 24, the bar 23 retains its
holding position, but when the bont is water-borne and the strain on the hooks 24
is relieved the bar 23 turns round and inverts the hooks. An ordinary link or
ring 25 may be used instead of the one shown in Figures 12 and 15 if the hook 24
is made as shown in Figure 16, that is, with its bearing part a little below the
axis about which it turns. Instead of constructing the parts with the bar 23 a
little to one side of the axis about which the hooks turn the bar may have a
weight or weighted lever applied to one side of it.
If in the modification shown in Figures 1 and 2, and hereinbefore described, the
hooks 24 are made a little eccentrically, or with their bearing parts a little to one
side, it will be unnecessary to apply force to turn the bar 23 for the purpose of
letting go, as on unfastening or cutting the cord 27 the weight of the boat acting
on the eccentric hooks will cause the bar to turn so as to invert the hooks.
When a horizontal bar 33 is fitted to the boat, as in the modification shown in
Figures 5 and 6, modifications of the hooks 24, similar to what have been described

page_text: for the upper bar 23, may be employed, and are shown in Figures 17, 18, and 19,
on Sheet 3.
Figure 13 on Sheet 3 is a longitudinal vertical section, and Figure 14 is an
enlarged sectional end view showing another modification, in which the turning of
the horizontal bar 23, forming the principle feature of my improved apparatus, may
be made to disengage the boat. In this modification each lower tackle block 21
has attached to it a forked bracket 35, in one part of which the metal end 36 of
the bar 23 has a bearing admitting of the turning of the bar, whilst a tongue or
catch 37 is jointed to the other part. The extreme end of the metal fitting 36 is
of a horse-shoe section, as best seen in Figure 14, and when it is turned with the
open part downwards the tongue 37 can be turned up into it, with the suspensory
link or ring 25 on it, and then if the bar 23 is turned half round the tongue and link
will be securely held, being released when required by turning the bar back again.
Having thus particularly described my said Invention and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel and
original, and claim as the Invention secured to me by and in terms of the herein-
before in part recited Letters Patent is,-
1. The combination with the lower tackle blocks of the bar connecting those
blocks, and formed or fitted with hooks or catches for engaging with the suspensory
connections of the boat, and disengaging therefrom by the turning of the bar,
substantially as herein before described.
2. The combination with the lower tackle blocks of a bar connecting those
blocks and serving as a ridge pole or support for the tarpaulin or cover of the boat
when the latter is hoisted or inboard, substantially as hereinbefore described.
3. The combination with the lower tackle blocks of a bar fitted with rods or
bolts at opposite ends for simultaneously engaging with or disengaging the
suspensory connections of the boat by means of a single hand lever, substantially
as hereinbefore described with reference to Figures 3 and 4- of the accompanying
Drawings.
4. The fitting of the boat with a horizontal bar (33) having hooks at the ends
for simultaneously engaging with or disengaging the suspensory connections, the
parts being arranged and operating substantially as hereinbefore described with
reference to Figures 5, 6, 17, 18, 19 of the accompanying Drawings.
In witness whereof, I, the said John Mackenzie, have hereunto set my hand
and seal, this Third day of July, in the year of our Lord One thousand
cight hundred and eighty.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JOHN MACKENZIE. (L.S.)