Improvements in Apparatus for Raising and Lowering Ships' Boats.
Year: 1888

page_text: Improvements in Apparatus for Raising and Lowering Ships' Boats.
I, FERDINAND ARNOLD LUDWIG DE GRUYTER of Nos. 27 and 38 Leidoche Straat
Amsterdam, in the Kingdom of Holland, Merchant do hereby declare the nature of'
this invention to be as follows:-
This invention has reference to apparatus for raising and lowering ships boats, the
object being to enable a ships boat, even when equipped and manned, to be raised
clear of the chocks with facility.
For this purpose a screw arrangement is employed between the davits and the boa
as will now proceed to explain.
At the upper extremities the davits are bifurcated and each prong is recessed to
receive trunnions projecting from a block that is formed like a nut with a hole with
female screw thread to receive a male screw that is provided with a handle or lever
by which can be turned.
The upper block of the boat lowering tackle is connected by a swivel joint to the
screw which is provided with a head by which the said tackle is supported. With
this arrangement by turning the handle or lever and consequently the screw a boat
suspended to the tackle will be raised or lowered according to the direction which
the screw is turned. Assuming a loaded boat to be on the chocks, if the two
screws be turned simultaneously the boat can be raised from the chocks then it can
he worked out and lowered over the ships side in the ordinary way.
a
Instead of applying the screw between the davit and the upper tackle block,
right and left banded screw may be applied between the boat and the lower tackle
block. In this case it is not necessary to form the upper extremities of the davits as
hereinabove described, the right and left handed screw passes through two nuts or
blocks formed with female screw threads the upper one being connected by plates,
link or stirrup to the frame of the lower tackle block and the lower one being

page_text: similarly connected to the boat or to a hook or ring carried by it. The right and
left-handed screw is provided with a handle or lever by turning which the lower
nut can be caused to approach or recede from the upper one to raise or lower
the boat.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.
I, FERDINAND ARNOLD LUDWIG DE GRUYTER of Nos. 27 and 38 Leidsche Straat,
Amsterdam, in the Kingdom of Holland, Merchant, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:—
This invention has reference to apparatus for raising and lowering ships' boats,
the object being to enable a ship's boat, even when equipped and manned, to be easily
raised clear of the chocks or lowered on to them.
For this purpose a screw arrangement is employed between the davits and the boat
as I will now proceed to explain.
At the upper extremities the davits are bifurcated and each prong is recessed to
receive trunnions projecting from a block that is formed like a nut with a hole with
female screw thread to receive a male screw that is provided with a handle or lever
by which it can be turned.
The upper or standing block of the boat lowering tackle is connected by a swivel
joint to the screw which is provided with a head by which the said tackle is
supported.
In order that the nature of my invention may be readily understood reference is
had to the accompanying sheet of illustrative drawings in which Fig. 1 is an elevation
of part of a davit, with boat raising and lowering apparatus according to this
invention suspended therefrom.
Figs. 2 and 3 are respectively an elevation at right angles to Fig. 1 and a plan or
top view, of the davit and upper part of the apparatus.
Fig. 4 illustrates in elevation a modification hereinafter described.
1 is part of a davit, bifurcated at its upper end; the prongs 2 thereby formed are
each recessed as shown to form a bearing 3. 4 is a block formed with an internal

page_text: screw thread to serve as a nut for a screw threaded rod 5; the said block is formed
with trunnions 6 which are journaled in the bearings 3 in such a manner that they
may turn therein and permit the rol 5 to readily adjust itself to the strain thereon.
The screw threaded rod 5 which is provided with a hand lever 7, is connected by a
swivel joint 8 to the top of the upper block 9 of lowering tackle that may be of
ordinary kind and which comprises a pair of pulley blocks as shewn.
With this arrangement by turning the hand lever 7 and consequently the screw
threaded rod 5, a boat suspended to the lower or running" block will be raised or
lowered according to the direction in which the screw is turned. Assuming a loaded
boat to be on the chocks and each of two davits to be fitted with apparatus of the
kind hereinbefore described if the two screws be turned simultaneously the boat can
be raised from the chocks, then it can be worked out and lowered over the ship's side
in the ordinary way, the nuts 4 turning when necessary in their bearings on the
davits and permitting the screw threaded rods to adjust themselves in line with
the pull of the lowering tackle and thereby preventing lateral strain on the rods.
Instead of applying the screws between the davit and the upper tackle block in the
manner shewn in Figs. 1 to 3 a right and left handed screw 5, 5* may be applied
between the boat and the lower tackle block as shewn in elevation in Fig. 4. In this
case it is not necessary to form the upper extremities of the davit as hereinbefore
described and shewn in Figs. 1 to 3. The right and left handed screw 5, 5* passes
through two nuts or blocks 4, 4* formed with female screw threads, the upper one
being connected by plates, link or stirrup 10 to the frame of the lower tackle block
and the lower one being similarly connected to the boat or to a hook or ring carried
by it. The right and left handed screw is provided with a hand lever as before by
turning which the lower nut can be caused to approach or recede from the upper one
to raise or lower the boat.
When the apparatus is not in use the land lever (or levers) may be locked in
position in any convenient manner, it may be by a hook and chain connected with
one of the davits as indicated in Fig. 2.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. In apparatus for raising and lowering ships' boats the combination with a tackle
block of a screw and nut so mounted and arranged that they can move in relation to
the davit to enable the screw to conform to the direction of the strain upon it
substantially as described.
2. The improved apparatus for raising and lowering ships' boats constructed and
operating substantially as herein described and illustrated in Figs. 1, 2 and 3 of the
drawings annexed.
3. The modified form of apparatus for raising and lowering ships' boats con-
structed and operating substantially as herein described and illustrated in Fig. 4 of
the drawings annexed.
Babad Al.. 118k dan Wah-M 1900
1900
F. A. L. DE GRUYTER.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.