IM- PROVEMENTS IN REMOVING AND REPLACING THE BLADES OF SCREW PROPELLERS OF SHIPS AND OTHER NAVIGABLE VESSELS WHILE AFLOAT, AND IN APPARATUS
Year: 1874

page_text: LETTERS PATENT to John Pinker and Thomas Alfred Adamson, both
of Liverpool, in the County of Lancaster, for the Invention of "IM-
PROVEMENTS IN REMOVING AND REPLACING THE BLADES OF SCREW PROPELLERS
OF SHIPS AND OTHER NAVIGABLE VESSELS WHILE AFLOAT, AND IN APPARATUS
Sealed the 11th December 1874, and dated the 7th September 1874.
PROVISIONAL SPECIFICATION left by the said John Pinker and
Thomas Alfred Adamson at the Office of the Commissioners of
Patents, with their Petition, on the 7th September 1874.
WC, JOHN PINKER and THOMAS ALFRED ADAMSON, both of Liverpool,
in the County of Lancaster, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN REMOVING AND REPLACING THE BLADES OF
SCREW PROPELLERS OF SHIPS AND OTHER NAVIGABLE VESSELS WHILE AFLOAT, AND
IN APPARATUS EMPLOYED THEREFOR," to be as follows:-
-
Our Invention relates to removing and replacing the blades of screw
propellers of steam ships while afloat, and when such blades aro made
detachable from the bosses of the propellers.

page_text: At present in removing and replacing the blades it is necessary to put
the vessel in a dry dock, or to use other like means of exposing the
propeller as far as the boss, so that workmen can get at it; but in many
instances dry docks cannot be had; also other means of exposing the
propeller boss, and such processes are always attendant with considerable
cost and delay. In some instances caissons have been used round the
propeller, and the water then pumped out; but this is likewise a costly
and difficult process.
Our Invention consists in removing the detacheable blades of screw
propellers through an adjustable trunk or pipe, which is so constructed
as to encircle the blade required to be removed, and of such dimensions
as to allow of a workman operating within it, or so arranged that the
workman can operate by means of suitable spanners from the ships'
deck.
In carrying out this Invention into practice the bosses of screw
propellers are provided round the root of each blade with a provision
having a screw thread, which may be on the boss itself, or on a ring, by
preference of brass, shrunk on and attached to the boss. One of the
couplings of the propeller shaft is fitted with a provision, being a bolt,
stud, or other suitable means for locking and adjusting the propeller
boss in position required for operation, that is, bringing the screwed
provision on the boss with its centre quite true with the stern post of the
vessel, or at a suitable angle thereto. We form the connecting piece of
the stern post forging, that is, the upper part connecting the stern post
with the rudder post of screw ships in the form of a hoop; and we build
in the stern of the vessel and immediately above this hoop or ring a
well, which opens out through the deck above. This well is arranged
on a true centre witli the before-mentioned screwed provisions on the
boss of the propeller as they respectively may be uppermost.
An apparatus for removing the detachcable blades of screw propellers
consists of a trunk or pipe of size suitable to pass down the well before
mentioned in the stern of the ship, and of length sufficient to reach to
the screwed provisions on the propeller boss. The bottom of the trunk
or pipe is formed with a female screwed provision, so as to take or screw
on to the uppermost screwed provision on the propeller boss, the blade
to be operated upon thus coming inside the trunk or pipe. The trunk or
pipe being in position the water is pumped out and workmen can get
at the bolts attaching the propeller blades to the boss in the case of large

page_text: vessels direct, and in the case of smaller vessels by box spanners from
above. It will thus be seen that by the use of this Invention detacheable
blades of screw propellers can be removed while a vessel is afloat or at
sea; and when propeller blades are broken new ones can be substituted,
or any other repairs or alterations effected that may be necessary.
In the case of old vessels, or vessels where it is difficult and un-
desirable to build the well directly in the centre of the stern of the ship,
the well can be built at an angle, the locking arrangement in connection
with the screw shaft being adjusted to suit; or an independent trunk
may be employed without passing through the counter of the vessel or
in connection therewith.
In practice the trunk or pipe used in carrying out this Invention may
be made of any material, but we prefer steel for lightness. The trunk
may be made in one or more lengths, and may be in some instances
made telescopic in the well at the stern of the vessel, and so that it will
draw down when required for use. It may be turned to screw on to the
screwed provision on the boss by a cross spanner, handspikes, or other
suitable means. The bottom may be fitted with a guide or a taper
screw so as to more readily adjust it to the screwed provision on the
boss. Spare screw blades and requisite tools may be carried with the
ship.
SPECIFICATION in pursuance of the conditions of the Letters' Patent,
filed by the said John Pinker and Thomas Alfred Adamson in the
Great Scal Patent Office on the 5th March 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wc, JOHN
PINKER and THOMAS ALFRED ADAMSON, both of Liverpool, in the
County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-eighth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto us, the said John Pinker and Thomas
Alfred Adamson, Her special licence that we, the said John Pinker and
Thomas Alfred Adamson, our executors, administrators, and assigns,,
or such others as we, the said John Pinker and Thomas Alfred
•

page_text: Adamson, our executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN REMOVING AND REPLACING THE BLADES OF SCREW
PROPELLERS OF SHIPS AND OTHER NAVIGABLE VESSELS WHILE AFLOAT, AND IN
APPARATUS EMPLOYED THEREFOR," upon the condition (amongst others) that
we, the said John Pinker and Thomas Alfred Adamson, our executors
or administrators, by an instrument in writing under our. or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that we, the said John Pinker and Thomas Alfred
Adamson, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
Our Invention relates to removing and replacing the blades of screw
.propellers of steam ships while afloat, and when such blades are made.
detacheable from the bosses of the propellers.
At present in removing and replacing the blades it is necessary to put
the vessel in a dry dock, or to use other like means of exposing the
propeller as far as the boss, so that workmen can get at it, but in many
instances dry docks cannot be had; also other means of exposing the
propeller boss, and such processes are always attendant with considerable
cost and delay. In some instances caissons have been used round the
propeller, and the water then pumped out; but this is likewise a costly
and difficult process.
Our Invention consists in removing the detacheable blades of screw
propellers through an adjustable trunk or pipe, which is so constructed
as to encircle the blade required to be removed, and of such dimensions
as to allow of a workman operating within it, or so arranged that the
workman can operate by means of suitable spanners from the ships'
deck.

page_text: In carrying out this Invention into practice the bosses of screw
propellers are provided round the root of each blade with a provision
having a screw thread, which may be on the boss itself, or on a ring, by
preference of brass, shrunk on and attached to the boss. One of the
couplings of the propeller shaft is fitted with a provision, being a bolt,
stud, or other suitable micans for locking and adjusting the propeller boss
in position required for operation, that is, bringing the screwed provision
on the boss with its centre quite true with the stern post of the vessel,
or at a suitable angle thereto. We form the connecting piece of tho
stern post forging, that is, the upper part connecting the stern post
with the rudder post of screw ships in the form of a hoop; and we build
in the stern of the vessel and immediately above this hoop or ring a
well, which opens out through the deck above. This well is arranged
on a true centre with the before-mentioned screwed provisions on the
boss of the propeller as they respectively may be uppermost.
An apparatus for removing the detachable blades of screw propellers
consists of a trunk or pipe of size suitable to pass down the well before
mentioned in the stern of the ship, and of length sufficient to reach to
the screwed provisions on the propeller boss. The bottom of the trunk or
pipe is formed with a female screwed provision, so as to take or screw on
to the uppermost screwed provision on the propeller boss, the blade to be
operated upon thus coming inside the trunk or pipe. The trunk or pipe
being in position the water is pumped out, and workmen can get at the
bolts attaching the propeller blades to the boss in the case of large vessels
direct, and in the case of smaller vessels by box spanners from above.
It will thus be seen that by the use of this Invention detacheable blades
of screw propellers can be removed while a vessel is afloat or at sea; and
when propeller blades are broken new ones can be substituted, or any
other repairs or alterations effected that may be necessary.
In the case of old vessels, or vessels where it is difficult and un-
desirable to build the well directly in the centre of the stern of the ship
the well can be built at an angle, the locking arrangement in connection.
with the screw shaft being adjusted to suit. Or an independent trunk
may be employed without passing through the counter of the vessel or
in connection therewith.
In practice the trunk or pipe used in carrying out this Invention may
be made of any material, but we prefer steel or iron for lightness. The
trunk may be made in one or more lengths; and may be in some

page_text: '
instances made telescopic in the well at the stern of the vessel, and so
that it will draw down when required for use. It may be turned to
screw on to the screwed provision on the boss by a cross spanner, hand-
spikes, or other means. The bottom may be fitted with a guide or a
taper screw, so as to more readily adjust it to the screwed provision on
the boss. Spare screw blades and requisite tools may be carried with
the ship.
The before-going being the nature, object, and purposes of this our
Invention we will now proceed to describe how the same may be carried
into practical effect, and for that purpose we have hereunto attached a
Sheet of Drawings marked with letters and figures of reference corre-
sponding with those in the following explanation :-
Figure 1 is a sectional elevation of a portion of the after end of a
screw steam ship fitted with apparatus according to our Invention for
removing and replacing propeller blades; Figure 2 is a plan of Figure 1;
Figure 3 is an end elevation of Figure 1.
Figure 4 is an end elevation, showing modification of our Invention.
Figure 5 is a sectional elevation of the after end of a screw steam
ship fitted with apparatus according to our Invention for removing and
replacing propeller blades, the apparatus in this case being shown raised
and out of gear.
Figures 6, 7, 8, and 9, show apparatus constructed according to our.
Invention, and methods of attaching same to the propeller boss.
Upon reference to the Drawings it will be seen that A is a screw
aperture of a screw steamer; B, propeller; C, boss of propeller; D,
stern post; E, rudder post; F, screw shaft; G, screw shaft couplings;
His an adjustable trunk or pipe which is so constructed as to encircle
the blade of the propeller B. The boss C of the proppeller B has round
the root of each blade a provision so arranged that the trunk H will
rest or screw thereon; Figures 6, 8, and 9, represent several methods
by which a joint may be effected between the trunk H and the boss C;
Figure 6 represents the trunk fitting on the boss, the joint being made
with any suitable packing; Figure 8 represents the trunk H with an
india-rubber packing ring K.; Figure 9 represents the trunk Harranged
to screw on to propeller boss C; L is the forging connecting the stern
post D to the rudder post E, which is formed in the shape of a hoop,

page_text: as shown at Figure 2. In the stern of the vessel and immediately above
this hoop L we build a well M, which opens out to the deck above.
This well is arranged so that the trunk H may pass therethrough over
the blade of the propeller B.
In some cases the trunk H may be made telescopic to stow in the
well M.
In the case of old vessels we build the well at an angle or at the
side of the forging connecting the stern and rudder posts, as shown at
Figure 4.
One of the couplings G of the propeller shaft F may be fitted with
any suitable locking gear for locking the propeller in correct position to
receive the trunk H, as will be understood. In operation the damaged
blade of the propeller B is brought into position, the trunk H is then
shipped over the blade and the trunk pumped out; thus allowing work-
men to get at the propeller blade, either direct or by means of spanners,
as will be understood.
Having now fully described our Invention, and shown how the same
may be carried into practical effect, we would have it understood that
we do not confine ourselves to any particular size or detail of apparatus,
as shown, as the same may be considerably varied without departing
from our Invention; but what we claim as our Invention and secured
to us by Letters Patent as aforesaid is, the method of and apparatus for
gaining access to, removing, and replacing the blades of screw propellers
of ships and navigable vessels while afloat, substantially in the manner
and for the purposes set forth and shown in the before-going Specifi-
cation and accompanying Drawings.
In witness whereof, we, the said John Pinker and Thomas Alfred
Adamson have hereunto set our hands and seals, this Second
day of March, in the year of our Lord One thousand cight
JOHN (L.S.) PINKER.
THOMAS ALFRED (L.S.) ADAMSON.