APPARATUS FOR FACILITATING REPAIRS AND OTHER OPERATIONS UPON A SCREW PROPELLER WHILST THE VESSEL IS AFLOAT
Year: 1880

page_text: LETTERS PATENT to James Bowyer D'Arcy Boulton, of Southampton Row,
in the County of Middlesex, for an Invention of "APPARATUS FOR
FACILITATING REPAIRS AND OTHER OPERATIONS UPON A SCREW PROPELLER
WHILST THE VESSEL IS AFLOAT."
PROVISIONAL SPECIFICATION left by the said James Bowyer D'Arcy
Boulton at the Office of the Commissioners of Patents on the 16th April
1880.
JAMES BOWYER D'ARCY BOULTON, of Southampton Row, in the County of
Middlesex. "APPARATUS FOR FACILITATING REPAIRS AND OTHER OPERATIONS
UPON A SCREW PROPELLER WHILST THE VESSEL IS Afloat."
My Invention relates to apparatus for enabling the blades of what are known
as "built up" screw propellers to be examined, tightened up, removed, repaired,
or exchanged whilst the ship is at sea or elsewhere afloat without raising the
propeller.
My Invention consists of a vertically sliding trunk fitted to move within a fixed
vertical trunk (liko that used to hoist detachable propellers through), which sliding
trunk may be in one or several lengths joined together telescopically or otherwise,
the joints being made watertight by suitable packings. This sliding trunk may
be lowered by screw gear until its bottom ond is nearly on a level with the top
surface of the propeller boss, and this trunk may be guided in its descont by the
edges of the stern frame or other guides. This sliding trunk is provided with an
end or bottom having an orifice fitting on the surface of the boss immediately
surrounding the flange or base of the propeller blade, to which access is desired.
This bottom or end may either be flat or slightly convexed, and when the width
of the blade exceeds the diameter of the flango or base by which it is attached to
the boss the bottom or end of the trunk is constructed or provided with inovable
segments, which may be opened to give passage to such extra width of blade and
closed again.
The modus operandi is as follows:-The propeller having been stopped with
the blade or part of boss to which access is required uppermost, the trunk is
lowered with the movable segments of the bottom opened when necessary to pass
the widest part of the blade, and closed again before the bottom of the trunk is
finally seated upon the boss, the trunk being firmly held down thereon by the
lowering gear. The water is now pumped out, and the desired operations may
then be performed within the trunk.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Bowyer D'Arcy Boulton in the Great Seal Patent Office on
the 16th October 1880.
JAMES BOWYER D'ARCY BOULTON, of Southampton Row, in the County of
Middlesex. "APPARATUS FOR FACILITATING REPAIRS AND OTHER OPERATIONS
UPON A SCREW PROPELLER WHILST THE VESSEL IS AFLOAT."
My Invention relates to apparatus for enabling the blades of what are known
as "built up" screw propellers to be examined, tightened up, removed, repaired,
or exchanged whilst the ship is at sea or elsewhere afloat without raising the
propeller.
My Invention consists of a sliding trunk fitted to move up and down within a
fixed vertical trunk (like that used to hoist detachable propellers through), which
sliding trunk may be in one or several lengths joined together telescopically or
otherwise, the joints being made. watertight by suitable packings. This sliding
trunk may be lowered by suitable gear until its bottom end rests upon the top
surface of the propeller boss, and it may be guided in its descent by the edges of
the stern frame or other guides. This sliding trunk is provided with an end or
bottom having an orifice fitting on the surface of the boss immediately surrounding
the flange or base of the propeller blade, to which access is desired. This bottom
or end may either be flat or slightly convexed, and when the width of the blade
exceeds the diameter of the flange or base by which it is attached to the boss
the bottom or end of the trunk is constructed or provided with inovable segments,
which may be opened to give passage over such extra width of blade.
The modus operandi is as follows:-The propeller having been stopped with
the blade or the part of the boss to which access is required uppermost, the trunk
is lowered with the movable segments of the bottom opened when necessary to
pass the widest part of the blade, the said segments being closed again before the
bottom of the trunk is finally seated upon the boss. The trunk being firmly held
down on its seat on the boss by the lowering gear or other means the water is now
pumped out, and the desired operations may then be performed within the trunk,
which is afterwards raised, the segments being again opened if necessary to allow
it to pass the wide part of the blade. When the trunk is raised to its highest
position the segments are shut, and the central orifice is closed by a cover; the
space within the trunk may then be utilized for stowage of spare gear, such as
warps, fenders, &c., or even spare blades for the propeller.
DESCRIPTION OF DRAWINGS.
Figure 1 is a vertical section of the trunk as hoisted up out of use; Figure 2 is
a similar section of the trunk lowered into position upon the screw to enable the
desired repairs to be effected; Figure 3 is an underside plan on a larger scale of
the trunk bottom showing the hinged segments; Figure 4 is a vertical section of
the trunk bottom as seated on the scrow boss.
A is the fixed vertical trunk or well, which may either be open or be closed at
top by a hatch (not shown) even when in use to prevent entry of water from
above, the men having access through a door way in the side of the fixed trunk.
This trunk A extends down to about the vessel's counter, and terminates with a
narrow internal flange a. B is the sliding trunk baving a similar external flange b
at top, which, when the trunk is lowered, as in Figure 2, interlocks with the
flange to keep out splash. The trunk B may either be in one length, as shown,
or it may be constructed of two or more lengths constructed to slide within one
another, and provided with interlocking flanges, as in the case of the trunks A and

page_text: B, the joints being provided with packings to make them watertight. The sliding
trunk B has snugs b' (Figure 4) rivetted on the outside, and embracing the fore
and aft edges of the stern frame to guide it in its descent. C is the bottom of the
sliding trunk; it is preferably slightly convexed, as shown, but it might be flat.
It has a central opening of circular or other suitable shape large enough to pass
over the flange or base of the propeller blade, the edge c of this opening being
thickened or flanged and bevelled or shaped to correspond to the spherical or other
surface of the boss immediately around the said flange or base, upon which surface
this bevelled edge is to seat itself, as shown in Figures 2 and 4. The edge c may
be grooved to receive a packing of leather or indiarubber, or faced with similar
material to make the joint watertight. This bottom C is constructed with
movable segments D, which are preferably hinged, as at d, to the bottom C, but
might be otherwise connected thereto or even be altogether removable. These
hinged segments may be raised and lowered by means of chains E carried up
through the trunk or by screw or other gear. These segments D form part of the
bottom C, and their lower edge is similarly bevelled and packed to fit closely upon
the propeller boss. The joints between the segments and the rest of the bottom C
are made watertight by being bevelled or by overlapping flanges, as will be readily
understood. These segments D are of such width and length as when lowered to
leave a sufficient opening to allow the bottom of the trunk to pass the widest part
of the blade, should this exceed the diameter of the flange or base of the blade,
but when this is not the case the segments are not required to be movable, and
may remain closed, or the bottom C may be constructed in one piece without
movable segments. When the trunk B is raised, as shown in Figure 1, the
aperture in the bottom may be closed by a loose cover E. The gear for raising
and lowering the trunk B may be a screw shaft F or a pair of such screw shafts at
opposite sides connected by simultaneous gear, as well understood, each screw
turning in a fixed collar fat the upper end, which prevents any longitudinal
motion of the screw, and screwing through a nut G fixed on the inside of the
trunk B, but any other suitable arrangement of raising and lowering gear might
be used.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein before in part recited Letters Patent is,-
1st. The application and employment of a trunk fitted to slide up and down
within a fixed trunk or well, and having an opening at bottom adapted when the
trunk is lowered to fit closely upon the boss of the propeller around the flange or
base of a blade, substantially as and for the purpose shown and described.
2nd. The construction and employment of a trunk fitted to slide up and down
within a well, the bottom of said trunk having an opening, and being provided
with hinged or movable segments adapted to open to pass over the blade and to
close again to fit upon the boss, substantially as and for the purpose specified.
In witness whereof, I, the said James Bowyer d'Arcy Boulton, have here-
unto set my hand and seal, this Thirteenth day of October, in the year of
our Lord One thousand eight hundred and eighty.
JAMES ROWVER DARCY BOULTON (L)