Year: 1897

page_text: A communication from JOHN WILLIAM GLAHOLM, of Nanaimo, British Columbia,
of the Dominion of Canada, Wharfinger.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:
This invention relates to screw steamers, its object being the construction of
apparatus to enable a propeller to be inspected or repaired without altering the
trim of the vessel or dry-docking her, so that if necessary a damaged propeller may
be repaired or replaced by another while the vessel is at sea.
According to this invention the stern of the ship is provided with chambers
adapted to be lowered so as to enclose the propeller and make a sufficiently tight
joint with the hull and stern-frame to enable the water to be pumped out after the
chambers are in position, so that access to the propeller or outboard end of the
stern tube can readily be obtained through the tops of the chambers.
Conveniently the stern of the ship may be provided with cavities in which these
chambers when not required for service can be housed in a position in which they
are always ready for use.
For example the stern of the ship may be fitted with casings arranged to slide
vertically through the skin plating downward and upward along the deadwood
and rudder post which if desired may be channelled or provided with guides to
receive them; conveniently the lower ends of the casing may be provided with
doors so constructed that when the casings have been lowered down so as to have
the propeller between them the doors may be raised from the deck to close the
openings which would otherwise exist at the bottoms of the casings.
For operating these doors chains may be led to the deck from the doors over
suitable guide pulleys, or screw and worm gear may be employed for closing the
doors and for raising and lowering the casings.
The foregoing construction is described by way of example but other arrange-
ments can be employed without departure from this invention; for instance the
casings might be arranged to swing into place laterally from each side of the
propeller, being guided by rocking arms or linkages.
In vessels having more than one propeller the form of the casing can be altered to
suit the position of the propeller and the form of the portion of the stern tube or
skin plating upon which it will have to fit.
Dated this 27th day of July 1807
BOULT & WADE,
Agents for the Applicant.

page_text: A communication from Joux WILLIAM GLAHOLM, of Nanaimo, British Columbia,
of the Dominion of Canada, Wharfinger.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to screw steamers, its object being the construction of
apparatus to enable a propeller to be inserted or repaired without altering the
trim of the vessel or dry-docking her, so that if necessary a damaged propeller may
be repaired or replaced by another while the vessel is at sea.
According to this invention the stern of the ship is provided with chambers
adapted to be lowered so as to enclose the propeller and make a sufficiently tight
joint with the hull and stern-frame to enable the water to be pumped out after the
chambers are in position, so that access to the propeller or outboard end of the
stern tube can readily be obtained through the tops of the chambers.
Conveniently the stern of the ship may be provided with cavities in which these
chambers when not required for service can be housed in a position in which they
are always ready for use.
For example the stern of the ship may be fitted with casings arranged to slide
vertically through the skin plating downward and upward along the deadwood
and rudder post which if desired may be channelled or provided with guides to
receive them; conveniently the lower ends of the casing may be provided with
doors so constructed that when the casings have been lowered down so as to have
the propeller between them the doors may be raised from the deck to close the
openings which would otherwise exist at the bottoms of the casings.
For operating these doors chains may be led to the deck from the doors over
suitable guide pulleys, or screw and worm or other gear may be employed for
closing the doors and for raising and lowering the casings.
The foregoing construction is described by way of example but other arrange
ments can be employed without departure from this invention; for instance the
casings might be arranged to swing into place laterally from each side of the
propeller, being guided by rocking arms or linkages.
In vessels having more than one propeller the form of the casing can be altered to
suit the position of the propeller and the form of the portion of the stern tube or
skin plating upon which it will have to fit.
In the accompanying drawings,
Fig. 1 is a perspective view of the stern of a steamer with a pair of casings
according to this invention adjusted to surround the propeller and extending
above the load water-line so that when the water within the casings is removed
the propeller is accessible.
Fig. 2 is a sectional plan on the plane of the load water-line showing the guide
in which the casings slide vertically and one arrangement of the packing by which
a tight joint between the casings and the skin plating is established;
Fig. 3 is a side elevation of the stern shown in Fig. 1, with the casings drawn up
or " housed."
Fig. 4 is an elevation of the stern of a twin-screw steamer with casings according
to this invention pivotted thereto for adjustment in the manner hereinafter
described.
Like letters indicate like parts throughout the drawings.

page_text: With reference first to Figs. 1, 2 and 3, casings A A¹ are arranged to slide
vertically through openings B which extend through the stern and open at their
upper and lower ends upon the deck and the skin-plating respectively; the
flanged edges A2 of the casings are maintained in engagement with the hull H
(in the manner indicated in Fig. 2) by Z-irons B¹ rivetted to the latter.
The lower end of each casing is provided with a door A³ controlled by chains A
which pass to the deck over guide-pulleys A. By these chains the doors are
allowed to fall open whilst the casings A A¹ are being lowered past the propeller C;
the doors are pulled up to close the lower ends of the casings as soon as the latter
have been lowered to the full extent of their travel. D is a pneumatic tube
secured to each casing and door and adapted to form, when inflated after the casing
has been lowered as described, a packing for the joints between the doors A3 and
the casings and between the casings and the contiguous faces of the skin plating.
The pressure of the water outside the casings tends to keep the doors A³ shut
and all the aforesaid joints tight when the interiors of the casings are pumped
dry; the packing employed is not of necessity pneumatic. Further, packing may
be dispensed with altogether provided that the fitting of the parts is so accurate
as not to permit more leakage into the casings than can readily be kept under by
a pump.
Any convenient means may be adopted for raising and lowering the
casings A A' in the example illustrated by Fig. 3 each casing is raised by a
chain A passing over a block E at the end of a derrick E¹ to one of the ships
winches; there are two such chains, one to each casing, although to avoid con-
fusion only one is shown in Fig. 3.
The height to which the casings A A¹ extend above load water-line may be such
that their upper edges never descend clear of the hull, or may be so much less
as to permit access to the interior of the casings over their tops from a boat
alongside.
In the example illustrated by Fig. 4 each casing is carried on the end of an
arm F pivotted to a bracket Ġ secured to the hull. Each arm is rotatable by
means of a worm wheel F' secured thereto, which is turned by the worm J. An
opening K is made in the forward part of each of the casings to allow them to pass
over the stern tube and propeller shaft, these openings being afterwards covered
by doors A controlled by chains A and so disposed outside the casing that like
the doors A3 in Figs. 1, 2 and 3 they tend to make a tight joint with the casing
under the influence of the external head of water. When the interior of the
casing is emptied the arms F can be turned upward and inboard and may then
have the casings A A¹ detached from them.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner
the same is to be performed I declare that what I claim is:--
1. In a screw-steamer the use of one or more casings mounted thereon and
adjustable to enclose the propeller.
2. In a screw steamer the combination with the hull of an adjustable casing
mounted to slide therein and provided with a bottom door substantially as and for
the purpose described.
3. In a screw steamer the combination with the hull of a casing such as A
pivotted thereto and provided with an opening such as K and door such as A7
substantially as described or illustrated in the accompanying drawings.
4. In a screw steamer the combination with the hull of one or more casings
mounted thereon adjustable to enclose the propeller and provided with pneumatic
packing.
5. In a screw steamer the combination with the hull of one or more casings
mounted thereon and housed therein substantially as described.
6. In a screw steamer the combination with the hull of one or more casings

page_text: arranged and operating substantially as described and illustrated in Figures 1, 2
and 3 or in Figure 4 of the accompanying drawings.
D
་
075
1 1000
BOULT & WADE,
Agents for the Applicant.