Improved Centre-board or Drop-keel Apparatus for Yachts and the like.
Year: 1894

page_text: Date of Application, 29th Jan., 1894
Complete Specification Left, 27th Oct., 1894-Accepted, 1st Dec., 1894
PROVISIONAL SPECIFICATION.
Improved Centre-board or Drop-keel Apparatus for Yachts and
the like.
I, FRANCIS WENTWORTH BREWSTER of Chesterfield House, West Cliff
Gardens, Bournemouth, Gentleman, do hereby declare the nature of the said
invention to be as follows:-
This invention relates to the application to centre-boards or drop-keels (herein-
after referred to as centre boards) of yachts and other marine vessels using such
appliances, of adjustable means of ballasting the same, either in such a manuer that
the ballast may automatically shift to its lowest and most useful position, whether
the centre-board be up or down, or so that such means may be mechanically or
otherwise equivalently shifted to such position or otherwise as may be required.
Said adjustable ballast may consist of rolling weights, or of sliding weights, or
of gun shot, or of various other means preferably of greater specific gravity than
water, and may be applied to the centre-board in various ways so as to be
automatically operative in manner aforesaid upon the centre board being raised or
lowered, or so as to be capable of being mechanically shifted, as may be required,
so that they may be under entire control.
According to one modification of carrying the invention into effect, the centre-
board is made or fitted with a continuous angularly disposed hollow casing 80
disposed that about one half of its length assumes a horizontal position when the
centre-board is up, and the remaining part of its length assumes such a position
when the centre-board is down. Within such continuous angularly disposed hollow
casing is fitted a series of independent sliding or rolling weights which automatically
shift their position within and gravitate to the lowest part of the casing according
to the position of the centre board.
The ballast weights may be oblong and fitted with lateral bearings engaging with,
so as to slide between or on, inner projecting parts of the casing, or they may be
circular and fitted with lateral trunnions engaging with so as to roll between or on
such guiding parts of the casing, or they may simply slide or roll between the
walls of the casing or may be otherwise guided. The shifting ballast weights are
preferably made of a convexo-convex formation in cross section, but they may be
made of any other suitable shape which will offer but little impediment to progress
through the water. Or, the ballast may be applied in shiftable bulk, such as in
the form or condition of gun-shot, burrs or filings, in which case the bottom of the
angular casing may be fitted with a raised part adapted to graduate the flow of the
ballast and prevent its being unduly shifted by the motion of the boat. In
the event of the ballast consisting of shifting weights, either or both ends of the
ballast casing may be fitted with rubber or spring buffers to take up the impact of
the weights and prevent injury to the casing. The after end of the casing (farthest
from the centre or pivot upon which the centre board turns) is preferably open and
fitted with a removable cap or the like to enable its interior to be readily got at,
which permits of the ballast being readily increased or decreased at pleasure.
The after part of the slot in the keel of the vessel in which the centre board
moves, is shaped to accommodate the after end of the ballast casing, and its top
opening has a bevilled edge on which a weighted block or lid is placed when the
centre board is down, a smaller swallow-tailed block or lid being used when the
centre board is up.
•
The trunk or case built above the keel of the vessel for the accommodation of
the centre-board, is also made to accommodate the after end of the ballast casing;

page_text: its top end is left open at its after part to permit of the capped end of the ballast
casing being readily got at when the centre-board is up, and of the said weighted
and swallow-tailed lids being readily placed in and removed from position on top of
the keel.
Dated this 27th day of December 1893.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Centre-board or Drop-keel Apparatus for Yachts and,
the like.
I, FRANCIS WENTWORTH BREWSTER, of Chesterfield House, West Cliff
Gardens, Bournemouth, Gentleman, 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 relates to the ballasting of centre-boards or drop-keels used in
yachts and the like, and consists in the combination with the centre-board of
adjustable ballast adapted to automatically shift along the lower edge or part of
the centre-board both upon the lowering and upon the raising of the centre board,
so that the ballast will always occupy its lowest and most useful position whether
the centre-board be up, down or at an intermediate position.
In the accompanying drawings-
Fig. 1. represents, in sectional elevation, the keel of a yacht and the centre-
board trunk, and in elevation, a centre-board embodying the present improvements.
Fig. 2, represents a sectional plan, with the top of the trunk removed.
Fig. 3, represents a sectional elevation on the line 1—2 Fig. 1.
Fig. 4. represents an elevation of Fig. 3, the near sides of the trunk and of the
keel and ballast-carrying bulb being removed.
Fig. 5, represents a like view to Fig. 4 of a modification, and-
Fig. 6, represents a sectional elevation of a further modification.
a, is the centre-board, which is pivotally supported at a', in a trunk b, and is
lowered and raised as required by a chain a², guided by a sheave or pulley a³, all in
a usual manner.
To the lower and after edge or part of the centre-board, I apply a ballast-
carrying tubular closed bulb c, of an angular formation (Figs. 1 and 6) or of an
equivalent curved formation in side view, and preferably of an elongated elliptical
or double convex formation in transverse section (Fig. 3).
The tubular closed formation of the bulb enables it to contain the shifting
ballast d, with an unimpeded facility of shifting as the manipulation of the centre-
board may occasion; its angular formation enables such ballast to shift to the
respectively lowest part of the centre-board when raised or when lowered or when
at any intermediate position; and its elliptical formation and smooth exterior
enable it to pass through the water without offering any appreciable resistance to
the way of the yacht.
The bulb is preferably made in longitudinal half-parts (Fig. 3,) which may be
rivetted or otherwise secured together and to the lower and after edge of the
centre-board (Figs. 3 and 4) so that the whole width and depth of its interior may
be open to and available for the ballast.
Or, the half-parts of the bulb may be applied to the lower part of the centre-
board so that the latter will be continued longitudinally and vertically through the
bulb so as to divide its interior into equal lateral compartments.
The ballast d, may, advantageously, be made of lead or of other heavy, and
preferably inoxidizable metal and may be adapted to shift by rolling along the
bulb (Figs. 1, 3 and 4) in which event, it is made approximately of the cross

page_text: sectional form of the bulb, and circular in side elevation, and is formed with
trunnions d', or adapted with runner-wheels, roller-bearings or anti-friction_wheels
adapted to rest and roll on or in rails or guideways c', which may be formed on or
secured to the inner sides of the bulb c, and are closed at each end at a distance
from the bulb ends to prevent the ballast from impact against the latter.
Or, the ballast may be adapted to shift by sliding along the bulb (Fig. 5,) in
which event it is made of an elongated form in side elevation, and is formed, at each
side, with extended bearings d, adapted to slide along rails or guideways c¹.
Or, the ballast may consist. of gun-shot, quicksilver or other materials of greater
specific gravity than water and adapted to shift in molecular or liquid-like bulk
along the bulb (Fig. 6) or it may consist of water, in any of which events the
guide-ways c, would not be required, and the ends of the bulb may be fitted with
dash-plates e, serving to prevent sudden impact of such ballast against the
bulb ends.
The after end of the bulb is preferably fitted with a hinged or sliding and
suitably secured cap c³, in order to permit of access being readily obtained to the
interior of the bulb when in its raised position (vide the dotted lines Fig. 1.) so that
ballast may be added or removed if required.
The trunk b, is shaped and the keel e, is slotted as at e¹, to accommodate the
centre-board and its ballast-carrying bulb (Figs. 1 and 2).
The keel is also formed with a seating e, to accommodate exchangeable weighted
boards or metal blocks e³, respectively adapted to close the bulged end of the slot e¹,
when the bulb b is down (vide the full lines Fig. 1) and when it is up (vide the
dotted lines Fig. 1).
The trunk is also made with a top opening b', through which the bulb can be
got at, and the boards or blocks es, adjusted, and which is normally closed by a
lid 62.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
:-
In yachts and the like-
1. In combination, a pivoted centre-board or drop-keel and adjustable ballast
contained therein and adapted to automatically shift along the lower edge or part
thereof to the lowest part thereof upon the centre-board being raised or lowered,
as set forth.
2. In combination, a pivoted centre-board, a ballast-carrying tubular closed bulb
of an angular or curved formation secured to the lower edge or part of the centre-
board, and contained adjustable ballast adapted to automatically shift along and
within the bulb to the lowest part thereof upon the centre-board being raised or
lowered, and means of raising and lowering the centre-board, as set forth.
3. In combination, a pivoted centre-board, a ballast-carrying tubular closed bulb
of an angular or curved formation secured to the lower edge or part of the centre-
board and formed with inner rails or guideways and contained adjustable ballast
adapted to automatically roll or slide along and within the bulb to the lowest part
thereof upon the centre-board being raised or lowered, and means for raising and
lowering the centre-board, as set forth.
Dated this 24th day of October 1894.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.