Improvements in and relating to Drop Keels for Yachts and like Vessels.
Year: 1894

page_text: Date of Application, 22nd Aug., 1894
Complete Specification Left, 30th Apr., 1895-Accepted, 1st June, 1895
PROVISIONAL SPECIFICATION.
Improvements in and relating to Drop Keels for Yachts and like
Vessels.
I, WARINGTON BADEN POWELL of 3 Paper Buildings Temple in the City of
London and County of Middlesex, Barrister-at-Law, do hereby declare the nature
of this invention to be as follows:-
My invention relates to drop keels for yachts and similar vessels, its object being
to combine the ballasting properties and the lateral resistance of the fixed bulbed
fin keel with the advantages of the lifting centre board or plate and consists
essentially in pivotting a plate, preferably of Bull's metal carrying at its
bottom end a bulbed keel preferably of lead between two parallel plates
also preferably of Bull's metal which are connected together top and bottom
in such a manner as to allow the central plate carrying the bulbed keel to
work freely between them. The two parallel plates being pivotted to the usual
centre board case or housing at or near the keel line of the vessel. The central
plate carrying the bulbed keel is so pivotted to the two parallel plates, that when
the upper portion of the same behind or aft of its pivotal connection to the centre
board case or housing is pulled or drawn forward by any suitable tackle or gear or
when the bulbed keel comes in contact with an obstacle the parallel plates together
with the central plate suspended and pivotted between them will be raised through
the case or housing so that what were the forward edges of the parallel plates
become the bottom edges and will lie parallel with the keel line (if desirable the
above arrangement may be exactly reversed) whilst the central plate carrying the
bulbed keel will be raised in a vertical and parallel direction till its bulbed keel is
level with and parallel to the keel line.
It will thus be seen that the bulbed keel is always in a horizontal position and
its centre of gravity is only very slightly altered in a longitudinal direction so that
the trim of the vessel is not materially affected when the bulbed fin keel is in its
raised or lowered or any intermediate position. The central plate carrying the
bulbed keel is preferably provided with a quadrant slot with which engages a pin
or stud carried by the parallel plates, to limit the movement of the said plates with
respect to each other. A pawl or equivalent device may be employed to engage
with a shoulder on the upper part of the central plate to keep it fixed when at its
lowest position. Suitable means are also provided for looking the central plate to
its two outside enclosing plates at its highest or any intermediate position.
Dated this 20th day of August 1894.
COMPLETE SPECIFICATION.
Improvements in and relating to Drop Keels for Yachts and like
Vessels.
I, WARINGTON BADEN POWELL of 3 Paper Buildings in the City of London
and County of Middlesex, Barrister-at-Law 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:-
My invention relates to drop keels for yachts and similar vessels, its object being
ונ...rD

page_text: to combine the ballasting properties and the lateral resistance of the fixed bulbed
fin keel with the advantages of the lifting centre board or plate and consists
essentially in pivotting a plate, preferably of Bull's metal, carrying at its bottom
end a bulbed keel, preferably of lead, between two parallel plates, also preferably
of Bull's metal, which are connected together top and bottom or top only in such
a manner as to allow the central plate carrying the bulbed keel to work freely
between them. The two parallel plates are pivotted to the usual centre board
case or housing at or near the keel line of the vessel. The central plate carrying
the bulbed keel is so pivotted to the two parallel plates, that when the upper
portion of the same behind or aft of its pivotal connection to the centre board case
or housing is pulled or drawn forward by any suitable tackle or gear or when the
bulbed keel comes in contact with an obstacle, the parallel plates together with the
central plate suspended and pivotted between them will be raised through the case
or housing so that what were the forward edges of the parallel plates become the
bottom edges and will lie parallel with the keel line (if desirable the above
arrangement may be exactly reversed) whilst the central plate carrying the bulbed
keel will be raised in a vertical direction till its bulbed keel is level with and
parallel to the keel line.
It will thus be seen that the bulbed keel is always in a horizontal position and
its centre of gravity is only very slightly altered in a longitudinal direction so that
the trim of the vessel is not materially affected when the bulbed fin keel is in its
raised or lowered or any intermediate position. The central plate carrying the
bulbed keel is preferably made with a quadrant slot with which engages a pin or
stud carried by the parallel plates to limit the movement of the said plates with
respect to each other. A pawl or equivalent device may be employed to engage
with a shoulder on the upper part of the central plate when it is desired to prevent
the bulb from oscillating when at its lowest position. Suitable means are also
provided for locking the central plate to its two outside enclosing plates at its
highest or intermediate position.
I will now more particularly describe my invention making reference to the
accompanying drawings in which :-
:-
Figure 1 is a view in side elevation of one form of a drop keel constructed
according to my invention and
Figure 2 is a view in front elevation thereof.
Throughout these views similar parts are marked with like letters of reference.
A designates the central plate carrying at its lower end the bulbed keel B, which
is preferably of lead and formed in two pieces and fixed on to the plate A by
means of bolts b, b, etc. as shown. This plate A is pivotted at a to the two parallel
enclosing plates C, C which are connected together at their upper ends by a
distance plate C, this plate together with the plates C, C are preferably cut away
as shown at c, c for the purpose of reducing weight and are provided with cranked
arms C2, C² to take a grip-bearing on to the top of the usual centre board case or
housing X (as shown in dotted lines in Figure 2) when the bulbed keel is at its
lowest position.
The plates C, C are also connected together at their lower ends by a plate or
bolt c' and are pivotted at by a suitably packed through bolt to the centre board
case or housing X at or near the keel line x-x of the vessel. The probable load
water line of the vessel is shown by the dot and dash line y-y.
It will thus be seen that when the upper portion of the plates C, C and C¹ are
drawn or pulled forward-the forward edges of the plates being marked A* and C*
respectively by means of any suitable tackle or gear passing round the sheave c³
or when the bulbed keel comes into contact with an obstacle, the parallel plates
together with the central plate A will be raised through the case or housing X so
that what were the forward edges of the plates C, C become the bottom edges and
will lie parallel with the keel line, whilst the central plate A will be raised
practically in a vertical and parallel direction till the bulbed keel B is level with

page_text: and parallel to the keel line as shown in dot and dash lines on Figure 1 of the
accompanying drawings. It will thus be seen that the bulbed keel B is always in
a horizontal position and its centre of gravity is only very slightly altered in a
longitudinal direction so that the trim of the vessel is not materially affected when
the bulb keel is in its raised or lowered or any intermediate position. The
plate A is preferably provided with a quadrant slot a¹ with which engages a pin or
stud c* carried by the plates C, C to limit the movement of the said plates with
respect to each other and to prevent the plate A and bulb B from dropping off
should the bolt a be accidentally broken. A shoulder a* is preferably formed on
the upper edge of the plate A to engage with a shoulder c* formed on the distance
piece C to limit the movement of the plate A. A pawl D (shewn only on
Figure 1) pivotted at d to the centre board case or housing or keel is adapted to
engage with a shoulder a³ formed on the upper part of the plate A to keep it fixed
when desired to prevent oscillation when at its lowest position. In any inter-
mediate position of hoist the bulbed plate can oscillate freely unless one of the
following stops are used. The central plate A and its two outside enclosing
plates C, C are provided with holes a³ and c³ respectively which coincide with
each other when in the highest raised position as shown in dot and dash lines, so
that a bolt or rod may be inserted therein to lock them together in their raised
position.
Holes in the plates C, C and holes a' in the plate A may also be provided to
allow a bolt or rod to be inserted to lock the plates together in the highest or an
intermediate raised position.
It is advisable to provide an aperture a in the plate A for the insertion of a bar
or block in the half raised position, the ends of said bar resting on the top of the
centre board case or housing and is preferably adapted to grip the same and thus
take the strain and weight off the pivot c³ thus forming a rigid support for the bulb
and its plate but without preventing free upward or lifting motion, in case the keel
should strike the ground or a submerged obstruction.
It will be understood that instead of using one plate to carry the bulbed keel
I may use two plates in which case they will be pivotted to and suspended from
one plate instead of two as herein before described.
By disconnecting the bolts and a and unshipping the bulbed plate A or
plates, the plates C, C or plate remain and are useable as an effective pivotted
centre-board.
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. A drop keel for yachts and like vessels consisting essentially of a plate or
plates carrying a bulbed keel pivotted to and suspended from two plates or a plate,
the said plates or the said plate being pirotted to the centre board case or housing
as set forth.
2. In a drop keel for yachts and like vessels of the type claimed by Claim 1,
the use of a quadrant slot and stud as and for the purpose set forth.
3. In a drop keel for yachts and like vessels of the type claimed by Claim 1,
the use of shoulders a and c on the plate A and distance piece C' respectively as
and for the purpose set forth.
4. In a drop keel for yachts and like vessels of the type claimed by Claim 1 the
use of a pawl such as D as and for the purpose set forth.
5. In a drop keel for yachts and like vessels of the type claimed by Claim 1,
the use of a bulbed keel such as B constructed as herein before described and
shown.
6. In a drop keel for yachts and like vessels of the type claimed by Claim 1,
the use of coinciding holes such as a³, a and c, c in the plates A and C, C
respectively as and for the purpose set forth.

page_text: 7. In a drop keel for yachts and like vessels of the type claimed by Claim 1 the
use of an aperture such as a' in the plate A as and for the purpose set forth.
8. A drop keel for yachts and like vessels constructed arranged and adapted to
. operate as herein before described and shewn on the accompanying drawing.
Dated this 14th day of March 1895.
WARINGTON BADEN-POWELL.