 |
Description  |
|
|
BACKGROUND AND PRIOR ART
This invention pertains to small keelless boats. Such boats, because they
offer little resistance to leeway, cannot be sailed on the wind and canoes
especially are difficult to paddle on a straight course, particularly by a
single paddler. Lee boards have been employed to minimize leeway in
sailing canoes, but these have not been entirely satisfactory, among other
reasons, because they often occupy valuable space in the vessel.
SUMMARY OF THE INVENTION
It is an object of this invention to provide readily installed, adjusted,
and detached single and multiple-keel assemblies for use on keelless small
boats.
A keel assembly comprises:
(a) Two or more straps having a first and a second flat side and means for
securing said straps to said boat above the waterline, said strap being of
a length to pass athwart the bottom of the boat with the first flat side
against the boat;
(b) on the second flat side of each of said straps, one or more keels
consisting of flexible bands crossing said straps on edge at about a righ
angle;
(c) at each crossing a bracket, said bracket being attached to the keel and
to the second flat side of the strap, so as to deploy the keel outwardly
from the strap at the point of attachment, at an angle of about 45.degree.
to 90.degree..
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation view showing one embodiment of the invention applied
to a canoe.
FIG. 2 is a bottom plan view of the same canoe showing, in broken lines, an
assymetric placement of the keel, for example, to correct the assymetric
thrust of a single paddler.
FIG. 3 is a cross sectional view taken at plane 3--3 of FIG. 1 showing an
arrangement of keel, flexible bracket and strap in accordance with the
invention.
FIG. 4 shows the features of FIG. 3 in greater detail and, in broken lines,
demonstrates sidewise displacement of the keel by elastic bending of the
bracket as would occur, for example, on collision with an underwater
object. Especially when double keels are employed as shown in FIG. 7, the
bracket may be so selected as to deploy the keel outward to as much as
about 45.degree. from vertical. In a double keel embodiment as described,
the keel shown in broken line in FIG. 4 would represent the starboard
keel. Double keels may thus be splayed outward making easier the beaching
of the boat.
FIG. 5 is a cross sectional view taken at plane 5--5 of FIG. 1 showing one
means for securing a strap to the boat above water line 11.
FIG. 6 shows the features of FIG. 5 in top plan view.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to this invention there is provided a detachable keel assembly
which can be applied to a wide range of keelless boats. For example the
assembly can be installed and employed on small boats up to about 25 ft.
(7.6 m) overall length having bottoms ranging in shape from quite flat, as
seen in some small fishing boats, to those of hard shine dingies, to
bottoms which, in section, approximate a circle of beam diameter.
Particular application is seen in canoes, especially white water canoes,
and kayaks.
Turning now to FIG. 1, one sees a preferred application of one embodiment
of the invention, wherein a single keel is attached to canoe 10. Keel 12
is a band of material. The choice of material is not critical. Both
metallic and nonmetallic materials are satisfactory. Among metallic
materials, stainless steel sheet, say 1/16 in. (1.6 mm) thick, can be used
and is preferred over aluminum because the latter may be attacked by salt
water. Nonmetallic materials are generally preferred, however. Among this
class, some satisfactory materials are reinforced figerglass, epoxy
plastics, polyester resins, polyethylene, and other plastics such as poly
(methylmethacrylate). Most preferred is extruded plasticized poly (vinyl
chloride) and poly (acrylonitrile-butadiene-styrene) terpolymer. The cross
sectional shape is preferably a simple rectangle although other shapes
incorporating, for example, reinforcing ribs may be present.
The keel material, dimensions, and cross section are selected such that the
installed keel does not bend excessively or break in use. These variables
are readily determined by trial.
It is useful to be able to bend the keel or even roll it up for storage,
for example, under the gunwale of the boat. Thus flexible materials are
preferred.
The dimensions of the keel depend in part on the use to which the boat will
be put. If it is intended to use the invention keel to make it easier to
paddle in still water, then a 15 to 21 ft. (4.6 m -to 6.4 m) canoe might
employ a 1/8 in. (3.2 mm) thick band of extruded plasticized poly (vinyl
chloride) 1.5 in. (3.8 cm.) wide and 7 ft. (2.1 m) long. The dimensions
are generally not critical and may be varied widely without departing from
the spirit of the invention.
The above dimensions are those which one might select for use in waters
where collision with underwater objects is likely. If such collision is
less likely one might select a keel which is somewhat shorter, whereby to
facilitate turning, and somewhat wider, say 4 ft. (1.2 m) long and about 3
in. (7.6 cm.) wide. Should one wish to sail the canoe one would employ a
keel usually of somewhat greater area, and preferably somewhat shorter.
Compromise between increased likelihood of collision with underwater
objects will often be accepted in exchange for increased ease of handling.
Such a keel might be 2 ft. (61 cm.) long and 8 in. (20 cm.) wide. The keel
is normally so placed, as is known, to be more or less under the center of
effort of the sails and generally at or near the midpoint of the
waterline.
The keel, however selected, is attached to straps 14 via brackets 16. The
straps characterized by having two flat sides may be of any flexible
material of adequate strength. One might employ leather, natural or
synthetic rubber, preferably fiber reinforced, plasticized poly (vinyl
chloride), stainless steel strip and the like. Preferred is reinforced
rubber. Some elasticity in the straps is desirable to maintain tautness in
the straps.
At least two straps are needed to hold the keel in position. Depending on
the stiffness and length of the keel, more straps will be used. For
example, a 7 ft. (2.1 m) keel would normally employ three straps as shown
in drawings. Under heavy sail the same canoe might employ four straps.
Straps are placed, as shown in figures, with one flat side against the
boat.
For convenience in installing and adjusting the keel, straps 14 are secured
to the canoe above the water line. In some cases it may be desirable
simply to attach the two ends of a strap to each other, for example, by
means of a buckle. As the keel in this embodiment is ultimately held in
place by friction of the strap on the boat and the straps are buckled, for
example, above the waterline, this embodiment is intended to fall within
claims directed to the straps being secured above the waterline, as
described below.
Various means may be used for securing the straps to the boat, e.g. the
gunwale, such as cleats of various kinds, as are known to the seaman,
buckles, snap fasteners and the like. As illustrated in FIGS. 1, 5, and 6,
the straps are secured by means of button 20 attached to gunwale 18. One
of the the holes 22 is drawn over button 20 thus securing the strap. Keel
12 is attached on edge to straps 14 via bracket 16. Various means may be
employed for attachment such as cementing, screwing, or, as illustrated,
in FIG. 4, by riveting.
An important advantage is conferred on the invention assembly by selecting
bracket 16 to be flexible so that on collision, with, for example, an
underwater object, the keel can yield, as shown in FIG. 4, without damage
to the keel or the canoe. The bracket can be selected from various
materials such as stiff rubber, flexible plastic such as poly (ethylene)
in thick section, or, as is perferred and illustrated, spring steel.
The arrangement of elements are here described results in the single-keel
configuration of FIG. 3 wherein the bow or stern sections are shown as
items 18. The invention is not limited, however, to embodiments comprising
a single keel. Using the same materials and methods, two parallel keels
12B can be provided as illustrated in FIG. 7. Furthermore, the double
keels 12B may be oriented outwardly as shown in FIG. 4 in broken line such
that keels makes an angle with the vertical of about 45.degree.. This
embodiment, which is comprised in claims has distinct advantage to the
boatman who must beach his boat from time to time.
In some cases it may be useful, for example on flat bottom motor powered
boats, to use more than two keels, possibly as many as five.
The single paddler in say a white water canoe normally maintains a straight
course only with expenditure of considerable effort because of windage on
the freeboard and unsymmetrical thrust from the single paddle. FIG. 2
illustrates a strategy; for overcoming this problem wherein the keel
itself counteracts the forces causing the canoe to go off course. In the
embodiment of FIG. 2, the canoeist has displaced the forward and aft
straps. He could also achieve similar effect by displacing only the
forward strap and bending the keel.
The keels are removed by reversal of the installation process.
Although this invention has been illustrated in connection with canoes, it
is understood that other boats within the limits set out above can benefit
equally well from application of the invention principles.
* * * * *
|
|
 |
|
 |
Description |
|
