CA2020363A1 - Downrigger with leveraged line clamp and fish attracting means - Google Patents

Abstract

DOWNRIGGER WITH LEVERAGED LINE
CLAMP AND FISH ATTRACTING MEANS
ABSTRACT OF THE DISCLOSURE
A weighted downrigger for troll fishing provides a vertical stabilizing fin having a medial rotatable member to aid in attracting fish and a jaw-type line clamp to releasably fasten a fishing line inwardly adjacent a lure. The stabilizing fin and rotating element both provide light reflecting surfaces, which may additionally be colored, to optically attract fish. The rotating element provides additional acoustical-like attraction for fish. The line clamp provides adjustable tensioning structure and an elongate lever arm carried by one jaw to magnify the force of a fishing line trailing from the lever arm to cause clamp release responsive to less force on the trailing end of a fishing line than on the inboard end of such line.

Description

20203~3 :` ,.~, Our invention relates generally to weighted downriggers for troll fishing and more particularly to such a downrigger that has a vertical stabilizing fin with means to attract fish and a leveraged line holding clamp. -In troll fishing it commonly is necessary to maintain a fishing lure at substantial depths beneath the surface of a --~
body of water to effectively catch fish. Commonly with most smaller game fish, it is not feasible to maintain sufficient weight on a fishing line itself to establish a lure at appropriate depths because of the substantial drag of both the fishing line and weighting elements in moving through water, especially when considered in comparison to the size of ;~
a fish to be caught and the forces that might be created on a fishing line by a caught fish. Responsive to this problem so~
15 called "downriggers" have come into use to maintain fishing r::;~',~'"'l'~,";"` ''', ',,' lines at appropriate fishing depths without disrupting other ,:.'r~
fishing processes. ` `i ~`
These downriggers are suspended by a downrigger line, separate from a fishing llne and carried by a support structure on~a boat. This independent downrigger suspension eliminates the problem of downrigger drag on a fishing line, as that drag "
is carried by the downrigger line. Wlth downriggers an associated fishing iine is fastened to the dowinrigger by~some type of releasable clamp that holds the fishing line at a point sp;acedly inwardly adjacent a lure. Such line clamps are relea;sable upon appropriate force being exerted upon either end ;;of a fishing line passing away from the clamp. Our invention provides an improved downrigger of this type.
Tr~aditional downriggers heretofore known generally have ~ 3 2020363 ~

not been concerned with features other than providing sufficient weight to serve their purpose. Such downriggers are , ~ ,- ,.
not of particularly streamlined shape and often do not provide suspension lines that minimize water resistance, which cause substantial drag forces when the downrigger moves through water. Additionally such downriggers have not been stable in ;
maintaining a uniform course in moving through water, but ;~
rather have been erratic and often have moved in an irregular course, particularly by undulating in a horizontal direction. i~

Such prior downriggers generally have had sufficient drag in moving through water that they often are not maintained ;~
beneath a supporting boat during trolling activities, but rather trail substantially rearwardly of a boat. This is not `;
desirable as many fishermen that use downriggers also use display type depth-finding devices, and it is preferred that a downrigger be observable by such devices. Excessive drag may move a downrigger out of the cone of observation of depth ~ ",~
finders.
Our invention seeks to solve these problems by providing a 20 downrigger that has a high density body with a streamlined ;~
shape including an oblately hemispherical nose to aid passage ;`~
through water at the relevant speeds to reduce drag.
Additionally, we provide a rélatively low dens'ity verticai fin of~substantial area extending from the body to aid stabilization. We use a suspension line of small cross-section for th~e strengths required. These features tend to provide a downrigger that upon motion through water remains nearly vertically beneath its point of suspension and maintains a .... ..

relatively stable and uniform course of passage through water.

Known downriggers generally have not provided any means to : ~

2020363 ~-attract fish to increase the probability of fish finding a lure associated with the downrigger. Our downrigger provides both `~
optical and audio-like fish attracting means. The stabilizing fin has surfaces formed of highly light reflective materials, such as are often used on fishing lures, so that the fin is highly visible to fish. The substantial area of the stabilizing fin and its motion through water both aid to enhance this feature. Additionally, we provide a rotating propeller in the medial portion of the stabilizing fin. This propeller also has surfaces that are formed of highly light reflective materials and it may be colored to provide further `~
potential optical attractiveness for the device. These -~
features are further enhanced by the rotary motion of the propeller which tends to cyclically move the reflective surfac~es at different angles to a light source to produce a complex reflective pattern of continuously changing nature.
The propeller additionally provides an "acoustical"
attractant for fish by generating fish sensible pressure waves n the water through which it passes by causing cavitation, 20 otlon or otherwise. Fish are more attracted to the vicinity ""~'i';"""`:''i'-'. '," ' ~'~'.:;
of~our downri~gger than they are to the vicinity of downriggers not having these features, apparently by reason of the curiositg of fish an'd their instinctual behavi;or associating ~
brlghe,~shiny surfaces and pressure disturbances with potential ~`~25~ sources of food.
; Our invention provides a line holding clamp that has lever ~ ?~
means to multiply the force on the lure end of a line to cause release of the clamp, while the clamp yet requires a substantially larger force on the supported or inboard end of 30 ~ the line to cause release. Line clamping devices of known 202~3~
.

downriggers traditionally have provided two clamping surfaces biased in surface adjacency, but movable against their bias to release a line carried therebetween. With such clamping devices the same force on either end of a fishing line being held by such clamp will release the line. If a relatively small fish is caught by a lure carried by a fishing line held in such a clamp, the force that fish might exert upon the ;~
line often is not sufficient to cause the clamp to release. ; -~
Many such prior clamps have allowed adjustment of the required clamp release force, but the drag of a line extending between fishing line support and a clamp was so large that that drag necessarily determined the lowest amount of force that would be required to release the clamp. Such line drag force often is substantially greater than the force caused by a small fish hooked on a lure, so if a small fish is caught it may not release the clamp, but rather would be dragged behind the downrigger with no knowledge of a fisherman that it had been ~~
caught.
Our invention provides a lever arm, extending from one jaw 20~ of an adjustable clamp, that carries a fishing line extending ~ ~` `
to a lure. The length of this lever arm allows the force ;~
exerted on a lure to be magnified in its action on the clamp jaw CarryiNg it, so that a fishing line will be releasediby small forces caused by a small fish that are less than the line ~;25 drag force. The lever arm of our clamp may be adjustable or releasably positionable to allow the use of plural lever arms of different lengths with the same clamp jaw to provide different mechanical advantages. `~
~ Our invention resides not in any one of these features 30 per se, but rather in the synergistic combination of all of ~ ~ . . .: .: :: , ~: ~ . .~; :.

202~363 them to provide the structures and the functions necessarily flowing therefrom, as herein specified and claimed. In providing such a device, it is~
An object of our invention to create an improved downrigger for troll fishing that has a dense body of streamline shape for regular motion through water with minimal drag so that the downrigger is carried substantially `~
below a boat supporting it. -A further object of our invention is to provide for such a downrigger a relatively thin, vertically oriented stabilizing fin of substantial area to aid regularity and stability of motion of the downrigger through water. ;~
A further object of our invention is to provide such a stabilizing fin that has a medial void wherein a propeller is carried to rotate responsive motion of the downrigger through water to aid in attracting fish.
A further object of our invention is to provide such a ~ - "
~; stabilizing fin with light reflective surfaces on both the fin and propeller to provide optical attraction for fish.
A still further object of our invention is to provide a ~ `
a llne clamp in a position from which a released fishing line will not be entangled with the downrigger structure. 'I''')~'','~''':r'','~,~`,''','',- ''' '~
A still further object of our invention is to provide such `~
a line clamp that has opposed adjustably biased jaws to clamp a fishing line therebetween, with the rearward jaw having a lever arm to releas?bly support the lure end of a fishing line and magnify the force on that end of the fishing line required to ~ ;~-cause release of the line from the clamp.
A~still further object of our invention is to provide such 3~0~ a downrigger and accessories that are of new and novel design, 2020363 ~ ~ -~ .... . ~ ,, .
of rugged and durable nature, of simple and economic `~
manufacture and otherwise well adapted to the uses and purposes for which they are intended. Other and further objects of our invention will appear from the following specification and accompanying drawings which form a part hereof. In carrying out the objects of our invention, however, it is to be remembered that its accidental features are susceptible of ~r`~
change in design and structural arrangement with only a practical and preferred embodiment being set forth, as is required.
In the accompanying drawings which form a part hereof and wherein like numbers of reference refer to similar parts throughout~

Figure 1 is a somewhat diagrammatic view showing a i~
~ ` ~- :
10ating boat carrying a downrigger of our invention suspended `~
therebeneath with a fishing line releasably attached to the ,~
downrigger.
Figure 2 is an orthographic side view of our downrigger showing its parts, their configuration and relationship.
Figure 3 is a partial isometric view showing the line engaging portion of the lever arm of the line clamp structure.
Figure 4 is a~!medijal!vlertical cross-sectional view through the downrigger of Figure 2, taken on the line 2-2 thereon in the direction indicated by the arrows.
Figure 5 is an orthographlc top view of the downrigger illustrated in Figure 2.
Figure 6 is an orthographic side view of the stabilizer ` -~
fin of our downrigger isolated from its associated structures.
Figure 7 is a somewhat enlarged partial cross-sectional , - ~ . .:
8 ;~

view showing the releasable fastening structure of the propeller parts. -`~
Figure 8 is a partial isometric view of the line clamp showing various parts and their relationship. ;~
Figure 9 is a partial orthographic side view of the line clamp in place on the stabilizing fin.
Our invention generally provides a downrigger having body , ,~ ~ -. ... .
10 supporting stabilizing fin ll which in turn carries medial propeller 12 and rearward line clamp 13. .
Body 10 provides medial cylindrical portion 14 joining ;~
forward nose portion 15 and rearwardly tapering tail portion '~
16. Nose portion 15 is substantially of the hemispherical ;"~
shape illustrated to allow streamline flow over the nose as it ,~
is moved at relatively slow trolling speeds through water.
Rearward body portion 16 tapers to hemispherical end 17 approxlmately half of the diameter of the nose portion. ~ ~ Ai'l~
This body~ shape should be chosen according to known technology to minimize turbulence as the body moves through water. The body is~formed substantially as a surface of revolution with a ~ , flat~bottom portion 18 to maintain the body in an upright - position with some positional stability when it is supported on ~i~ ;
a flat surface. The length of the body is approximately three and one-half times its diameter, and the rearward tapering portlon~constitutes not more than approximately the rearward ~25~ thlrd of the structure, to provide stability with streamlined pa~ssage through water. ~ ~
The upper rearward portion of body lO provides surface l9 ,~`,~ '"'`7 to~ln~terfit with fastening rim 27 of the adjacent stabilizing ~ . . `
fin. The portion of the downrigger body adjacent the fin ~ -~

~30 structure provides appropriate fastener holes (not shown) to ~ ``-~ 9 accept mechanical fasteners extending between the fin structure and the body to releasably position and mechanically '`~
interconnect these elements relative to each other.
The upper medial portion of body lO defines internally ,`~
threaded hole 21 to carry line fastening eye 22 of traditional closed loop configuration. In the instance illustrated, line fastening eye 22 extends through the forward portion of the fastening rim of the stabilizing fin to serve the dual purpose ;~
of providing a fastening device for a s`uspension line and also 10 of releasably fastening the forward portion of the stabilizing ~ ~ ~i fin to the body. For most effective operation the fastening eye should be substantially vertically above the center of ,^
- gravity of the assembled downrigger structure, as otherwise a downrigger may not be stable in its motion through water and 15 may tend to yaw. `~
Stabilizing fin 11 provides relatively thin, planar body -~ 23 of the illustrated somewhat rectilinear shape with rounded co~rner6 24. Forward portion 26 of the fin is configured to ~ f' fit~conformably on the upper rearward portion of body 10. The `;``;`
20 lower part of forward fin portion 26 defines fastening rim 27 extending somewhat horizontally a spaced distance on each side of the fin body to conformably fit against the adjacent portion of the downrigger body to aid fastening of the two elements and ,' also~to~provide additional strength for forward portion 26 of 25 the fin. Plural headed bolts 28 extend through holes defined -r~
in rlm 27 and into threaded engagement with cooperating holes defined in body 10 to releasably interconnect the fin structure with the body. It should be noted that the fin and ~ bottom rim 27 might be so configured as to fit upon downrigger ;~ 30 bodies of different shape than that illustrated, and ~ 1 0 ' ''` ' ' ' ' ~ ' ' 2Q2Q363 ``- ; ~

particularly might be configured to fit upon existing downrigger body structures such as the ordinary spherical ball.
: i .
This allows use of our fin as an additive structure on existing `~
downriggers with only slight and obvious modification.
The upper rearward portion of fin body 23 defines clamp ;-notch 29, with lower edge 30 substantia11y parallel to the axis of downrigger body 10 and forward edge 31 angulated with an upward and rearward slope, as illustrated especially in Figure 6. The size of the clamp notch is not critical, but should not 10 be so large as to compromise the physical integrity of the fin .
structure and preferably is somewhat of the proportion illustrated in the drawings.
i,: . .. .. . .
The medial portion of fin body 23 defines propeller orifice 32 of a shape and size to allow rotation of a propeller 15 carried therein. The forward and rearward edges of the '''';!~'''~`'"''~ "" ' ~ ''"' propeller orifice have inwardly projecting pillar portions 33 each defining in their inwardmost projections cylindrical ~ r:
journaling shafts 34 at a spaced distance from each other. The ~ '~
axes of shafts 34 are coincident and substantially parallel to ~20 the~axis of downrigger body 10 to provide a journaling means `~
for a propeller to be carried thereby.
The stabilizing fin is formed of reasonably rigid, durable material, preferably one of the more rigid and dense ~; ~ polymeric or resinous plastics, metal or wood. The exterior ~25 aurface of fin body 23 is provided with light reflective ~ ` ;~
material that preferably is also light refractive, so that ght impinging upon the surface will be reflected and scattered to provide an optical attractant for fish within a visual range of the structure. The fin surfaces also `~
30~ optionally may be colored to provide additional optical ,,; . ~:-.~;. ~ .-. :

2 0 2 0 3 6 ~
..
attraction for fish. The material of preference for such purpose is reflective sheet plastic material 35 which contains metal flakes or powders to provide a plurality of variously orientated and efficiently reflective surfaces. Such , ~ s~
reflective material may be formed as an integral part of the fin structure or may comprise a coating or relatively thin covering of material adhered or otherwise mechanically attached ,~
to the supporting surfaces, all according to manufacturing ` ;~
methods heretofore known in the fishing lure arts. Various known paint-like coating materials may also provide surfaces of similar nature that are optically attractive to fish.
Propeller 12 provides a rotatably mounted member, carried within propeller void 32 defined by the fin, to rotate .~
responsive to motion of the propeller through water. In the ; ~ -instance illustrated, the propeller comprises two perpendicularly oriented blades having radially outer planar vein~s 36~whlch communicate by medial webs 37 to central shaft 38. As shown in Figure 5, central shaft 38 is angled, '~
symmet~rically at forty-five degrees in the illustrated 2~ 0 instance, to each propelIer blade 36, 37. The central shaft at ~ ~ ni.Y,;
eac~h~o~f~its~;ends defines cup bearings 39 configured and arrayed ~ ,~
to fit upon journaling shafts 34 defined by the stabilizing f1n. l, ~ "
The~entire propeller member must have a peripheral ~ - -configuration to allow it to rotate within propeller void 32 when;carried within that void on shafts 34. Preferably, the p~rope1~1er~1s formed as two similar halves that are releasably interconnected to allow easy placement and replacement or chan~ge~. This can be accomplished, if the propeller structure be~formed of somewhat resilient material, especially such as 12 `~

2020363 ,`~
" , . . ~ , plastic, by the traditional method shown in Figure 7.
Protuberances 40 having a bulbous shape fit with slightly more ` ~
than half of their volume in indentations 41 defined in ~ ~ ;
the opposing member, so that the protruding members may be inserted, with sufficient force to cause resilient deformation, into the indentations which then will capture them and tend to positionally maintain them in fastened condition, until an opposite force unfastens the elements.
Preferably at least veins 36 of the propeller have '~
surfaces of some light reflecting material similar to that of the fin body which is optically attractive to fish. This material optionally may be colored and if so, may be the same or a different color than the stabilizing fin.
The propeller described is not essential and other 15 rotatable propeller structures may serve the purposes of our ~ ~ ~-invention. Preferably the propeller will not have a completely ~ ~ ~ , efficient or completely streamlined rotation, so that rotation causes sore "noise" or disturbance in water it moves through as lt rotates. This dlsturbance apparently creates pressure 20~ vari~ations or similar phenomenon that are perceptable by ~ ~ i b~y~flsh~a~t a dlstance and serve as a type of fish attractant.
i~ P.refer'ably body 10 of our downrigger is formed of some r;sasonably dense material~that can provide necessary weight `25~ without too great a volume. The material of preference is iron~, though lead and other slmilarly dense materials may be used. Lead is not preferred because of its potential for ;~
pollution and its presently perceived adverse environmental and ;~
:."~ , " ~
health~effects. If iron is used for the body, it is preferably -,',?'`~' ~",'-','''`` ,~ ', `

~;30~ covgred on exposed surfaces with some protect1ve coating, such ;

1 3 `i - .
... .... .. . ..

~ ~. :

2020363 i ~-as a paint or plastic, to prevent or retard oxidation caused by ~ ~3, . - ~, water, air or the combination of both. The coating may be colored, light reflecti~e or both to provide additional fish -attractants. `~
The stabilizing fin and propeller are formed of some '`~
~. . ~ .: , .
less dense material of appropriate strength and rigidity preferably, such as a resinous or polymeric plastic. These preferred fin materials may be readily shaped and manufactured, are of relative economy, and are readily ornamented to provide coloration and reflective surfaces.
Clamp 13 is carried in clamp notch 29 defined in the upper rearward portion of stabilizing fin 11. As seen especially in Figure 8, the clamp comprises forward jaw body 42 and spacedly .
adjacent rearward jaw body 43 interconnected by adjustment stud I5 44 extending from structural communication with the rearward ;~
jaw body through an appropriate hole in the forward jaw body and a spaced distance therebeyond. The lower portion of each jaw~bo~dy 42, 43 defines a medial slot 45 to allow the jaw body to~fit over lower edge 30 of clamp notch 29, as illustrated in ZO Figure 9. The jaw bodies are fastened to the fin by adhesion or~;~s1mi1ar~mechanical joinder. Adjustment stud 44 carries ~ ' cylindrical compression spring 46 about its shank between rearward clamp body arm 43 and adjustment nut 47 which is ;~
threadedly engaged on the end portion of adjustment stud 44.
25~ Sim1lar clamp pads 48 are carried by the end parts of the forward and rearward clamp bodies on their adjacent upper ~
surfaces in such positions that the clamp pads meet in surface ''r,~'` "S.. ' . .'}~'' adjacency when adjustment nut 47 is in a relaxed outward position on the adjustment stud.
The clamp body elements are formed of semi-rigid, 202~363 , ~
. .. ~. ~
. .
resiliently deformable materials, such as resinous or polymeric `~
plastics or metal, and clamp pads 48 are formed of material that has a higher frictional surface, such as elastomeric plastics or rubber. With this constituency and the structure ;~
' . ' !: , i ~ ~
described, the clamp pads may be adjustably positioned relative to each other with varying biasing force therebetween responsive to positioning of adjustment nut 47 on adjustment stud 44, to allow the pads to hold a portion of a fishing line therebetween with varying amounts of force required to cause lO its release, as herein described. ~ !~
Elongate line arm 49 is carried by frictional engagement in a hole (not shown) défined in the upper portion of rearward ~ ~ r clamp body 43 and extends a spaced distance upwardly therefrom. ~,~,'r~, ~,,'~,''''~','~',`'1~,,, Preferably the line arm, the rearward clamp body 43, or both ~;t.:'.'~.j:,',,;,',,,''", '~ ~;
are angled slightly rearwardly in their upper portions to provide easier release of a line carried by the line arm, but ~ ;~
this is not necessary to our invention. The outer end portion af the line arm carries line fastener 50, which in the form illustrated is a piece of hollow resiliently deformable tubing 2~0~def1n1ng in its outer end opposed cooperating line carrying slot~s~ 5-I with orientation substantially parallel to the axis of the downrigger body and the fin. The length of the line arm may vary to1provide Idififerént amounts of leverage to act upon the clamp. ;
25~ Having described the structure of our invention, its use -`
and function may be understood.
:, i :
~ A downrigger is formed according to the foregoing `` - ~ ~
::: ~ ~:: : . , specification. As illustrated particularly in Figure l, outboard end of downrigger line 53 is fastened to fastening eye .: - :
~;~ 30 ~22. ;The inboard end of the downrigger line is carried by ~ -...' . ~ ...

`15 2020363 ~
. . .
; . . .
~ .
downrigger suspending structure 54 supported on boat 55.
Fishing line 56 carried on traditional rod and reel structure 57 in boat 55 supports lure 58 in its outboard end part. The ;~
fishing line spacedly inwardly of lure 58 is folded upon itself to form a somewhat "U" shaped configuration, and that "U"
shaped portion is positioned between clamp pads 48 with both line ends extending somewhat upwardly therefrom. The lure end 56a of the fishing line is then brought upwardly along line arm 49 and positioned in line slits 50 defined in line fastener 50.
The lure end 56a of the fishing line is allowed to trail from the line fastener. In this condition, the outrigger structure is ready for placement in a body of water for operation.
In its operative mode, the downrigger and attached fishing line are placed in the water adjacent boat 55 supporting them. ~r~
The fishing line is maintained so that it can feed freely from rod and reel structure 57. Downrigger line 53 is then payed ;~ out to lower the downrigger to the desired depth below boat 55. ~ i`
As this occurs, fishing line 56 will move downwardly with the downrigger by reason of its interconnection therewith. The ~ ~
20 downrigger line is fastened relative its support structure to ~ -j-maintain downrlgger posltion and boat 55 is moved on the surface of water course 59 supporting it in a traditional troll fishing fashion. As this occurs, lure end 56a of the fishing line will trail behind the outrigger to move lure 58 carried by ; `
it to act in substantially the same fashion as the lure would act were it used in a troll fishing operation without the ~, - ~ .,., ;., ~,:
downrigger.
As the downrigger is moved through water, stabilizing ~ -~

fin ll will provide a light reflective surface and propeller : .: ~
30 structure 12 will provide a plurality of moving light ``

202~363 : ~

reflecting surfaces, all to cause an optical attraction for fish in a visually perceptive range of the device. The motion of the downrigger through water will cause rotation of propeller 12 and that rotation will cause variations in pressure in water surrounding the propeller, somewhat in the nature of sound waves in a gaseous medium, that are perceptable to fish. These pressure variations serve as an additional attractant to fish within their perceptable range.
As the dowr.rigger structure is pulled through water, ~ ~
10 downrigger line 53 and fishing line 56 will have some ~ ~i -resistance to motion through the water and because of their resilient nature will generally tend tô form rearwardly concave .
curvilinear configurations, such as illustrated in Figure 1.
The exact nature of these curves depends upon various parameters, such as line width perpendicular to the course of motion, line resilience, weight of the downrigger, speed of motion and the like. This resistance is substantial and with ,'~
an ordinary fishing line of average submerged length at normal ~; troll fishing speeds will cause a force of several ounces and ~^~' . ,.',~ ,~ ' often more than a pound. The force exerted upon fishing line 56 by clamp pads 48 must be sufficient to counteract this resistance or drag force of the line to maintain the line fastened within the clamp.
If a relatively small fish is caught on lure 58, the ~ ~ ;
~25 forces caused by that fish on lure end 56a of the fishing line may not be so great as the force required to maintain the ,~
fishing line in the clip. In the past with fishing line clamps --~
not having the leveraged line arm of our invention, such a small f1sh would be undetected and would be dragged behind a 2020363 ;~

downrigger until the downrigger was taken from the water and `;~
the fish then discovered. -~
With our invention, lure end 56a of a fishing line is carried by line fastener 50 at the outer end part of ]ine arm ` ;~
49. This line arm creates a lever to magnify forces on the lure end 56a of a fishing line that causes release of the line from the clamp structure. The force created on the lure acts `, through a lever arm extending from line fastener 50 to the point of mounting of that clamp arm on fin 11, whereas the ;~
lever arm for the other clamp arm is from its fastening pad to the point of mounting on fin 11, which is less substantially by the length of the line arm. Since line arm 49 is releasably positionable, various line arms of differing lengths may be r~
interchanged to regulate mechanical advantage of this leverage. For normal fishing, the advantage preferably is maintained in a range of about two to five to one.
With our invention then, even a small fish caught on a lure releases the clamping structure and the event is thereby annunciated to a fisherman who can separately reel in both the downrigger structure and fishing line and reassociate both for future operation to avoid the frustrations and time loss of trolling with a small fish caught on a lure without knowing of ~ ~-its presence.
The foregoing description of our invention is necessarily 25 of a detailed nature so that a specific embodiment of it might .
be set forth as required, but it is to be understood that :: : ~ .- .~ : -;. .
various modifications of detail, rearrangement and multiplication of p2rts might be resorted to without departing from its spirit, essence or scope.

. .
~30 ,, :~
: ~' `:

Claims (15)

1. A troll fishing downrigger, having fish attracting means and a leveraged line clamp that releasably attaches a fishing line, comprising in combination:
an elongate body having a streamlined shape for low drag motion in water, and means for attachment of a downrigger line in its upper portion;
a vertical stabilizing fin carried by the body and defining a medial propeller void and propeller connecting means;
a propeller having means for rotatably interconnecting with the propeller connecting means of the stabilizing fin to mount the propeller for rotary motion in the propeller void; and a line clamp, carried by the upper portion of the stabilizing fin, having forward and rearward spaced clamp arms extending a spaced distance upwardly from the stabilizing fin to form clamping surfaces therebetween in their upper portions, means to adjustably bias the clamp arms toward each other, and an elongate line arm extending a spaced distance upwardly from the rearward clamp arm with means for releasably fastening a fishing line in the upper end portion of the line arm.

2. The apparatus of Claim 1 further characterized by the surface of the stabilizing fin having means to reflect light impinging thereon.

3. The apparatus of Claim 1 further characterized by the surfaces of the propeller having means to reflect light impinging thereon.

4. The apparatus of Claim 1 further characterized by the surface of the stabilizing fin and propeller being selectively colored.

5. The apparatus of Claim 1 further characterized by the line arm being releasably carried by the rearward clamp arm to allow interchangeability of line arms.

6. The apparatus of Claim 1 further characterized by a fishing line having a fishing lure in its end portion carried between the adjacent clamping surfaces of the line clamp spacedly inward of the lure, with the lure end of the fishing line passing from the clamping surfaces and being releasably carried in the line fastening means of the line arm.

7. In a downrigger for troll fishing, having a weighted body with means for attachment of a downrigger line in its upper portion, the improvement comprising:
a vertically oriented stabilizer fin releasably carried by the downrigger body to extend therefrom to stabilize motion of the downrigger body through water, said stabilizing fin defining a medial propeller void and having means for rotatably mounting a propeller in the propeller void, and a propeller carried in the propeller void defined by the stabilizing fin for rotary motion responsive to motion of the downrigger through water.

8. The apparatus of Claim 7 further characterized by:
the propeller comprising two propeller blades each having paired opposed outer vein elements interconnected by medial web structure to a central shaft having bearing cups at each end, and the fin defining spaced opposed journaling shafts to engage the said bearing cups to mount the propeller for rotary motion.

9. The apparatus of Claim 7 further characterized by surfaces of the stabilizing fin and propeller having means to reflect light impinging thereon.

10. The apparatus of Claim 7 further characterized by the upper portion of the stabilizing fin carrying a jaw type clamp having two spaced clamp arms structurally joined in their lower portions to the stabilizing fin in forward and rearward relationship and extending upwardly therefrom, said clamp arms forming adjacent clamping surfaces in their outer portions, and a line arm extending a spaced distance upwardly from the rearward clamp arm, said line arm having means in its outer portion to releasably attach a fishing line.

11. The apparatus of Claim 10 further characterized by the clamp arms having means for adjustably regulating the clamping force between the clamping surfaces of said clamp arms.

12. The apparatus of Claim 10 further characterized by the line arm being releasably carried by the rearward clamp arm to allow selective interchangeability of line arms of different lengths.

13. In a downrigger for troll fishing, having a weighted body with a forward and a rearward portion and supported beneath a boat by a down rigger line supported on the associated boat, the improvement comprising, in combination, a releasable fishing line clamp carried by the downrigger and having two spaced cooperating clamp arms extending outwardly a spaced distance from support on the downrigger, in a forward and rearward relationship, to form adjacent clamping surfaces in their outer end portions to releasably clamp a portion of a fishing line therebetween, and a line arm extending a spaced distance outwardly from the rearward clamp arm, said line arm having means in its outer portion to releasably attach a fishing line to magnify forces on the fishing line carried by the said releasable attachment means required to release a fishing line portion clamped between the clamping surfaces of the clamp arms.

14. The apparatus of Claim 13 further characterized by the clamp arms having leans for adjustably regulating the clamping force between the clamping surfaces of said clamp arms.

15. The apparatus of Claim 13 further characterized by the line arm being releasably carried by the rearward clamp arm to allow selective interchangeability of line arms of different lengths.