Livewell apparatus and method

An improved livewell apparatus and method of operation thereof for use in recreational fishing boats and like watercraft wherein water from the livewell is withdrawn, conveyed through a heat exchange conduit in an auxiliary ice chest or other heat exchange arrangement, and returned to the livewell tank through an aeration spray head. The water in the livewell tank is cooled in this manner to a temperature sufficiently reduced from the natural aquatic habitat of captured gamefish to induce a state of slowed metabolism of the gamefish and, in turn, to prolong their captive life in comparison with conventional livewells.

BACKGROUND OF THE INVENTION 
The present invention relates generally to apparatus and methods for the 
temporary captive storage of live gamefish and other similar aquatic 
animals. More particularly, the present invention relates to an improved 
livewell apparatus and method for use in a recreational fishing boat and 
similar watercraft. 
Over recent years, recreational and sport fishing has grown considerably in 
popularity as well as sophistication with the advent of more 
scientifically-designed fishing equipment and techniques. As part of this 
trend, various technical and design improvements in recreational fishing 
boats have evolved, one such improvement being the provision of an inboard 
water reservoir or tank, commonly referred to as a "livewell," for 
containing a quantity of water in which to store captured fish to maintain 
them alive for a reasonable period of time in captivity. With the 
proliferation in past years of tournament fishing events with relatively 
sizable monetary awards to winning participants, the provision and 
reliability of a livewell in a fishing boat is of considerable importance 
to the serious fisherman in that typical tournament fishing rules provide 
for some penalization as to dead fish and, moreover, a fish normally loses 
several ounces of weight upon its death as a result of the natural 
emptying of the fish's waste cavities, scale loss and similar reasons. 
Conventional livewells provided in modern recreational fishing boats 
typically provide a battery-operated electric water pump for selectively 
filling the tank with water from the ambient body of water in which the 
boat is being operated and an overflow discharge line to establish a 
maximum level of water in the tank to prevent overfilling thereof. More 
sophisticated livewells also provide a pump-operated aeration system for 
withdrawing water contained in the tank and spraying it in return into the 
tank to replenish any oxygen from the water consumed by fish stored 
therein. An electric timing device may be provided to periodically actuate 
and de-actuate the aeration system. In addition, it is normally necessary 
in practice to periodically operate the fill pump for the tank to 
discharge through the overflow line fish scales, slime secretions and 
waste discharges which captured fish typically expel in their normally 
excited state after being placed in the livewell. a timing device may 
therefore also be provided in conjunction with the livewell fill pump to 
automatically perform this overflow dischage periodically. 
Despite the above-described provisions in the most sophisticated 
conventional livewells for maintaining a relatively clean body of 
contained water in the livewell and for continuously aerating the water, 
experience has shown that even the most sophisticated livewells are 
incapable of reliably maintaining captured fish alive for more than one to 
three hours. The severity of this problem can be affected by numerous 
factors, including the particular species of fish involved, the condition 
and excited nature of the fish, the condition of the water utilized in the 
livewell including for instance its oxygen content and temperature, etc., 
all of which make it difficult to evaluate and determine the reason or 
reasons for this problem. 
SUMMARY OF THE INVENTION 
Accordingly, it is a principal object of the present invention to provide 
an improved livewell apparatus and method capable of reliably maintaining 
captured fish alive for relatively extended temporary periods of time, 
such as up to twelve to sixteen hours covering an extended day's fishing 
trip. 
It is theorized that one of the principal causes of problems in maintaining 
captured fish alive is the excited nature of the fish when placed in a 
generally enclosed livewell or similar tank. As mentioned above, in this 
excited condition, fish tend to lose some portion of their scales and 
their natural slime secretions as well as to discharge bodily wastes and 
even to vomit the contents of their digestive tracts. All of this foreign 
matter in the water in a livewell poses a danger tothe fish in that the 
foreign matter may become lodged in the fish's gills during normal 
breathing. Moreover, the excited nature of the fish significantly 
increases its metabolism causing it to utilize oxygen from the water at a 
significantly increased rate. Finally, it is known that fish are 
relatively sensitive to the temperature of the ambient body of water and, 
therefore, any difference in the temperature of the water in the livewell 
from that of the surrounding ambient body of water, particularly when the 
livewell water is elevated, may exacerbate the excited condition of the 
fish. Conventional livewells make essentially no provision for 
compensating for any of these factors, other than the aforedescribed 
provision of water overflow and refilling of the livewell and an aeration 
system for replenishing oxygen to the water contained in the livewell. 
In substantial contrast, the present invention provides a novel livewell 
apparatus and method designed to operate according to the fundamental 
concept of cooling the water contained in the livewell tank to a 
temperature sufficently reduced from the natural aquatic habitat of 
captured gamefish to be stored in the tank to induce a state of slowed 
metabolism of the gamefish. In this manner, the captive life of the fish 
is prolonged by effectively calming any excited tendency of the fish to 
reduce or even eliminate the above-described waste discharges and other 
foreign matter in the livewell while at the same time the cooler water is 
capable of retaining a greater quantity of available oxygen for the fish. 
In the preferred embodiment of the present method and apparatus, a heat 
exchanger, preferably an auxiliary tank for containing a quantity of ice, 
is provided in conjunction with a circulating pump and conduit arrangement 
for withdrawing water from the livewell tank and transporting the 
withdrawn water through the heat exchanger to cool the water. A spray 
arrangement is associated with the circulation system for returning the 
cooled water into the tank to aerate the water. 
Preferbly, the heat exchanger is arranged to circulate withdrawn water 
therethrough along an at least partially upward circulation path through 
the auxiliary ice tank to enchance heat transfer from the withdrawn water. 
A control arrangement is also provided with an adequate timing device for 
selectively controlling the actuation and de-actuation of the circulating 
pump at predetermined intervals for regulating the temperature of the 
water contained in the tank. The circulation system also includes a 
secondary bypass conduit for bypassing the heat exchanger, with a valve 
being associated with the bypass conduit for selectively opening and 
closing it to water circulating operation. A sensing device is providd for 
monitoring the temperature of the water contained in the livewell tank, 
the control arrangement being operatively associated with the sensing 
device and with the bypass valve for controlling the opening and closing 
operation of the valve in relation to the sensing device to maintain the 
water in the tank at a predetermined desired temperature. Preferably, the 
apparatus and method of the present invention are operated to maintain the 
water temperature in the livewell tank at a reduced temperature in the 
range of approximately 20-25 degrees Fahrenheit below the natural aquatic 
habitat of the captured gamefish, but not lower than approximately 45 
degrees Fahrenheit.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIG. 1 of the accompanying drawings an improved livewell 
apparatus according to the preferred embodiment of the present invention 
is shown mounted within the hull of a conventional fishing-type 
recreational boat of the typical false-bottom type. Such boats include an 
outer hull 22 and an interior false bottom or deck 1 horizontally mounted 
within the hull at a spacing above the bottom thereof. Conventionally, 
fishing boats of this type have an insulated tank 41, commonly referred to 
as a "livewell," mounted beneath the boat deck 1 and accessible 
therethrough by a movable cover or lid 2 the interiorly-facing surface of 
which is also insulatd at 3. An auxiliary insulated storage compartment 9 
is also mounted beneath the deck 1 adjacent the livewell tank 41 with a 
respective movable lid or cover 12 interiorly insulated at 13 providing 
access to the compartment 9. Typically, the storage compartment 9 is 
intended for use in storing refreshment and food items such as canned or 
bottled drinks, sandwiches and the like. A drain plug 16 is provided in 
the bottom of the compartment 9 for draining any water or the like that 
may collect in the compartment 9. 
A conventional water pump 18 is mounted within the false bottom area of the 
boat hull 22 and communicates through an inlet conduit 42 with an inlet 
opening 19 in the boat hull 22, usually formed in its aft transom, and 
communicates through an oulet conduit 43 with the interior of the livewell 
tank 41 for pumping a quantity of water 6 into the livewell tank 41 from 
the ambient body of water in which the boat is being operated, thereby for 
filling the livewell tank 41 to a desired level. The pump 18 is 
operatively connected with a suitable electrical power supply 
representatively indicated at 29, such as the engine battery of 
conventional fishing boats, with an appropriate manually-operated switch 
20 being provided for selectively actuating and de-actuating the fill pump 
18. An overflow conduit 17 communicates with the interior of the livewell 
tank 41 in the upper region thereof and extends therefrom to and through 
the boat transom 22 for discharging water from the livewell tank 41 to 
prevent overfilling thereof above the level of the overflow conduit 17. 
A circulating water pump 8 communicates through a filter 7 with the 
interior of the livewell tank 41 at the bottom thereof and an aeration 
spray head 4 is mounted within the livewell tank 41 above the level of the 
overflow conduit 17, the outlet of the pump 8 conventionally being 
connected through a suitable conduit directly with the spray head 4 for 
purposes of aerated circulation of the water contained inthe livewell tank 
41. A discharge conduit 15 communicates with the spray head 4 through a 
two-way valve 5 and extends therefrom through the boat transom 22 for 
selectively diverting water circulated by the pump 8 to drain the livewell 
tank 41 when desired. A timer control device 21 is operatively connected 
with the circulating pump 8 for permitting manual and automatic timed 
regulation of the actuation and de-actuation of the circulating pump 8. 
The control device 21 includes an operating switch 27 having "off," 
"manual," and "automatic" settings and is connected with a suitable 
electrical power supply indicated at 30, such as the aforementioned motor 
battery of the boat. In the "manual" setting of the switch 27, the 
circulating pump 8 is operated continuously, while in the "automatic" 
setting the circulating pump 8 is operated intermittantly at periodic 
intervals between actuations as determined by an adjustable timing device 
set by a control dial 28. 
The fishing boat and livewell apparatus as thus far described are 
conventional. According to the present invention, the auxiliary storage 
compartment 9 is modified to function as a heat exchanger when filled with 
a quantity of ice, indicated at 11, and the circulating aeration system of 
the livewell apparatus is modified to circulate water withdrawn by the 
circulating pump 8 through the heat exchange arrangement of the auxiliary 
storage compartment 9 for purposes of cooling the water prior to its 
aerated return to the livewell tank 41. More specifically, the auxiliary 
storage compartment 9 is fitted interiorly with an extended length of PVC 
or other suitable tubing formed in a coil or other suitable heat transfer 
configuration to be in heat transfer contact with the ice contained in the 
storage compartment 9. The tubing conduit 10 rests in the bottom of the 
compartment 9 with the opposite ends of the conduit 10 extending 
vertically to adjacent the upper region of the compartment 9 and therefrom 
outwardly through the compartment 9, one end of the tubing conduit 10 
being connected through an insulated conduit 44 with the outlet of the 
circulating pump 8 and the other end of the tubing conduit 10 being 
connected through a similar insulated conduit 14 with the spray head 4. 
In operation, water withdrawn from the livewell tank 41 through the 
circulating pump 8 is diverted through the insulated conduit 44 into the 
heat exchange tubing 10 within the auxiliary storage compartment 9 and 
therefrom through the insulated conduit 14 to the spray head 4 for return 
to the livewell tank 41. The heat exchange conduit 10 is completely 
submerged within the quantity of ice 11 in substantially complete and 
continuous heat transfer contact therewith so that, as the water withdrawn 
from the livewell tank 41 is circulated through the heat exchange conduit 
10, the water is progressively cooled, the vertical exhaust leg 10' of 
the conduit 10 serving to enhance this heat transfer effect by presenting 
some resistance to upward water flow therethrough to improve the head 
pressure on the circulating pump 8 and to produce a degree of water 
backflow within the heat exchange conduit 10. In accordance with the 
present invention, the modified heat exchange circulation system above 
described is operated to cool the water in the livewell tank 41 to, and 
maintain the water at, a temperature sufficiently reduced from the natural 
aquatic habitat of the surrounding body of water in which the boat is 
being operated and from which gamefish are captured to induce a state of 
slowed metabolism of the gamefish. Optimally, it is believed that the 
water temperature in the livewell tank 41 should be reduced in the range 
of approximately 20-25 degrees Fahrenheit below the surface temperature of 
the surrounding body of water, but in no event to be less than 
approximately 45 degrees Fahrenheit. In this manner, the water temperature 
in the livewell tank 41 represents a sufficiently reduced temperature in 
relation to the surrounding body of water for the intended purposes of 
slowing the metabolism of stored fish without producing such a drastic 
temperature reduction as to possibly inflict a state of shock on the 
stored fish. In order to reach and maintain the desired temperature level, 
the operator may actuate and deactuate the circulating pump 8 manually 
through intermittent switching of the operating switch 27 between its 
"off" and "manual" settings. Alternatively, the operator may set the 
operating switch 27 in its "automatic" mode and appropriately adjust the 
timing device through its control dial 28 to obtain a regular periodic 
actuation and de-actuation of the circulating pump 8 at a selected 
interval sufficient to maintain the water temperture in the livewell tank 
41 within the aforementioned range. 
This improved cooling circulation system has been found to provide 
remarkably improved results over conventional livewell systems in 
substantially prolonging the captive life of gamefish stored in the 
livewell tank 41. In contrast to conventional livewell systems wherein 
gamefish can be typically kept alive for only one to three hours, the 
livewell apparatus and its method of operation according to the present 
invention have been found to reliably maintain captured fish alive for up 
to twelve to sixteen hours. While the precise reasons for this significant 
improvement have not been scientifically determined, it is believed that 
the marked reduction in water temperature in the livewell tank 41 in 
relation to the natural habitat of captured fish serves to slow the 
metabolism of fish and thereby induce a state of near dormancy of captured 
fish almost immediately following their placement into the livewell tank 
41, much like the change in fish metabolism and activity known to occur in 
the winter months. As a result, the cooler water temperature essentially 
tranquilizes the fish to either dull or soothe any tendency to excitment 
and, in turn, the fish are relatively inactive while in the livewell tank 
41 so that they experience only minimal scale and slime loss and minimal 
waste discharge and vomiting. In addition, the cooler water is more 
capable of holding a greater quantity of available oxygen for the fish 
while at the same time the slower metabolism of the fish causes them to 
utilize the available oxygen at a slower rate, the aeration of the water 
produced by the spray head 4 being more than sufficient to replenish the 
oxygen consumed by the fish. Accordingly, as a net result, captured fish 
are considerably less likely to die while stored in the livewell tank 41 
in contrast to storage in a conventional livewell tank and, therefore, the 
captive life of the fish is substantially prolonged. As an added 
advantage, the resultant reduction by the present invention in the scale, 
slime and waste discharges by the fish in the livewell tank 41 serves to 
maintain the water therein considerably cleaner and freer of debris than 
in conventional livewells so that less occasional water overflowing and 
refilling of the livewell tank 41 is necessary to remove such foreign 
matter and, in turn, the efficiency of the cooling system is enhanced. 
Referring now to FIG. 2, a modified embodiment of the improved livewell 
apparatus of FIG. 1 is shown, with like reference numerals being applied 
to the corresponding components of FIG. 1 described above. Basically, the 
livewell apparatus of FIG. 2 differs from that of FIG. 1, first, in the 
provision of an annular jacket formed interiorly about the walls of the 
auxiliary storage compartment 9 as the heat exchange conduit 10 and, 
second, in the provision of an insulated bypass conduit 25 communicating 
between the inlet and outlet conduits 44,14 to the heat exchange jacket 10 
with a thermostatically and manually controllable solenoid valve 24 
positioned at the juncture between the inlet conduit 44 and the bypass 
conduit 25 for controlling the direction of circulation of water withdrawn 
by the circulating pump 8 from the livewell tank 41. 
The control of the solenoid valve 24 is provided by a control module 40 
operatively connected through a switch line 31 with the circulation pump 
control device 21 to be enabled for operation of the valve 24 whenever the 
operating switch 27 for the circulating pump 8 is in either its "manual" 
or "automatic" mode. The control module 40 is also operatively connected 
with a temperature sensing device 23 mounted interiorly within the 
livewell tank 41 to monitor the temperature of the water 6 contained in 
the livewell tank 41 and to display the prevailing temperature on a 
digital liquid crystal display 34 operated by a respective electrical 
power source indicated at 32, such as the boat motor battery, through a 
respective on-off operation switch 33. The control module 40 also includes 
a conventional thermostat operated by a control switch 35 for setting a 
predetermined desired "set point" temperature for the water in the 
livewell tank 41 through a manually-settable calibrated temperature dial 
36. The operating switch 35 for the thermostat is provided with "off," 
"manual," and "automatic" settings. In the "off" mode of the switch 35, 
the solenoid valve 24 remains in a normal open operating position for 
permitting circulating water flow through the inlet conduit 44 into and 
through the heat exchange jacket 10 while preventing diverted waterflow 
through the bypass conduit 25. On the other hand, in the "manual" mode of 
the thermostat switch 35, the solenoid valve 24 is actuated to a bypass 
position to close the downstream section of the inlet conduit 44 while 
opening the bypass conduit 25 to divert circulated water withdrawn by the 
pump 8 from the livewell tank 41 through the bypass conduit 25 to thereby 
bypass the heat exchange jacket 10. In the "automatic" mode of the 
thermostat switch 35, the operation of the solenoid valve 24 between its 
normally open and bypass positions is carried out automatically in 
relation to the sensed temperature of the water in the livewell tank 41 
detected by the temperature sensor 23 and the set point temperature 
established by the position of the dial 36 to position the solenoid valve 
24 in its normally open position when ever the detected temperature in the 
livewell tank 41 is greater than the set point temperature determined by 
the dial 36 while actuating the solenoid valve 24 to its bypass position 
whenever the detected water temperature in the livewell tank 41 is less 
than the set point temperature designated by the dial 36. As an added 
feature of the control module 40, a digital liquid crystal display 39 is 
provided in operative association with a temperature sensor 26 mounted on 
the boat transom 22 for operation by a suitable electrical power source 
indicated at 37, such as the boat motor battery, through an actuating 
on-off switch 38 for displaying the surface temperature of the surrounding 
body of water in which the boat is being operated. 
As will be understood, the control modules 21,40 of the livewell apparatus 
of FIG. 2 provide enhanced preciseness in the control of the aeration and 
water temperature of the livewell tank 41. Through the use of the surface 
water temperature display 39, the operator can precisely adjust the dial 
36 to establish the precise desired set point temperature for the water in 
the livewell tank 41 in accordance with the aforedescribed optimum 
temperature parameters established by the present invention. In the 
"automatic" modes of the circulation pump switch 27 and the thermostat 
switch 35, the circulation pump 8 will be actuated at desired intervals to 
maintain sufficient water circulation for proper cooling and aeration of 
the water in the livewell tank 41 while, at the same time, the thermostat 
of the control module 40 continuously actuates the solenoid valve 24 
between its normal and bypass positions to control the circulation of the 
water either through the heat exchange jacket 10 or through the bypass 
conduit 25 to closely regulate and maintain the temperature of the water 6 
in the livewell tank 41 at the set point temperature determined by the 
dial 36. The temperature display 34 enables the operator to check the 
proper operation of the system by comparing the prevailing sensed 
temperature of the water in the livewell tank 41 with the set point 
temperature determined by the dial 36. Alternatively, either or both of 
the circulation pump 8 and the solenoid valve 24 may be manually 
controlled through their respective control switches 27,35. 
It will therefore be readily understood by those persons skilled in the art 
that the present invention is susceptible of a broad utility and 
application. Many embodiments and adaptations of the present invention 
other than those herein described, as well as many variations, 
modifications and equivalent arrangements will be apparent from or 
reasonably suggested by the present invention and the foregoing 
description thereof, without departing from the substance or scope of the 
present invention. For example, it is contemplated that other forms of 
heat exchangers and other means of cooling the water in the livewell tank, 
e.g. thermonic chips, a refrigeration unit, etc., may be utilized 
consistently with the present invention instead of the provision of a 
quantity of ice in an auxiliary storage compartment. Accordingly, while 
the present invention has been described herein in detail in relation to 
its preferred embodiment, it is to be understood that this disclosure is 
only illustrative and exemplary of the present invention and is made 
merely for purposes of providing a full and enabling disclosure of the 
invention. The foregoing disclosure is not intended or to be construed to 
limit the present invention or otherwise to exclude any such other 
embodiment, adaptations, variations, modifications and equivalent 
arrangements,the present invention being limited only by the claims 
appended hereto and the equivalents thereof.