Venturi for livewells

Guys,

I've been looking over the various designs and livewells projects here and theres some great work bye you guys, which helps others plan theirs, so thanks heaps in advance.

Something I have seen in my travells, over the years, is pro lobster fishers keeping crays alive in pretty warm water and warm air temp conditions out at the Abrolhos islands in plastic tubs on deck with water circulating systems.

Basically these are just the same as your own livewells.

However...one thing these guys do, which as yet I haven't seen done in any livewells, is aerate their water via venturi pipe (the bernouli effect) on the inlet water. (Just like a compressed air spray gun "sucks fluid up the pipe from the paint pot, just in reverse, this one sucks air downward thru the straw pipe and mixes it with the water!).

Where the plumbing pipe from the bilge pump is supplying water to the bottom of the livewell, they install a small straw like plastic tube into the top of the pipe (bottom cut on a 45 degree which protrues inside the pipe) - and it stands fixed to the side of the tub (read livewell) so that the top is just a little ( 1 inch)higher than the livewell level.

As the waters pumped thru the pipe bye the bilge pump, it sucks in air thru the strawlike tube - therebye aerating the water as it enters the tub (livewell).

This obviates the need for "pinhole sprays of water jet" etc around the top of the well via additional plumbing as well as obviating the need for 12v aquarium pumps & aerator stones and so on which only help to deplete your electrical supply quicker.

It's easy cheap and effective - hope it helps some.

Another thing to consider, with your livewells is that it's probably not a BAD idea, to have the drain outlet at the BOTTOM of the well - (at the opposite end to the now venturi fitted inlet), as this helps to "extract" the nitrates (read bream crap/shyte) that bream can excrete when under stress in a livewell environment....since it settles to the bottom!.

Should you elect to install a thru hull fitting below waterline in your hull for the inlet or outlet of your well - rather than pumping it both in and out over the transom, or out thru the hull above waterline - I strongly suggest that all such thru hulls below waterline should be fitted with a brass or stainless seacock, so that in the event of a hose failure - you can turn the sea DohDohDohDoh off to stop the boat sinking!

Again if you have ANY below waterline thru hulls, the hoses should be connected to the seacocks (which are fitted direct to the thru hull) with TWO stainless 316 hose clamps (not one!).

As a last resort - carry a few round tapered wooden dowels that can be hammered into a broken thru hull in the event one does break - at the thru hull / seacock joint...

Lastly - if you elect to install any thru hulls below waterline try and avoid like the plague the white plastic variety which have a habit of going brittle after a couple years and breaking.

The white plastic type are OK above waterline if you wish to save a few bucks...below water try and use either bronze or 316 stainless for those of you with alloy hulls.

One more thing - if your installing / building a livewell is to consider avoiding "square" corners, and acute angle corners (like you get with a diagonal seperator). While these might be OK for bream - often if you wan't to use that well as a livewell for small bait, they will swim up into the corner, get stuck there and die. Small baifish like that need to keep their head into the current, (to keep waterflow over the gills) so you want round (coved) corners in your well and a good water flow rate (like a 500 gph bilge pump).

Be sure to add a strainer to the outlet so baitfish, scales and other crap don't get sucked into it and block it ( leaving the inlet pump flooding your boat!).

Another "trick" worth considering (and I don't know the bream tournament rules on this - so maybe someone can comment) - IF you get a highly strung out fish (and it mightn't be a bream - lets say you have a trout - mulloway or some other species, even saltwater, that just won't settle in the livewell and is doing itself harm as well as the other fish therein)....you can quieten them all considerably with the judicious application of just ONE drop of clove oil from a small bottle with an eye dropper.

Clove oil is something you should be able to get from a pharmacist for toothache, it's a natural substance thats a great local anaesthetic (for a toothache) or for fish in a confined water volume situation like a livewell. (No using it to stun wildfish in waterholes - thats illegal).

As soon as you replace the water or release the fish into clean new water, they will recover very very quickly...

Like I said, only to be used where absolutely necessary and better check rules first - maybe it's not needed with bream (and I doubt it is, as they don't seem to be a very excitable species).

One last one is for warm water / tropics use, (or VERY hot summer days / heatwave type 40*C plus on the Swan) where water holds little dissolved oxygen, is to have a very small Oxy bottle from a oxy viva type setup - connected to an aerator stone via a low pressure adjustable regulator and allow a small tricke of pure oxygen into the water - that will stop any fish dieing on you. Of course compressed Oxygen needs to be treated with extreme care especially in case of a fire (you all carry fire extinguishers onboard?)

Air is only about a third (from memory) oxygen, and warnm water doesnt hold a LOT of dissolved oxygen at the best of times, aerating warm water doesn't actually raise the oxygen level very much..whereas pure oxygen does elvate it a great deal bye comparison making it much easier for the fish to breath thru their gills.

Hope this gives some food for thought for those designing / building new bream / bass boats and livewells etc..

Cheers!

[Geoff R]

Seriously you always are full of relevent info Trouty, top marks, however i got lost I don't spose you can post some pics or a drawing or something:confused:
Regards Geoff

[Geoff R]

Look at the pictures:o
I may not be very smart, but i "used" to be able to lift heavy things;)
Geoff

[Mick]

The "Keep Alive" brand of aerator uses the concept that you describe, they have a plastic tube with a valve on the end so you can adjust the flow of air and thus the size of the bubbles delivered. They are used by a heap of guys over here on the east coast.

[Geoff R]

But lets say for instance you catch a fish in fresh or brackish water and then travel to the weigh-in in salt, you let go a fish who may not be ready for the sudden change to salt.
I like a system that constantly turns water over so you don't have to worry about stuff like that, or can you incorparate both?

[jimi]

Geoff, I think this explains what trouty is on about

[Geoff R]

I think i get the idea now, so the water pumping through the pipe creates a vacuum from which air sucks down and mixes with the water. I might include this system in my next refit, what sort of tube dimension are we looking at and how do you insert it

[Bear]

No offence guys, but if you have a system that replaces the water, why then add extra as an aerator. The reason I have mine set up the way they are is that the turn over of water replenishes any oxygen loss and exposes the fish to the different water types.

I would have thought the less gear the better. If you are stuck with a system where filling or replacing the water is harder, then you will have to oxygenate of course.

JMO.

[Geoff R]

I just figures out how to do it myself, retic spray fittings would screw into the inflow pipe

[Geoff R]

Creating the best possible chance of releasing a fish in it's best condition possible.

[jimi]

Bear, I guess it depends on how often you run your pumps to replace the water. Maximising the amount of air in the water can only be a good thing if the pumps are spending some time turned off.

This system is about as simple as it gets. Lots of guys use the spray bars, but they can get clogged easily from any crap in the water. This system is much harder to clogg.

Geoff, those 4mm risers than you can get for retic systems would probably do the job well. Good thinking.

cheers
James

[Bear]

One of the reasons I did my live wells the y they are was after a chat with a guy I know in the East. One of the things talked about was stressing the fish. One thing brought up was that things like spray bars actually make a lot of noise and can cause a lot of water movement.

His concern was that he had no way to know how much that may have actually stressed the fish. I agree the aerator stone idea is a lot less agressive and wonder if one of the aerator bars you can get with fish tanks would suit more for the size of wells we use.

[Geoff R]

I remember scooping hordes of DohDohDohDoh out the bottom of my wells, after the fish was released, this system would prevent sediment on the bottom of the tank and totally turn the water over

[jimi]

Geoff, I'm not sure if that is good or not. If all that crap is blown around the tank it may end up getting into the fishes gills and eyes etc. and doing some damage. Might have to move the inlet slightly off the bottom to avoid that.

[Geoff R]

I wish Trouty was on he'd know exactly how to square this away

I took someone heres advice and was just finnishing off the curly marri dining table I've been building these last 3 weeks or so...
You know how it is - gotta pay the bills comming up to June 30 & all.

Thanks Jimi,

Thats exactly what i was on about...I'd be easier to understand if you could see me wavin my arms as i speak! :p

The only "difference" is - the thin tube doesn't have to be inside the livewell as depicted by Jimi - it CAN be outside the livewell - just before the inlet and strapped up to the outside of the livewell..but it sure will work inside just as well.

Yes - it should be a "open system" in that it constantly replaces the water in the livewell bye pumping fresh in and cold water out.

I think Bear asked a good question tho - why bother with "extra aeration" if your constantly replacing the water anyway?

There is an answer - but as usuall with me it'll be the full book version.

Water, particularly in summer when it's hot and flow levels are low - tends to stratify into usually 3 distinct bands.

The top few feet - during a really hot day (heat wave week) - and when the winds not blowing it hard, is usually warmest. If you ever jump in the river for a swim - you'll notice this - about 2 - 3 ft down it gets colder, quite often quite a bit colder so you'll know what I mean.

That top warm layer has next to no oxygen in it. Tropical species like the lady springer fish (giant herring) which occasionally visit the Swan and some other rivers in summer, have specially adapted gills and can live quite well in warm water / low dissolved oxygen content water - due to their specialised adaptation.

Coldwater species like trout and bream etc can't - they need cold high oxy water...this is why they are the first to succumb when algal blooms rob the water of dissolved oxygen...

Anyway, the middle layer thats colder than the top often has the most dissolved Oxy and often times you'll find a lot of riverine species in this layer. (Sometimes you'll see the temperature inversions on your sounder much like you might also see the salt / freshwater wedge effect but thats another story).

The very bottom layer is usually bloody cold - almost frrezing - try duck diving to the bottom of the river in a deep hole like Blackwall reach - you'll find the really cold stufff it'll make your head ache often...it's so cold.

Very often these deep holes are spring fed from underneath ( i.e. they go down into the water table). Usually they are very oxygen depleted and yet some species still manage to get bye down there...(crabs & prawns, mulloway).

So - the top layers got little dissolved Oxy and so's the very bottom layer...

When your boats cruising along - your taking your livewell water from the warm top oxygen depleted layyer of water - the fish MAY have come from the oxygen richer middle colder layer...anmd already be hypoxic (low blood oxygen levels) from the fight - and due to the fact they have to fight the last crucial minutes near the boat in the warm upper low oxygen layer near the surface.

This is the reason why it's not a bad idea to add the extra oxy Bear via venturi aeration to the livewell water - pure oxygen would be MUCH better but of courseit would "cost" $ in terms of a CIG refill all the time to do this.

When you see aquaculturists send cold water fish (like trout) fingerlings long distances for farmers etc, they bag them up inside 2 tuff plastic bags and squeeze all the air out of the top of the bags - then they "inflate" the tops of the bags with pure oxygen from a high pressure cyclinder before tieing them off tight with elastic bands and string etc and packing them in a cardboard box.

This will keep up to a couple thousand trout fngerlings alive in the water for up to 18 hours...due to the oxygen rich environment.

We can learn a lot from this sort of technology - in as far as providing the very best livewell environment for our fish.

Some guys I've seen use "live bait hotels" to keep bait alive in their docks / marina slips for the next days fishing. These are the equivalent of a plastic 44 gallon (55 gals in the USA) drum with Lots of small holes drilled in em (thousands and thousands of holes, so the drum almost becomes a collander...think wigfes plastic spaghetti strainer).

They weight the bottom and have a screw on drum lid like in a brewing kit & tie a rope to it, and sink it in their marina slip in some current..

Next morning empty contents into livewell and go fishing.

In many respects, it would be better for captured bream to be kept during the duration of a comp, in a live fish hotel sunk below the boat while slow moving on the electric, and just transfer them to the livewell for the trip to the weigh in...and for that short duration ride provide them with pure bottled oxygen in the livewell IMHO.

I'm talking here about tactics to reduce stress on the fish in HOT weather, heat waves, warm water etc...you likely already get away admirably with livewell systems that already are in use in mild weather when these considerations mightn't be necessary.

Another consideration...tho - is a 12 V eutectic unit for your livewell - to actually cool the incomming water...thru a refrigerated eutectic coil arrangement...before it enters the livewell past the venturi...

You could knock up one of these easy enough out of the old 12Volt car fridge eutectic esky units (or a full 12 v engel car fridge / freezer if your particularly flush with cash!). Make up a square "coil" of half inch black poly retic pipe, using short sections of the pipe and the plastic 90 degree elbows, that fits inside the cooler fridge, and wraps continously from top to bottom..on all four sides leaving the middle square area inside clear to hold your drinks for the day! ;)

Plumb your livewell water to go thru this "heat exchanger coil" inside the 12 V cooler before it enters the livewell past the aeration venturi pipe.

Fill the eutectic cooler esky with water, and set the thermostat to coldest setting. Stick your cold cans in the area inside the heat exchanger coil - you can even make this a ice and water slurry at the start of the day if you like, the eutectic will help to keep it cold all day.

The water being pumped to the livewell thru this black plastic pipe heat exchanger will be cooled bye passing thru the coil sumbmerged in the cold water containing your drinks, before it enters the livewell.

If you want to get cunning as far as fish comfort levels go, get yourselves a small battery operated remote temperature probe thermometer....they aren't dear about 10 or 15 bucks from memory.

Mark the wire that connects the digital temp readout to the probe, in 1 foot increments with a waterproof texta or bands of plastic coloured insulation tape wrapped around it (if you use your sounder in feet mode rather than meters mode).

When you spot your first bream/(school of bream if your lucky) for the day - on the sounder, make a mental note of the depth they are at. Then stop and lower your remote temp probe down to that same depth, and make a note of the water temperature.

Ok - now you know what water temp your going to be pulling you fish from and what temp to aim for in your livewell..

Pop the probe in the livewell..., with the readout somewhere you can see it easily all day...

On your plumbing of your livwell have a tap handy that you can "regulate"the flow rate of water thru the heat exchanger and into the livewell. Keep an eye on the temp readout in the livewell and vary the rate of water flow thru the heat exchanger into the livewell so that the temp remains the same as the water at the depth you saw the fish at...

This way - the fish are in water thats the same temp they were just caught from - with additional oxygen from the venturi pipe setup...they should be happy campers.

Not only that - you got nice cold drinks all day into the bargain..

Fish hotels, heat exchangers, what next?..

Oh yeah, heres a thought too - if your going to drain the livewell from the bottom as suggested to discharge the nitrates from the bottom of the livewell....and your going to regulate the inlet water to get the temperature in the livewell "just right" for the fish, then - you will of course need to regulate the drain out water via a similar tap so as not to drain the livewell down during the course of the day with differential inlet supply and outlet drainage rates!

To monitor this water level visually at a glance over the course of a day - you need a water level gauge for your livewell of course so yourt not opening and closing the darn thing all day (and letting light in scaring the fish).

A clear plastic pipe fixed up the outside of the livewell, (alongside the ventur tube?) ;) and plumbed into the bottom of the livewell - will of course fill to the level of the water inside, and the level can be seen at a glance.

Hope this helps - i'm not very good at drawing things in paintshop - maybe Jimi would be good enough to sketch this out again to make it simple to understand for everyone?

Cheers!

[sam]

Hey there trouty,
reading your gear is like coming out of my lectures back at uni studying Aquaculture. What's your background?
Sam

Jack of all trades, master of none - vaccinated at birth with a grammaphone needle!

I had a go at a drawing - lets see if it'll upload - probably too darn large :mad:

Might be easier to read at this link maybe?

http://tht.sunfx.net/trouty/Aerated%20water1.jpg

If not then I bloody give up!:rolleyes:

Cheers!

[JellyBobr]

For the drain you could use a technique that I think is called a "stand pipe".
A reasonably large pipe is stood vertical and cut off at the required water height. This vent straight out the bottom.
A second larger pipe is then fitted around the first pipe. It is located just off the bottom of the tank and extends above the height of the drain pipe but lower than the overfow height of the tank.
In operation this removes the rubbish from the bottom of the tank by the water flowing out. The outside pipe while acting as a course filter for those fish or bait also acts as a safety by pass so that a blockage is bypassed. Saves flooding the boat.
I would also introduce the water from the top above the water line. Two reasons 1. a leak wont empty the tank 2. If the pump stops there is no chance of a syphoning effect from the bottom of the tank.

2. If the pump stops there is no chance of a syphoning effect from the bottom of the tank

I figured with my comments about thru hulls and bilge pumps etc, that I was "stating the obvious" but this shows that when it comes to sinking boats - you can never assume anything! :D

All bilge pumps to thru hulls should of course - have a riser loop in them - to prevent back siphoning when the pumps not operating!

Probably the literature with the bilge pump points this out - if not then it should...

Cheers!

For any of you who use Rule bilge / livewell aerator pumps....

Theres a product safety recall out from Rule industries - your pump could sink your boat...if a couple screws come loose.

details here (http://www.rule-industries.com/livewell.asp)

Cheers

hey Guys,
Just thought i'd add a couple of points to the discussion.
Firstly... Trouty they are very good ideas! But to be honest i dont think one should bother with the Oxygen Syphon tube.
I have been involved in Aquriums and the like since i was 10 (I am actually missing my lil finger from my right hand due to an electrical incident with an Aquarium), anyways, When aerating a tank (livewell, aquarium, etc) the extra bubbles from your air stone or whatever actually make almost no difference to the Oxygen saturation of the Water. The oxygen in the Water is almost entirely from water to air contact, ie)The top layer of water where it comes into contact with the Air.
The more tubulence you make on the surface of your tank, the more oxygen that will be generated in the water. Therefore, the best way to add more oxygen to the water is by having a spraybar or something to pour water on to the surface and thus create more turbulence.
The air stones which make bubbles are really a gimmick. They have very little effect. Adding the vaccum tube will not really add more oxygen to the water before it enters the tank.
HTH

Dave

Also Geoff and others interested...
It actually takes a few days for the effect of a water shock (change in conditions) to be felt on fish. By simply changing water in your tanks while your changing areas (and therefore salinity levels, temps, etc) wont really help. If your goin to move fish from one area to another, your better off moving them the smallest amount possible. I do however think that in most rivers, the change in salinity over the distances your likely to cover in relocation, wont really matter.
HTH

Dave

I don't doubt the sincerity of your post for a second..however I find it's logic a little hard to follow.

Surface area interchange between the water and air is indeed where the oxygen is absorbed into the water...(we agree on that much, so far so good).

The surface area of your aquarium is indeed also where a lot of oxygen is absorbed into the water as it is with a livewell..
(again we agree, so far so good).

Where I got last was the bubbles being a gimmick.

Work out the surface area of a sphere compared to a flat plane...

The surface area of every bubble is a huge surface / air interchange area for the absorbtion of oxygen...multiplied bye a lot of bubbles = far more surface area for oxygen absorbtion than any flat surface layer of an aquarium or livewell will ever have...and it keeps going all the time - ie. it's replenish rate is many times higher than the meniscus (surface film) on the aquarium / livewell.

Don't get me wrong - surface jets are good too - and if you want MAXIMUM absorbtion and feel like doing the plumbing then hey - add jets too - no argument from me there.

As far as onboard oxygenated systems, this link should convince you that these systems are already in use in the USA for such things as baitwells and the pro bass circuit!

http://www.keepalive.net/oxygen/

http://www.keepalive.net/oxygen/baitbst.jpg

OXYFL02® BAIT BOOSTER
$595.00

The Bait Booster is the only low pressure oxygen system that can provide oxygen to your livewell and eliminate the use of high pressure oxygen cylinders.

The Bait Booster uses Pressure Swing Technology. It extracts oxygen from the atmosphere, concentrates the purity and generates almost pure oxygen! Built for continuous duty, the system draws about 7 amps at 12 vdc and comes with everything needed for operation.

Features and Benefits of the OxyFlO2® Bait Booster

No oxygen cylinders to fill and refill.
Continually produces up to .5 liters of oxygen per minute.
Eliminates the danger of high pressure cylinders on board.
Ideal for use with low pressure delivery systems such as KeepAlive or inexpensive diffusers.
Dimensions: 13 1/4"H X 13 1/4"W X 6 1/2"D

Warranty: 1 Year limited warranty against manufacturers defects. Warranty void if abused or submerged in water.

Of course another 12v appliance to drain your precious batterys...BUT it does avoid the need to carry high pressure oxygen cylinders aboard your boat (as well as the hassel of refilling them)..albeit cylinders are also availabe!

Oxygenated livewells isn't THAT much of a "new thing" it's just that we haven't seen a lot of it downunder yet is all...

Like most things American (think bass boats & tournaments) it's probably only a question of time...and for those of us "messing around" with the idea of a building a livewell, it's not a bad thing to have lots of info to start out with - theres nothing worse than building one and then wishing after you'd known about product A,B or C or idea 1, 2 or 3...when you see someone else with one and go ..

Homer Simpson Duh, ahh, why didn't I think of that???!!!

When too much info is never enough...

If anyone contemplates using an oxyfgenated livewell - please note that you also need to use an aeration system to REMOVE built up CO2 from your livewell water.

It's not so much the lack of Oxygen that can kill off fish in a livewell as it is the build up of CO2 (particularly in recirculating systems where the water isn't (exchanged).

carbon dioxide can often build up to levels which can be detrimental to fish health. If you are adding pure oxygen to your system, you are producing 1.4 times more CO2 than the amount of O2 you are adding and unless you are removing it somehow, you will run into big problems. Carbon dioxide levels above 20 mg/l will inhibit a fishes ability to utilize oxygen by 50% and it is possible for fish to suffocate even if the oxygen saturation level is adequate.

One of the ways to reduce CO2 buildup in the system is through aeration. This is simply exposing as much water to as much air as possible which in turn releases the CO2 into the air. This happens because the CO2 in the water has reached supersaturation levels but the air has not. As the saturated water comes in contact with the unsaturated air, the CO2 moves into the air which will more readily absorb the CO2. The only problem with this is the fact that water will hold 5 times more CO2 than air before it reaches its saturation point. From this, we can conclude that when we aerate, we will need to expose 1 unit of water to 5 units of air for proper degassing. In actuality, since no system is 100% efficient and since the contact time at the air/water interface is limited, it is often practical to increase this to as much as 10 times the volume of air to water. In this way, the air is not close to its CO2 saturation point and therefore will more readily absorb CO2. All this means is that if you use less air, it will start absorbing CO2 at a rapid rate but will slow down quickly as it becomes saturated.

Using an air blower is often another practical method of aeration. Blowers operate under low pressure ( around 3-4 psi ) so they can be placed underwater and the air allowed to bubble up through the water. If you do this, remember that the smaller the bubble, the more efficient your system will be. Often, allowing the air to exit through an airstone (not an oxygen diffuser!) then using a porous media such as Bio-balls or Koch Rings above the stones will add a lot of contact time to the system.

When you design your system, if you plan on using pure oxygen and will be raising fish at high densities you should keep in mind that you are trying to remove carbon dioxide and not add oxygen through aeration. With salmon or most other cold water fish, your discharge water should have oxygen levels nearing 100% saturation and after you reach 70 or 75% saturation levels, aeration is not an economical way to oxygenate your water. What I mean by this is that water going into your degassing system will often be as high as you can get it by aeration even before it enters the system.

Obviously Oxygen diffused open systems where the water is replaced all the time don't suffer from build up of CO2, however high livewell densitys of big bream can add a lot of CO2 quite quickly so aeration (via a 12 v aquaruium pump and stone and / or a venturi and/or surface jets) remains a requirement most especially in hot weather & warm water situations..

What we need of course is the super baitwell manufacturing co - to build these things for us at a decent (read cheap) price where they have "the lot!"...venturi, heat exchanger, aeration, water jets, pumps, drains in all the right places, oxygen infuser, filtered outlets, water level gauge - regulators for water inflow and outflow - as well as temp gauge etc - all "built in" standard!!!

Surely we have someone with a design bent here - any budding inventors among us?

Something that the breammaster shop can sell?

What If I make and supply em?...;) Better let me make a prototype first!

Cheers! :D

[fatman]

I use a home made recirculating system with a spray bar, and some added holes under the water as well to add some water circulation. I have kept fish alive in it for over 14 hours and travel 200 kms in the boat towing home. I know all this fancy stuff is good but is it really needed????? I know it's bloody expensive

here's mine, and only costs about $40

FATMAN

[fatman]

opps, here's a pic

Yeah Trouty thanks mate, I can see where your coming from.
I reccomend you pick up some of the mroe respected Aquarium books around. The bubbles and airstones are actually made to create surface tubulence. The bubbles dont really have an effect. I can see where your coming from in terms of the bubbles/spheres in large numbers, but tests performed by some of the most renowned Aquarists have shown that they really dont work. I dont know where the guys are putting the water input holes in the livewell. if it is in the bottom, then i strongly reccomend you do the bubble vaccum thing, as the bubles will create large amounts of turbulence on the surface, but if the input is at the top (above water level) then dont bother. it is just another thing to worry bout.

Dave

that a lot of the current livewells (recirculating and ater exchange types) will rpbably work really well for 995 of the breaming you do...lets face it we live in a temperate zone as these are temperate fish..and most of the time the water should be cool.

The biggest threat when that changes to a heatwave (which Perth has a few of) is O2 depletion and co2 buildup, as well as nitrates accumulation and the fact that aquaculturists keep fish alive in closed systems at quite high stocking densitys is proof these can be overcome too.

As for expensive - I know my diagram ain't that hot...and some of the components might initiially LOOK expensive (like the ~US$595 Oxygen infuser, and peltier device refigerator/heat exchanger) unit but like most of us - I ain't made a money so am looking ot tget the technology - without the price tag that goes with it.

So far I reckon I can likely make the refrigerator for the boat with heat exchanger etc so you cool your livewell water and also your days drinks (who doesn't wan't a fridge in the boat?, ever added up the cost of all the ice you buy?) for under 50 bucks!!!

I'll take a look at this oxygen diffuser next - I'f I can get to the bottom of this "swing technology" for removing pure oxygen from air - and find the right parts - I reckon we can make one a them for next to squat as well..

My aim is to try and design / build the "ultimate refrigerated/venturi aerated / oxygen infused livewell system" for any boat (remembering this will have application for tropics type baitfish etc as well - not just bream and bream boats), for under 200 bucks....

I was thinking to "unitise it...i.e make it like a large box that'll go in any boat (or car for aquaculturists/ aquariums types/tropical fish collectors etc), so anyone can just buy one complete...stick it in and plug it in and away they gooo..

Likely have to get em made in numbers in China to keep the end cost down, the parts for the fridge/heat exchanger are cheaper than 40 bucks.....from Dick Smith...brockoli boxes for the livewell and fridge (replaceable cheap when they are buggered) etc

Let me work on this Oxygen diffuser swing technology and see what I can find out.

Cheers!

[Fishaholic]

Originally posted by fatman
opps, here's a pic

I reckon your setup must work fine because the fish in the diagram is smiling and obviously happy with the oxygen and co2 levels :D ;)

Cheers,
Gab.

Trouty we got our wirs crossed mate.
I was referring to the Vaccum tube only. I didnt' read you refrigeration post, as it was too long and i couldn't be bothered!:D
I suppose it aint really expensive to put the tube in , but it is a hassle which aint really worth it!
Mate, I'm not gonna go back and read you fridge idea, as its not only long, But i cant see pic on this site from my home computer:mad: I'll take your word for it, it sounds like a good idea.

[jimi]

Yeah trouty, some of us are genXer's or even younger which means we are both cynical and have short attention spans:D. We were brought up on a steady diet of tv and playstation (ok SNES in my day). If you can't sum up your posts in a catchy phrase we probably won't get it anyway. ;);) Any chance you could summarise :p

Kingpin, why can't you see pictures? Do you have images turned off in your profile? Are you viewing this over a 14.4k connection or web enabled phone?

James

I'm actually running a dial up connection to my dads work!
All pics used to come up, bu then all of a sudden they stopped.
I thinks its the settings at the servers end, but i'm not sure.
Oh well... we get ADSL next month anyway!
Oh yeah, i have a good atention span, just that while on holidays from uni, the last thing i want to do is read long posts. However, i actually find trouty's posts very interesting.

Dave

[jimi]

Yes I agree with you that troutys posts are full of good info, but delivering info in smaller chunks would make it easier to get the point across.

ADSL is awesome. You can nearly view posts before they are written :)

Sheesh - just read s l o w e r - it works for me! ;)

You guys musta logged into the wrong breammasters - the one you want is at:-

http://www.readersdigest.breammaster.com :D :rolleyes: :p

Sorry - just funnin with ya... :)

OK - we're getting somewhere now, Kingpin you want me to email you that drawing - it ain't no leonardo davinci, but it's got lottsa pretty colours n stuff.....

Heres how any of you can make your own boat fridge/livewell water cooller with a few parts from down at Dicky Smiths..

this is long - so get clever - and like my "other long posts" copy n save em to a word document in your "my documents folder" as a file named "livewells" and when the time comes to make your own livewell - you'll have all the info you need nicely stored away for a rainy day!!!

Thats the beauty a 'puters you guys - you can save stuff and use it later when you need it.

It's not like you have to study and memorise every word I write - just skip / speed read, get the gist of it - save it for when you need it..

I dunno - next you'll only wana catch the little/easy bream! hehehe...

I've got a lead into this portable 12 V electric oxygen producing machine - just gotta get my grey matter around this new vacuum pressure swing adsorption (VPSA) system with their zeolyte O2 absorbtion beds, and we are home and hosed on the downhill run.

Now I just gotta figure out where I can get a few a these "zeolites' without breakin into a medical radiological research facility to steal em! :rolleyes: hehe - just kidding...

Wish me luck - this could be the start of something beautiful..

Cheers!

Maybe save this one!

Convert your esky to a fridge

To some people a boat fridge is a luxury item that they can afford to do without, more and more people are finding that there is a distinct advantage in having some type of cooler for those times when they are fishing and need to keep drinks fresh.
Commercial car fridges differ in their performance and design but they almost all have one thing in common: they cost a lot of money to buy new. The exceptions to this rule are the small imported fridges from Taiwan and China which can retail for as little as $100 in places like K-mart.
This project will show you how to make a fridge similar to those imported units, but at less cost, by converting a existing cooler or brockoli box into a boat fridge. Before we go any further, I should point out that if you are thinking of buying all of the parts brand new, don't bother, as it would cost more to do this than to buy a car fridge from K-mart. On the other hand, if you have most of the bits already, or can get them for low cost, then it is worth the time and effort and you will end up with a fridge of higher quality than the cheap imports.
How it works
The type of fridge we are about to build here is basically the same as the imported models and consists of an insulated container that has inside it an aluminium liner instead of the plastic found in a cooler. A special semi-conductor device known as a Peltier effect device is connected to this liner.
Peltier effect devices are as brilliant as they are simple to use. They consist of many small semi-conductor blocks all linked together and sandwiched between two pieces of high heat conductivity ceramic material. They have two wires coming out from between this sandwich, and nothing else.
So how do they work? Without going into a great amount of theory, you simply connect a 12 volt supply (the common ones available are 12 volt) across the input leads, and one side of the device will get hot while the other side gets cold. Simple, but they work.
I should mention here that these devices are in no way as efficient as a conventional compressor type heat pump, but considering that most boat fridges are used in the boat while it is running, the current they draw is provided `free' from the outboards alternator (while the alternator will draw more power from the engine to provide the power for the fridge, it is undetectable in all but the tiniest of engines).

Materials
So what do you need? Well first you will need a brockoli box.

The key to the success or failure of your fridge depends almost entirely on the insulating ability of the cooler.

Now you must get the Peltier effect device.

There are a couple of possible sources for these things, some cheap, and some definitely not so. If you have an old `el-cheapo' car fridge that has given up the ghost, you can bet it will have a good Peltier effect device in it, as these things - being solid-state -virtually never wear out. You may have one with a damaged case, and this is a good opportunity to recycle a few bits from it.
Some of the electronics components suppliers also have Peltier effect devices but at ridiculous prices (more than the cost of a cheap car fridge itself). I bought my device from Oatley Electronics in NSW, who sell a 40mm square Peltier device for $25. Now that's more like it!
You will also need a heatsink for the Peltier device on the outside of the fridge. This can either be salvaged from old electronic equipment, made up if you have the skill and the spare aluminium sheet, or bought at almost any electronics hobby store such as Jaycar or Dick Smiths. If you really wanna chill down quick - use more than one peltier device and heat sink & fans..anyting up to 3 or 4 if you like - 1 on each side of the box!!!

To make your fridge as efficient as possible, the heatsink should be as large as is practical for your fridge. As a minimum size, look for something about 120mm x 120mm x 35mm with around ten fins. The larger the heatsink, the lower the temperature difference from one side of the Peltier device to the other, so the more efficient your fridge will be at getting rid of heat. The inside of the fridge will need a heatsink also, to transfer the heat inside the fridge to the Peltier device. This will need a large surface area, and is best made by using a good size piece of 1mm thick or more aluminium sheet. The only other things needed are a fan to cool the outer heatsink, a heat triggered switch, rated about 100°C, as a safety in case the fan should fail (you will get both of these if you buy the parts from Oatley), and a small block of aluminium, about 50 x 50mm and a bit thicker than the cooler wall (including any insulation that you add). You can get this from your local aluminium stockist, or from a piece of scrap.
Converting the unit

Cut a hole in the side of the cooler, right through the wall, just large enough for the block of aluminium. Next you will either need to drill two 1/8" holes right through the aluminium block to take the bolts, if you are using a block thicker than about 25mm, holes from each end to take small, self-tapping screws. Now drill two holes in the outer heatsink, and remove any burrs from both the heatsink and the block.
Now you must make the inner heatsink. I used a piece of aluminium sheet about 200 x 600mm that was folded to fit neatly inside the cooler, in a `U' shape. You must now drill two holes in this sheet, at the base of the U, to match the block of aluminium. Also drill four more holes out further, and de-burr all of them.
Insert the aluminium block into the hole in the cooler, position the inner heatsink and screw them together. Now screw the heatsink into place with four short self-tapping screws or similar. Remove the screws holding the block, remove the block, and smear a coating of silicone heatsink compound (electronics shops) on the face that contacts the heatsink.
Replace the block into the hole in the cooler, and screw it back onto the inner heatsink. Put heatsink compound on one side of the Peltier device, position this onto the aluminium block, with the leads pointing down, the red lead to the left, and press firmly so that the excess compound oozes out. Without moving the device, wipe away the excess compound and then smear some onto the other side of the device.
Now you must position the outer heatsink and, using spring or tooth washers to stop it coming loose at a later date, pull the whole assembly tight. When doing this make sure that you tighten the bolts evenly, as tightening one first and then the other may cause uneven and excessive pressure on the Peltier device and may even cause it to fracture. The whole assembly procedure can be seen in the diagram.
To reduce the load placed on the Peltier device by the heatsink, you may want to do as I did, and screw the heatsink to the outside of the cooler for support. So that moisture does not accumulate between the inside of the cooler and the inner heatsink, you will need to run a bead of neutral cure silicone sealant completely around the inner heatsink.

Putting it all together
Now that you have done this, you almost have a working fridge. The only thing left to do is to wire up the device to the heat switch and attach the fan and cover. The wiring is so simple that a wiring diagram is not necessary.
You must first attach the heat switch to the outer heatsink. I did this with a screw and small metal clip made from a piece of springy steel. Remember to use heatsink compound on the switch as well. Now connect the red wire from the Peltier device to one side of the heat switch and then run a wire from the other side of the switch to a two-way terminal block mounted just under the heatsink. Now run the black wire to the spare part of the terminal block. Cut the fan leads to the correct length, strip the ends, and insert them into the corresponding positions in the terminal block with the wires from the Peltier device, and tighten the connections.
Now all you need is a lead and lighter plug so that you can plug the unit into the boats water proof marine ciggy lighter socket. I used two 1 metre lengths of 10A cable, twisted together, with a cheap lighter plug. The electronics stores sell these things for about $1.20.
To make the fridge safe, and because I was testing the unit straight from a battery, I included a fuse in the positive line at the fridge end of the lead. You may like to use one as I did or you may want to rely on the boats ciggy lighter socket fuse.
I personally recommend including a fuse in the lead somewhere, possibly in the lighter plug.
The final step is to attach the fan to its cover, and then to attach the cover to the fridge, over the heatsink, with four self-tapping screws. The fan cover can be made from any flanged box that will do the job, from a homemade aluminium or sheet steel job, through to a plastic lunchbox or similar container. The cover should fit as close to the heatsink as possible, so that the fan draws the air through the heatsink, rather than from around it.
A hole must be cut in the box for the air to flow through, and the fan is attached on the outside of this hole with four 3mm bolts and nuts. Once the fan cover is attached, your homemade car fridge is finished and ready for testing.
Testing your fridge
To test the unit, connect it to a large 12 volt battery and check to make sure that both the fan is running and blowing air in the right direction, and that the inner heatsink is getting cold while the outer one is getting warm. If all is well, you can put a couple of containers filled with water in the fridge, close the lid and let the beast run overnight. In the morning you should have some very cold water, and a working boat fridge to utilise as a livewell heat exchanger and drinks cooler that you built (and can fix) yourself.

Cheers