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Oceanic seafood production drifting fish cages

Home Forums Research Business Oceanic seafood production drifting fish cages

This topic contains 39 replies, has 6 voices, and was last updated by Profile photo of spark spark 1 year, 9 months ago.

Viewing 10 posts - 31 through 40 (of 40 total)
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    Profile photo of OCEANOPOLIS

    Hmmm, the link works OK by me and it’s safe…Here is another link about ferrocement, the plaster to use, etc, that you might find of interest. http://www.ferrocement.com/casa-ca1/ch1.en-ferroHouse-web.html

    Anyway, this is how the process works for building a rectangular float. You build the frame, using 2x4s or whatever size you need, spacing the frame’s “ribs” 1′- 2′ apart or according to the strength desired (the closer, the stronger). Turn the frame up side down and screw in plywood sheets in (use treated against rot plywood that you can buy at Home Depot). On top of the plywood skin lay your mesh (chicken wire) and staple it down. You can apply a stronger steel armature first and then the chicken wire if you want heavier duty ferrocement. Mix your plaster (portland cement+fine sand+water) or just use quikcrete+water and apply to uniformly cover the mesh. Let it dry and your’re done.

    For my application, 3/4″ thick plywood and 1″ ferrocement skin on top will be more than enough, in fact overbuilt. Keep in mind that the thickness of a fiberglass hull (let’s say on a 45′ sailboat) it’s about 3/4″.

    What I really like about this method is that you have an extremely strong hull (1 3/4″ thick) which is two layers, giving you a 2nd “back up” inner plywood hull in case the ferro skins cracks or gets damaged. If that happens, the plywood will hold. If damage to the ferro skin is above waterline you can fix in the water by filling with plaster and if bellow the WL, just pay the piper, haul out and fix just the same. The hull I described will be safe for coastal and some offshore cruising capabilities on a really low budget. (of course, up to certain sea state conditions,…maybe up to 30′ waves, if I’ll have to guess)

    In your case, for that cylinder (what kind of material is it, anyway?) use thinner mesh. (Home Depot). 1″ ferro skin will be more that plenty to cover. Just try to “attach” (staple, if you can) the mesh to the cylinder and make sure that your poor is uniform and you won’t have any problems.

    I sheathed a 5′ long scale model of a kite shape float like that, (about 1/8″- 1/4″ thick ferro skin over thick cardboard) so I can test it in the water and it came up nice and very strong. In fact, I dropped it about 4-5 feet on the kitchen tile floor, it hit with the bow and crack a tile, but with no major damage or cracks to the hull, just a little chip, that was all.

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    I plan on making steel reuseable forms, i have a 4×8 sheet of 14 awg plate outside now. I am sorta waiting on feedback about this cell idea before i do the inner form, because if i need to mold in reinforcing cross pieces it will get tricky to make the interior mold pieces removeable. I would rather not add interior bracing, as it will add to cost and weight and subtract from floatation. I am also debating with myself about making the top of the cylinder part of the casting or not, it really depends on how the cell is held in place, as to how thick it is, what sort of attachment points are set onto the cement, etc. It seems silly to make a cement float cell and then add steel attachment points, but the stainless steel attachments i set into the house wall when i cast them seem to be doing fine 14 years later. With the winter weather we are having now, i may not get to work on it for another two months anyhow, but if i can plan the design correctly then i need build it only once.


    I am not using “ferrocement” as building method. Concrete is a composite material consisting in cement, aggregates, and fiber (rebar). You can combine those three elements in many different and (hopefully) intelligent ways to have all kind of materials with all kind of properties you wish. What you describe as “ferrocement” is a method that sets up several elements in a way i am not happy with. Among these: Buy a boat to use it as form – can’t you think in cheaper more reusable ways to hold concrete in place for a while until it cures than “buying a wooden boat” or build one out of plywood? – i can. Use steelmeshwire as fiber component – very messy process, very hard to hold in the middle of the wall (where you want it) very nasty when it rusts (tears build apart due to volume increase) very little concrete matrix cover to be on the safe side. Can’t you think in ways to introduce “fiber component” more intelligent less messy, less rusting – i can. Plastering is a method to get cement material on your build – very prone to voids, seeping due to lack of compacting, especially if you plaster on mesh wire layers it is very hard to compact the mix properly. Can’t you think in methods that form a better more dense concrete matrix, that enclose the fiber in the concrete matrix more suitable – i can. Having this said i know that there are ferrocement shells out there that are well built and last for decades. There is also a lot of ferrocement building that lasts nothing and brittles away, because one ore more of the tipical ferrocement issues are not properly taken care of. All depends on the skill set and care of the builder – i also put to your consideration that none of the builds that are mentioned here – and that are 30-70 years at sea (deterioration free) as we speak use “ferrocement”. http://concretesubmarine.activeboard.com/f541915/outstanding-floating-concrete-structures-news/
    I would also suggest to just forget the “attachment idea” completly and replace it with “continous building of cells”
    As suggested in the ramform island, http://concretesubmarine.activeboard.com/t51926036/establishing-a-ramform-floating-base-in-the-high-seas-concre/
    But we are off topic – this is the “Oceanic seafood production drifting fish cages” – thread. So to discuss ferrocement please open a ferrocement thread.

    Profile photo of OCEANOPOLIS

    True, ellmer. But I think for small application (up to 80′ LOA) ferrocement is an excellent material. But you’re right, we drifted,…

    Back to the topic at hand, I am not a big fan of fish farming in the middle of the ocean, lol…, one would be better off just fishing straight up (much cheaper and profitable), BUT in the case of seasteading fish farming would make a certain dollar and sense because your are at sea all the time, so might as well fish farm,…

    In this case than, why use drifting fish cages which are more or less hard to handle and operate in the open seas? Just build the seastead “around” the cage, as shown in this design.


    If so, it will simplify the whole fish farming operation tremendously. From feeding (that can be done from the deck around the cage) to collecting the finished “product” (just hoist the cage up and move product to a processing area, refrigeration hold, or pack on ice for immediate export).

    Would it make more business sense, on a seastead?

    Profile photo of OCEANOPOLIS

    Plus, if you are running some sort of accommodations business on the same seastead (and of course you will), you can run daily activities like “swim with tuna, or yellowtail snapper”, or whatever you’re farming. (just don’t farm sharks :) Or, “swim with your meal”, or “catch your own meal” (you let them catch a fish out of the cage and charge them to cook it, lol :). Priceless for the landlubber!


    drifting fish farm

    A Drifting Fish Farm

    Kampachi Farms, a mariculture company in Hawaii, is devising a way to meet our insatiable desire for sushi with a farming method that has near zero environmental impact. By filling 100-ft. (30 m) copper-alloy mesh cages with fingerlings and letting them drift, tracked by GPS, in deepwater ocean, the company hopes to harvest thousands of tons of sustainable sashimi-grade kampachi. In 2011 it tested 20-ft. (6 m) pens 3 to 75 miles (5 to 120 km) off Hawaii. After six months, they yielded 10,000 lb. (4,500 kg) of kampachi, which grew twice as fast as expected.


    The fish farming business is up and running – what is difficult to perform is the “living quaters for the farm workers” – Neil Sims is proposing to “run it like a space station” – no works on the surface at all, no heaving of cages, no platform to stand on… avoid the surface as the unpleaseant part of the operation. See Neil Sims in video..

    Profile photo of i_is_j_smith

    how do i attach them to a structure in a way they don’t shatter?

    You don’t attach the mooring system at all. If you’re talking about using a sphere like ellmer then I would use some kind of netting, like this:

    Sphere netting

    Then you simply attach the looped part to a mooring line (or lines, preferably) and you’re set. There is no single attachment point to act as the single point of failure, or that takes all the stress.

    You could use this method even if the submerged habitat wasn’t a sphere. It would work fine for fish cages as well…

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    I have macreme’d those and made a few bucks doing it. For a cement floatation cell supporting 1000 pounds each, i was thinking more of chain than rope. There’s still a chaffing problem against the cement unless i add steel bumpers. And the ocean can wear a chain thru in a year, with the floats swaying back and forth under load every minute of every day. Plus if you have floats swaying around, you must allow space for them to not impact each other. There’s definately plusses to hanging the structure by floats like that, but i haven’t solved those problems yet either.

    I was hoping to do it on the cheap, clustering as many as required right on the legs, as low as possible, nearest the load. If i need to allow space for the swaying of the cement cells, they must be spaced from each other and the very leg they will be supporting, which is going to add to the materials list and make for offset stresses. I believe the cells i am thinking of can survive being restricted from moving with swells if installed 30ft or deeper, but i also believe some motion, flexing, mobility, is needed in whatever is capturing them around the legs, no matter what the leg is made of, even if it is a huge cast concrete heave plate. I figure than partly because underwater tends to move in circles, so one end of the cell may not be trying to move in the same direction as the other end, but anywhere it’s attached is probably not going to be a perfect mate-up surface. I was going to capture the top and the bottom.

    Profile photo of OCEANOPOLIS

    The blue sphere is just nautical art guys…There are a bunch of fenders out there, from used tires to Taylor Made (http://www.boatcovers.cc/cgi-bin/catalog.pl?item_id=6) to really heavy duty ones (http://www.blueoceantackle.com/pneumatic_marine_fenders.htm), etc.

    Profile photo of spark

    Hydroponics Gardening Information Blog
    Friday, January 13, 2006
    Hydroponic Rice Crop
    The Times on Thursday, 12th January (2006)
    The article can be found on page 4 under section 44 world news.
    An interesting article appeared in The Times on Thursday 12th january. It appears that the Japanese have perfected the art of growing rice without paddy fields. An experimental lab, set up in an old security vault, has finally produced the goods after many years of trials and mainly errors.

    The breakthrough came when an old rice farmer, with 40 years experience, was asked to look at the crops which kept failing. His immediate reaction was that there was “no wind and no rain”.
    On installing fans and raising the Oxygen Levels in the nutrient to simulate rain the plants thrived.

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