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JamesMusslewhite

Building a Floating Net Platform for Lobster 'grow-out' Aquaculture

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JamesMusslewhite
Posted (edited)

  

   This is a spin-off thread from the 'Building a Small Lobster Hatchery here in the Philippines' https://www.livingincebuforums.com/topic/95658-building-a-small-lobster-hatchery-here-in-the-philippines/ which will be discussing several types of floating nets and floating cages which I will eventually be constructing to use for the lobster hatchery facility. I will be not only raising lobsters from eggs but will also be raising various saltwater species of fish, crabs, shrimp and assorted shells to be used to feed the lobsters being produced in the hatchery. This need will require several different styles of floating nets and cages. This is why I felt that by grouping these into a separate thread it would help the readers to more easily follow the information while allowing the hatchery thread to remain less cluttered.

   My first net system is a large multi-purposed floating platform which will be used for lobster 'grow-out' aquaculture. We will be purchasing Pueruli and Algal-juvenile size seedstock and will be raising them to 500gram size buyer's market weight. This is what is called lobster 'grow-out' aquaculture. This first floating net platform system though built for open-water lobster 'grow-out' aquaculture, is a design which is adaptable for both freshwater and saltwater 'grow-out' aquaculture.

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   When I first sat down to design this platform I knew what I wanted to use it for, and I understood that it would have to meet certain criteria. First I knew that I wanted a (6 meter x 6 meter) floating net-platform. The platform needed to have a large net enclosure capable of performing several different functions at the same time. The platform must be capable of handling the stresses of moderate to heavy wave action (Cat-2 to Cat-3 tropical storm), and capable of being quickly relocate to a more sheltered location in case of typhoons. The frame needed to be constructed out of a durable lightweight medium which is affordable, yet both extremely strong and flexible as to not easily buckle by heavy wave action; which of course made (single-length bamboo construction the best option). And the the platform needed to be constructed with a sufficient height above the waterline to protect the walkways from heavy wave action, and handle the wear from boats which will be lashed to the frame during normal day-to-day usage. Well that certainly seemed easy enough at the time, but it quickly turned into quite a task which took some time to take it from concept to reality. 

.   When I first started sketching out the platform I decided I would look at some examples on the internet to use as an example. Well I quickly discovered that there was actually very little on the internet and what was available offered little in the way of useful information. In fact it became clear that what sketches were on the internet were not actually sketched by someone who had actually built one before, as there lots of artistic license being employed in their sketches. This is the closest drawing off the internet which I could find to the design I was working with in my head.

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So I decided to stop looking for assistance on the internet and just start sketching a long series of rough drafts and drawing until something that appeared to be a feasible working design stated to evolve into something that seemed practical. I then sat down and made a working model using plastic straws, bamboo toothpicks and sewing thread and built a prototype.

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   I knew that plastic straws reacted similar to lengths of bamboo when stressed, and that the plastic straws displayed a similar flexibility to that of bamboo lengths. This allowed be to build a platform in miniature, which I could easily hold in my hand and twist and flex.

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This would allow me to simulate the stresses the platform would most likely encounter during heavy wave action. I would test, discover the flaws in the design and build another straw model and test that one, and so on and so on.

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I was able to strengthen those areas in the design which had weaknesses, and trim-down all unnecessary weight while maintaining the integrity of the frame. Eventually I had a simplistic design which was extremely strong but required a minimum of building materials which would help keep the material cost low for the project.          

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   I now knew that I had the design just as I wanted. The model also allowed me to already assemble the platform; so I was confident that all the needed bamboo lengths, bracings and sections connecting the 55gal plastic drums to the frame were correct. All the materials had already been collected and the bamboo had been properly dried, so now it was time to assemble this project so we can get it in the water for real. 

Edited by JamesMusslewhite
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Alfred E. Neuman

How much will this cost you?

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JamesMusslewhite
Posted (edited)
2 hours ago, Alfred E. Neuman said:

How much will this cost you?

   At this point I really can not tell you for several reasons. This being a prototype I have nothing yet on which I can accurately measure or gauge even an educated guess. My brother-in-law is helping me to build the platform as I trust his skill with both working with bamboo and the lashing of the bamboo using #150 nylon line. He is the man I used when building my 'Arthur 1' pumpboat in the total pumpboat rebuilt thread I posted a few years ago on the forum. The bamboo being used in the construction of the bamboo platform is coming from a property which has 8 hectors of bamboo owned by my business partner. He is also handling the labor costs, equipment and fuel costs of transporting the bamboo to this island. Once the project is completed and I can get his costs, then I can calculate the total material used as well as an intelligent estimation of the overall costs if one had to purchase the bamboo from a dealer.

  I also still have to calculate the exact number of meters for each of the nets which will be used in and around the platform as well as the shade cloth covering that will be over the larger main net. So I will have to collect accurate numbers on the remaining material and labor cost, as well as a reasonable estimate as to the length of time required to properly build a platform this size. Once I have collected all these figures I will be including a complete itemized list to the thread.  

   This platform system will be using three various size nets inside the outer walkway, and at least eight different nets which will be under the bamboo walkways. Lobsters will be raised in the center three nets. One will be the large net which will house the late-juveniles and Sub-adults. Then there are two smaller nets which will act as a nursery. The first nursery area will be used to house Pueruli which are both fragile and in a non-feeding phase of development. Once the pueruli Instar (moult) to Algal-juveniles they are quickly separated and place in another nursery net enclosure. Algal-juvenile are voracious and highly prone to acts of aggression and cannibalism. They therefore need to be isolated and placed in an enclosure which can provide sufficient shelters and can be placed on a tightly controlled feeding regiment. Due to their much smaller size than the Late-juveniles and Sub-adults, these young Algal-juveniles still need to be kept separated until such time they have developed to the size that they can be added to the main body. 

   This net system I have designed is unique as it can house three different sizes of lobsters in one enclosure, yet will still allow Late-juveniles and Sub-adults total access to the inner floor space of the large net enclosure. This is because the two nursery nets are shallower in depth allowing the Late-juveniles and Sub-adults access to dwell under the nursery nets. Also when not needed these two nursery nets can be easily removed and stored until such time they are needed to be used again, and they can be quickly setup at a moments notice allow flexibility while not causing any disruption to the main grow-out stock. This platform will have another unique was the lobster being housed in the main net will be completely surrounded on all sides by individual nets located under the bamboo walkways. These nets serve two functions. 1.) it provides protection by greatly reducing the possible of theft to the valued housed in the center nets. 2.) it provides net spaces where species of feed fish, shrimp, crabs, shells and other assorted species can be raised.   

   I have much of the platform completed and will hopefully get it uploaded to the thread later today or this evening.

I am presently experiencing issues with uploading photos onto the thread. Every attempt at trying to upload photos today (and there has been many) has been unsuccessful as I quickly receive a '200 timeout notice' I have repeatedly exited and restarted the thread and both dragged and dropped photos and used the 'choose files' feature but nothing seems to work. And as It seems to be no issue opening threads and navigating through the forum, than perhaps it is a forum gremlin, over-tweaking of the forum software settings or the monkey simply threw the wrong switch. :any-help:

Edited by JamesMusslewhite
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BryanWill123

Thank you James, very informative. You refer, I think to the placement of the netting as providing security. How in general would you protect such a valuable crop from being just towed away in the middle of the night?

thanks

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JamesMusslewhite
Posted (edited)
3 hours ago, BryanWill123 said:

Thank you James, very informative. You refer, I think to the placement of the netting as providing security. How in general would you protect such a valuable crop from being just towed away in the middle of the night?

thanks

 

   Excellent question and is one which I have given serious thought to as I designed the floating platform and contemplated the exact placement where I want it located. There are three different security features which will be incorporated in this floating platform. First are two heavy cables each attached to a screw-anchor mounted directly into the seabed (similar to the screw-anchors used on mobile homes in the US), with the other ends wrapped around the framework of the platform and padlocked. These two cables meant as a fail-safe to insure that if the anchor ropes and mooring lines fail that the platform will not do into an uncontrolled drift. these are to protect the platform during excessive high tides and heavy wave action which would be experienced from a direct assault by a Cat-1 or Cat-2 tropical storm. i believe this platform could endure a Cat-3 on the inlet side of the island where it will be positioned.

   The second is two security cables which will run from the platform frame to an ironwood support pole of the lobster hut which will be sitting directly behind the floating platform. And the third security measure will be a series of security poles that will be mounted on the nearby power pole and on the Lobster hut. These will have motion detectors and will illuminate the floating platform. The platform will only be perhaps 30-40 feet offshore almost directly in front of our front gate. There is also our neighbors who fish around this island to catch food for their families and their own lobster huts. This is a very tight-net community who depend on each other to keep a close eye on strangers. They simply can not tolerate lobster thieves in their mist so these lobster farmers are well networked and they watch out and cover each other's backs.    

   Now if someone does try to be so stupid as to try to steal the platform, then they will have to sneak up in a boat without being observed by the late-night fishermen, cut away all underwater cables and anchors all the while avoiding the motion detectors and security lights. Without making a sound as to avoid alarming the dogs on the island and all those on the neighbor's huts. I am usually up every night until well after the roosters crow. And If i hear an odd noise or the local dogs start barking, then odds are I will quickly be somewhere lurking in the shadows with night-vision capability and 180 live rounds.  I would not want to shoot locals over a batch of seabugs but thieves better be excellent swimmers, because I will be quickly sending their plywood boats to the sea bottom.

Edited by JamesMusslewhite

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JamesMusslewhite

   First I had eight 55gal. plastic barrels delivered to the island. It is important that the plastic barrels are food grade and have only contained proteins because you do not want to use any barrel which has been used to contain chemicals. This is because it is not uncommon for plastic drums to leak around the threads of the two plastic bungs. This is because the barrels experience surface stresses caused by the weight of wood or bamboo laid across their surface and the up-welling forces of the water underneath them. There is a certain flexibility to the surfaces of 55gal plastic barrels especially when exposed to direct sunlight as the heat up both on the outer surfaces as well as in the inside. When used for floating platforms the wave movements and the movement of personnel on top of the platform can and often does seep both air and water into and out of the plastic bungs of a plastic barrel. A barrel which was used to contain a concentrated toxin risks leaking toxic contaminates into the environment of your net enclosure. Always ensure the barrels have only been used only to contain food grade proteins, and thoroughly clean inside the barrels. I also suggest that Teflon tape (plumber's tape) is used on the plastic threads of the bungs, and that the plastic bungs are thoroughly tighten to minimize seepage and maximize the buoyancy of the plastic barrels when they are deployed

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There has been two large bundles of fresh-cut bamboo delivered to the island. fresh-cut bamboo is moist which makes it more difficult to cut as the moist sawdust tends to bind the saw-blade. I sort through the bamboo lengths to separate and size them. Then I let the bamboo to dry for 2-3 weeks before I start to assemble the floating platform. The reason for letting the bamboo have time to dry is so the bamboo to shrink. If you start lashing together green bamboo it will shrink as it begins to dry. This will loosen the the lashings and weaken the frame. 

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   The bamboo was easier to tie in bundles with rope and then pull the tied bundles behind the boat to the island.  

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So after all the drawings and the building straw models, it finally reached the time when I could finely start building the beast. I always love starting a new project 

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First I start cutting the long lengths so I can build two sides of the platform. The frames which will be placed on top of the plastic barrels will be the first items built and six of these frames will need to be built.

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JamesMusslewhite

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JamesMusslewhite
Posted (edited)

   The bamboo lengths are cut to the desired lengths and lashed together using #150 nylon line. A paddle bit is used to drill a small hole in the bamboo and the #150 nylon line is threaded through the bamboo sections and then lashed together. This makes a strong union and is the same technique used to lash together the outriggers on boats.

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Edited by JamesMusslewhite
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JamesMusslewhite

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JamesMusslewhite
Posted (edited)

Well at the time of this photo we had two sides of the frame already prepared for the next phase of the construction, so it was time to carry them outside of the yard where we could begin assembling the main frame body. We had a nice location which was accessible to electric, had fair shade coverage and was close to the shoreline. I was excited after all the time designing, building and testing models and having to wait until it was time to finally build the prototype. This was actually the first time I could see true full-size dimensions of the platform. The inner net area will be slightly over 5.8 meter x 5.8 meter (19 feet x 19 feet).

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The concept is simple. Place one of the two sides which has already been assembled next to the shoreline and the other up on land. Then place 3 long lengths of bamboo at each corner. This was to make it easy to lineup the edges of the bamboo lengths, and use a square to insure we were working with 90 degree angles. Then we were able to lash the long lengths to the squared side at the edge of the shoreline. 024.thumb.jpg.0fc8380c8b1fc7c8bb8072d50cb31ae6.jpg

   Each side of the platform serves as a walkway, and each of the four walkway will be constructed using 13 long lengths of bamboo This will give the platform incredible strength, but will also be flexible and durable which in important during heavy wave action. Once the first corner is lashed then we move to the next corner and do the same.

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   All the lashings is done using a quality (heavy duty) #150 nylon monofilament line. It will hold up to the tropical heat and intense direct sunlight UV, and will surely outlast the bamboo which it is tasked with holding together. The life of the bamboo platform should be between 2 - 3 years.

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   once the 3 long lengths on one corner was thoroughly lashed together, we then moved to the other corner.

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   And we had moved on to the second corner. Now I bet that at this point some of the viewers have noticed those small trees, and are wondering what kind of a carpenter worth his weight would build a square shaped platform in the middle of trees? I am certain that those local folks watching us had that though, and figured we might have to be cutting some trees. But there was a method to our madness as you will see in the next photo .

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   The second side was merely a large worktable at this point. Once we had both corners of the shoreline properly squared and completely lashed together, we simply pushed the second side forward. Most of the construct will be pushed into the water to float as the construction continues. Then when needed the second side will simply be picked up and carried to the shoreline side of those small trees and lashed to the main frame. The whole frame then can be easily rotated as we work on all the braces. As my wife operates a small daytime resort on the island, doing the construction in this manner allowed us to stay out of the way of her customers, but also allowed us to continue working pretty much undisturbed. The humorous thing is when we take a brake either adults want climb on it to take selfies and glamor shots, or the small children want to climb out on on it to dive in the water. But when we are working on the platform they leave us alone.

 

 

 

Edited by JamesMusslewhite
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JamesMusslewhite
Posted (edited)

   This photo shows how the second side became a temporary second work top.

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then as we pulled the first side into the water, we carried the second side and placed it in the same location as the first side previously was. then the six long bamboo lengths were lifted up on top of the second. Meaning no trees died while making this forum thread.053.thumb.jpg.3ca54b64d10963072dd2a35e1064b700.jpg

   now we simply positioned, aligned and squared the long bamboo lengths as we lashed each of the remaining two corners. Bamboo can be a difficult building material as lengths are rarely straight, are thicker at one end than the other and are inconsistent as to size.   054.thumb.jpg.0305f88bacea67f7ebe2b48f7beed6c1.jpg

   You want to always want to cut bamboo close to the not as it strengthens lengths being lashed, if you cut the knot off then you have a narrow-walled tube section which ca easily crush, collapse, split or splinter.  Unlike lumber which can be cut at exact lengths and has a consistent thickness, each length of bamboo is unique as the length, thickness, size and circumference. The best you can do is get grenade-close. You can not make bamboo conform to you, rather your going to have to work with what bamboo gives you. But bamboo is inexpensive, light-weight, strong and the best material for this task.060.thumb.jpg.5eca6e5950d4ef7fb4dd483f87501515.jpg

   We still have a long way to go before this project is complete

073.thumb.jpg.492725236d712941b719a60f669f6a4a.jpg we still have plenty of bracing  which needs to be added, mounts for two more 55gal. plastic barrels, railings, two ladders,and other features before we even start dealing with making the nets. I058.jpg

   So I hope you have found the thread interesting so far, as we still have a lot more to cover.

Edited by JamesMusslewhite
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JamesMusslewhite

For three days I have been trying to add additional posts to this thread from my computer. It has actually taken less time to build the platform than it has taken to post a photo of that days work. Dozens and dozens of consecutive attempts using either the ''drop file'' option or the ''chose files'' only to quickly timeout and receive the following pop up message.   

                    There was a problem processing the uploaded file. -200

Perhaps there is an issue with your uploader or it's settings as a 3meg jpeg photo really should take 3 days to unsuccessfully upload. 

 

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BryanWill123

Yes, very interesting. Thank you for posting despite the difficulty.

Another question. Is it a concern that because of wave action, the bottom of the net cages may rise and fall violently ( in a storm,for example) injuring the lobsters?

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JamesMusslewhite
20 hours ago, BryanWill123 said:

Yes, very interesting. Thank you for posting despite the difficulty.

Another question. Is it a concern that because of wave action, the bottom of the net cages may rise and fall violently ( in a storm,for example) injuring the lobsters?

   Yes when either in open sea or locations facing open sea as large can easily develop. But if located on the back side of islands were they are far more sheltered, or pulled into a shallow cove or lagoon then this is really not a major problem. Lines with attached weights are tied to the underside of the platform frame, which are spaced at width wider than the netting. These weighs help keep the bottom and sides of the netting to be more taught, and helps prevent major sagging towards the middle and bottom of the net enclosure. This helps prevent the netting from collapsing in the corners, fluttering.; or being battered around by the currents, winds or swelling motions caused by the wave action. This helps to insure any injuries to the lobsters being caused my the movements of the netting can be minimized. A platform such as this one is designed primary for locations with light or moderate wave action such as a Cat-1 to Cat-2 tropical storm, but would need to be relocated to a more sheltered location if in the path of a typhoon.

   I also am a firm believer in the use of 'mesh bundle' shelters, which are small loosely bunched bundles of netting, which are tied directly to the interior bottom of the net enclosure. There are two primary reasons for the use of 'mesh bundles'. One is to help protect lobster during their Instars 'molts' by providing shelter while they are most vulnerable from acts of aggression and cannibalism. 'Mesh bundles' also reduce environmental stress within the enclosure, which helps maintain their natural immune system and aids to stimulate food intake and weight gain. During heavy wave events these 'mesh bundle' shelters allow serve as a soft environment, above the netting of the bottom surface. This soft mesh environment within the bundles themselves allows the lobster within the enclosure sufficient surfaces which to cling and safely shelter in place. 

   For raising lobster in the deep-water open-sea environment I would use a much heavier constructed floating cage system which is either round or hexagon shaped. This is because they are less effected by heavy action. But before expected heavy storms with the potential high winds it is always best to relocate the cages to more sheltered locations. Mooring can fail causing free-drift of the cage unit or heavier than expected tidal surging combined to excessive wave actions can seriously batter the frame. causing loss of buoyancy. I have even heard of cages flipping over onto themselves, sink to the ocean floor or major netting failures causing the total escape of housed stock. There are some cage systems designed to be sunk in place before a major storm hits, which can be easily reinflated back to the surface once the storm has passed. These systems simply ride out a storm at a depth well below the damage zone of the storms, without harm to the cage system or the housed stock. 

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