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Position Control

Home Forums Archive TSI Engineering Position Control

This topic contains 38 replies, has 17 voices, and was last updated by Avatar of ellmer - http://yook3.com ellmer – http://yook3.com 3 years, 9 months ago.

Viewing 15 posts - 16 through 30 (of 39 total)
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  • #5560
    Avatar of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    Just wanted to give you some feedback. Anchor rode is expensive because is (usually) 3 strand nylon. Its about $1-$2/ft (used) depending on the size. Even if u dont use chain and u might go only 5 to 1 scope ure still looking @ 65000 feet @ min $1/ft =$65,000.00. For that money , in this market , I can buy a 40′ sailboat ready to cruise, right now. It will be much, much, cheaper to just run the engine once in a while and drift,…as I was sugesting.

    #5563
    Avatar of wohl1917
    wohl1917
    Participant

    …I worked it out to 53.16 miles until I realised we were both doing the equation wrong! We forgot the last step: the answer is C-SQUARED which is 28.284 miles. Also, the lines could overlap by up to half that distance and not get fouled due to the vertical separation so we’re looking at just over 14 miles…

    Oceanopolis, no harm/no foul but the answer is yes: I have anchored before and do know SOMETHING about it! Yes, it would be expensive but no where near as expensive as dynamic positioning as has been proposed. What’s more I agree with you on drifting as a plan for small Seasteads but for a Seastead to become an economic center would require a fixed, more or less, position.

    #5565
    Avatar of Carl-Pålsson
    Carl-Pålsson
    Participant

    I think I took the square root of C… I still get the distance between vessels at anchor to around 10 times the depth, assuming a scope of 5, for instance.

    Intuitively, at a scope of 5, the lines will be reasonably close to horizontal, meaning the radius will be close to 5 at a depth of 1. That is a distance between units of almost 10. This makes sense for me at least. Am I missing something?

    I agree you probably could overlap the circles somewhat. It´s still a long way if you are trying to create a community.

    Using more ropes is an option of course. With three you could remain pretty much on a fixed spot. But it´s three times the money and labor. And with a number of units anchoring at the same place the ropes might start to tangle anyway, when dropping and pulling up the anchors.

    #5579
    Avatar of wohl1917
    wohl1917
    Participant

    My point is that Cousteau proved that it could be done and he did it in much deeper water than we would have to. Once you set your hook, your location would be fixed, more or less because currents in the open ocean are constant, flowing in the directions they flow so your location would actually be a 18 mile cone formed from a point up stream assuming a depth of 13,710ft…

    #5964
    Avatar of jcrawford
    jcrawford
    Participant

    wohl1917 wrote:

    What’s more I agree with you on drifting as a plan for small Seasteads but for a Seastead to become an economic center would require a fixed, more or less, position.

    I’m not completely certain about the necessity of a fixed position. It’s unlikely that platforms will get in to businesses that require a large amount of freight (desides fish-related activities, and deep-sea fish-farms are already in a pretty fixed position), reducing their freight needs to incoming supplies. It seems that as long as some kind of central registry of the current locations of platforms was kept, moving platforms wouldn’t be too much of a problem, as long as platform operators understood that the farther they went from other platforms and mainland ports the more impractical and expensive shipping in supplies would be.

    The situation where I see moving platforms being very annoying would be if regular delivery routes were developed. That would be the cheapest way to move things around, as dedicated trips for each platform delivery would be more expensive. Nonetheless, I think clever shipping models, like the use of UAVs as someone recommended, might minimize this issue.

    #5967
    Avatar of Hephaeston
    Hephaeston
    Participant

    Anchor chains are used so the rope doesn’t get cut on the bottom. Chains weigh a lot, so once you’re using them you might as well make the anchor weigh less. The real problem with anchoring in deep water is unless the line you’re using is neutrally buoyant or close to it, it has to hold up the whole weight of every piece between the vessel and the ocean floor, *in addition to!* the forces acting on the vessel. When they were doing the first relatively complete surveys of ocean depth (not anchoring) they had to use telescoping wire. The stuff at the bottom holding the weight, instrument, whatever, was like 12 gauge wire. The stuff at the top was inches in diameter. Granted they didn’t have nylon line at the time, and maybe you could make line that doesn’t have to hold itself up (maybe that’s why Cousteu could do it). That said … that is a whole lot of line. It’s not just the one time cost either, when you lose an anchorline (and you will, repeatedly) it’s not like you’ll be able to find the ends and patch it back together. Hopefully it breaks at the bottom so you can keep most of it, if it breaks at the top you’re out several tens of thousands of feet of line, and several tens of thousands of dollars … and if you have several of them? So then there’s storage space for spare line … I’m just saying you’d need an entire division of the seastead devoted to anchoring operations.

    The thermoclines aren’t that deep, makes a lot more sense to me to run a spar, kite, whatever down 200 or 600m to sail off the currents. We would need a major proof on concept on that, though.

    #5971
    Avatar of wohl1917
    wohl1917
    Participant

    ran into the problems you’ve mentioned and in the article, and the associated articles, explained how he solved them. He used a 200lb stock-less (navy) anchor, 100ft of chain, 300lb iron weight and an unspecified length of steel cable attached to a 3/8in nylon line. He anchored the Calypso weighing in at 360tons in 24600ft of water to a 3/8in nylon line… The thermocline sail idea is intriguing but would have to be proved. In any case as I see it the Seastead itself would not be anchored to the bottom it would be attached to a mooring the same way that ships and boats are.

    As to the necessity of a more or less fixed position, customers and visitors in general have to be able to find you! The ocean is a big, big place even with GPS, radio direction finders and radar people still get ‘lost’. In order to avoid interference from the macro nation/states your Seastead would have to be far out to sea but close enough to the established sea-lanes so that people can detour off their base course and come ‘a callin! Also, JC when you’re talking about ‘freight’ and ‘regularly scheduled deliveries’, you make it sound like a floating Wall-Mart (God forbid).loll;) The people living on Seasteads, like the Cruising community today, would necessarily be more or less self sufficient like the homesteaders of old, ‘sailing’ across the prairie in their Conestoga waggons.

    #5972
    Avatar of jcrawford
    jcrawford
    Participant

    wohl1917 wrote:

    As to the necessity of a more or less fixed position, customers and visitors in general have to be able to find you! The ocean is a big, big place even with GPS, radio direction finders and radar people still get ‘lost’. In order to avoid interference from the macro nation/states your Seastead would have to be far out to sea but close enough to the established sea-lanes so that people can detour off their base course and come ‘a callin!

    This would be the challenge of moving platforms. I think it’s simply a factor the platform’s residents must take in to consideration, though – the farther they go from ports and established sea routes, the more impractical (and thus more expensive) getting things to the platform would be. Hanging near established routes would definitely be a good idea, as it makes it much more practical for people to ‘hitch a ride’ on vessels already going somewhere, which would be much cheaper than a dedicated trip.

    wohl1917 wrote:

    Also, JC when you’re talking about ‘freight’ and ‘regularly scheduled deliveries’, you make it sound like a floating Wall-Mart (God forbid).loll;) The people living on Seasteads, like the Cruising community today, would necessarily be more or less self sufficient like the homesteaders of old, ‘sailing’ across the prairie in their Conestoga waggons.

    As I note, I’m thinking the volume of physical deliveries to a platform would be very low. There are still things that are not practical to create on a platform that platform residents may still desire, however. Think beef – ‘cattle platforms’ seem solidly impractical. These would need to be physically delivered. Platform residents would have to become used to less of this kind of thing, certainly, but I still expect that most platforms will receive regular shipments from the mainland (and certain types of businesses may be sending regular shipments to the mainland). The volume on these would probably be small, though, likely less than once a month.

    I knew someone that spent a year on a small island outpost as part of a biological research project. They received shipments (actually via helicopter, because they were close to shore) once a month, and lived pretty comfortably. This could easily be done on platforms, especially considering that platforms would be even more self-sufficient – the use of wave power and wind power, and the use of wind power for propulsion minimizes the need for diesel fuel to hopefully near zero, while the island outpost needed regular delivery of fuel to power generators. I believe they were also receiving drinking water via helicopter. So a platform shouldn’t have trouble getting by with physical contact less than once a month.

    #5973
    Avatar of Carl-Pålsson
    Carl-Pålsson
    Participant

    Self sufficiency is not an option. Very few people have ever been self sufficient, most of them only by accident, and all of them have been a lot poorer because of it. Trade is essential if you do not want poverty.

    Where will you get your computers? Refrigerators? Outboard engines? Tools? Clothes? Pencils? Will you make all these things? Of course not. You will trade for them, or you will not have them.

    #5974
    Avatar of wohl1917
    wohl1917
    Participant

    There are finished, manufactured goods that could not be produced on a seastead just as there things that the homesteaders didn’t have but, by and large, when they put out they carried out bound with them everything they would need to either get from point ‘A’ to point ‘B’ or to ‘get the farm up and running’… A Seastead with its floating seaweed/abalone racks, fish farms etc., are ‘The Farm’. More importantly, poverty is a state of mind! Most of the things we take for granted today didn’t exist 100 or even 50 years ago. Were the people who lived then ‘impoverished’? I think not. I agree that to obtain those finished, manufactured goods trade IS essential but what kind of trade? Some goods surely, but most likely Seasteads would provide services as well.

    #5975
    Avatar of jcrawford
    jcrawford
    Participant

    wohl1917 wrote:

    I agree that to obtain those finished, manufactured goods trade IS essential but what kind of trade? Some goods surely, but most likely Seasteads would provide services as well.

    I don’t see seasteads being competitive in the physical goods industries. The immediately available option for physical goods would be deep-sea farmed fish, but there’s only so much of a market for that. Deep-sea mining might become a possibility, but that’s certainly not practical right now. Seasteads simply do not have the natural resources to be competitve as goods producers. The seastead economy would be, as I see it, focused on nontangible products. With the modern information-economy and the powers of the internet, seasteads can make a profit providing information services, consulting, creativity, and other “information products.” Nontangible products require no natural resources per-unit, making it easily possible to create them out on the ocean, and they can be distributed via the internet, eiliminating the not insignificant cost of getting physical goods to and from seasteads.

    #5977
    Avatar of Thorizan
    Thorizan
    Participant

    It would be foolish to live on such a resource abundant seascape and not utilize its bounty. Slow moving objects at sea will attract thousands of fish. If you aren’t going to do anything about them… would you mind if I ranched them up and make a hefty profit?

    __________________________________________________
    There is no fate but what we make for ourselves. Each to his fate.

    #5978
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    How far away from the next anchoring seastead must you be in order not to cross your lines?

    If anchoring radius is an issue, why not focus on vertically moored structures like TLPs and ETLPs? There are several of these types of structures that are moored in depths greater than 1100m. While that might not work in the deepest areas there are still plenty of locations where this type of mooring system would be viable.

    Most of the things we take for granted today didn’t exist 100 or even 50 years ago. Were the people who lived then ‘impoverished’? I think not.

    I don’t like this logic. You know what else they didn’t have 100 years ago? Penicillin. Antivirals. Vaccines against polio and MMR. Air conditioning. Were they “impoverished”? By my standards, you bet they were. They wouldn’t have considered themselves “impoverished” because they didn’t know any better. I will bet you a shiny nickel that if you took Pasteur into our time period and showed him the medical products we have available he would look on his 19th century society as backwards and poverty-stricken.

    If you expect me to live on a seastead without acetaminophen, or vaccines, or a computer you are crazy.

    I expect fresh water to be a vital export, along with other aquaculture products. I doubt tourism will ever be a huge service, and I doubt information services will ever be big.

    #5979
    Avatar of wohl1917
    wohl1917
    Participant

    We’re going off topic here, so let’s bring it back in a bit… Vertically moored structures would be great if we had a deep sea mount that was not already claimed by some macro nation/state, but they are so we’d have to discover it ourselves! As posted earlier the deep ocean averages around 13,000ft deep and the Continental Shelves where vertically moored structures are used average around 1,300ft. International treaties in place now give those Continental Shelves to the countries they border, 3 mile Territorial Limits and 12 mile Economic Exclusion Zones not with standing.

    #5984
    Avatar of SailorTrash
    SailorTrash
    Participant

    …first, including the anchoring: http://encarta.msn.com/sidebar_761593515/cousteau_explores_an_underwater_canyon.html

    Pythagorus aside, the rule of thumb I keep hearing is seven feet of anchor line for every foot of depth, so at a depth of one mile, a seastead should have a seven mile “clear water” swing radius to allow for changes in current, tides, and even wind..

Viewing 15 posts - 16 through 30 (of 39 total)

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