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Conflicting design goals regarding movement

Home Forums Archive TSI Engineering Conflicting design goals regarding movement

This topic contains 14 replies, has 10 voices, and was last updated by Avatar of J.L.-Frusha J.L.-Frusha 4 years, 3 months ago.

Viewing 15 posts - 1 through 15 (of 15 total)
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  • #814
    Avatar of Jeff-Chan
    Jeff-Chan
    Participant

    One of the concerns about the first MI&T design is the diesel fuel burn rate. In taking a step back from the problem, it seems that we have some conflicting design goals:

    1. Seasteads are supposed to be mostly stationary. Having a city at sea to me means it would generally be in a stable location or at least not move around very much. For example, being able to tap into Silicon Valley resources would imply staying relatively near that area.

    2. The current design is apparently intended to migrate slowly between California and Hawaii or California and Mexico.

    These seem like contradictory goals. The fuel burn rate might be much lower if the goal is not to migrate over thousands of miles, but to stay relatively stationary. Naturally if you want to be stationary, you’d also chose a spot that didn’t have big currents.

    The spar design is potentially very good for stability in waves, but suboptimal for movement. A ship is better if mobility is wanted.

    I’m wondering if we can save fuel burn if we don’t want to cruise so far.

    Taking another step back, what is the goal of migrating between Mexico, California, Hawaii? What’s the benefit? Why are we wanting to do it instead of staying more or less within relatively easy reach of say San Francisco, Los Angeles or San Diego?

    An opposite approach would be be in the gulf stream or some other large ocean current, and just use stationkeeping to stay within the current. That would get you lots of mobility to be constantly traversing oceans, but doing so working *with* nature instead of against it. OTOH the currents may not go exactly where we want to go in terms of good weather, favorable locations, etc.

    Another approach would be to use sails or kites to utilize the wind to move. The stead would have some wind drag regardless, so the wind would be trying to move it even without sales or kites. The engines would need to try to counteract that, and require fuel to do so. As the othre thread mentions, countervaling sea currents and wind could be used to move in any direction (without using fuel).

    Anyway, wanted to offer a sanity check on what appear to be contradictory goals: mobility versus stationary cities at sea.

    #4917
    Avatar of Wayne-Gramlich
    Wayne-Gramlich
    Participant

    The Hawaii to SF migratory route is basically on hold. This migratory concept came from some ideas proposed by Vince in the Atlantic ocean. (I can’t find the reference right now.) One problem with the migration is that it complicates the logistics of moving people and supplies to and from the seastead.

    The current thought is that ClubStead will tend to live off the west coast. It may migrate north during the winter, but it will tend to stay south during the winter. The more likely scenerio is that it will mostly stay south. The coast off of San Diego is looking pretty good.

    With a stationary platform, a mooring system can be considered. Mooring systems for ClubStead sized structures cost millions of dollars. In addition, they need a license from the nation that controls the EEZ. A system that uses propulsion needs no such license, but consumes energy. It is a trade-off.

    We are still trying to get a handle on what station keeping costs are going to be.

    #4918
    Avatar of vincecate
    vincecate
    Participant

    Wayne wrote:

    The Hawaii to SF migratory route is basically on hold. This migratory concept came from some ideas proposed by Vince in the Atlantic ocean. (I can’t find the reference right now.) One problem with the migration is that it complicates the logistics of moving people and supplies to and from the seastead.

    A single family seastead migrating between lots of islands makes life on the seastead more interesting. The seastead can get into a harbor or the downwind side of the island where a dingy can make it to shore. So it is really similar to how families travel in sailboats now. With a kite pulling the single family seastead and a course that is mostly downwind, there is not a problem of using up lots of fuel. This is why I am using a kite to pull me on my seastead model.

    For a single family seastead going to a port frequently makes the logistics of getting supplies easy.

    You could stop at a dozen locations around the North Atlantic spread around through the year. Much more interesting than just 2 stops. Also, the North Atlantic migration makes a big difference in terms of the maximum size wave you would have to deal with.

    When there are enough people that life in the floatilla is interesting enough, going ashore often will not be so important. Many people find an island with 12,000 people too small, so living on a seastead without visiting other places often will not work for many people. Many nerds could spend all their time surfing the web, but wives often want a variety of shopping possibilities.

    http://wiki.seasteading.org/index.php/User:Vincecate/Migration

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2

    #4920
    Avatar of livefreeortry
    livefreeortry
    Participant

    The migratory life appeals to me too. As long as we have good internet connectivity, and depending on whether our economic situation requires frequent land-trips, I’d totally like to live in pleasant weather all year.

    Vince, is it true that max wave height is lower in the north atlantic compared to the pacific, as you seem to imply? What about hurricane season though?

    Regarding Clubstead, as I see it, the clubstead is a project to be considered at a stage when seasteading is a well established concept. We need to start small. Clubstead is too reminiscent of other projects like freeom ship etc. Is TSI planning to start R&D on single family structures sometime?

    In the context of mobility vs stability, what are people’s thoughts about the feasibility of a variable geometry seastead? http://seasteading.org/interact/forums/engineering/structure-designs/sparship-2-h-configuration This is a potential solution I’m quite optimistic about. Another possibility is a SWATH type structure, which might provide stability as well as mobility.

    #4921
    Avatar of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    on the subject. If seasteads are migratory then the spar wont work, because of its design. Now, w/a proper design, lets say a boat shape type, you will encounter high cost of fuel. Just an example, an 80 H.P. Ford-Lehman diesel engine will move a 30 to(max) 35 foot powerboat @ 5-6 knots burning 2-3 gal of diesel an hour.You do the math. If the seastead is big enough, lets say for 200 people, or more, than the costs are less because we split the cost of fuel and also it cost less fuel to move the seasted. In many terms,the bigger the better, in this case, not only fuel wise but also in terms of seaworthiness and as to the social aspect too. Now, if stationary, anchored or moored, regardless of size(in this case the bigger the worst), you will encounter lots of problems w/the authoritiesof the territorial waters you are in.(Sadlly U.S. are among the worst).Outside the 12 nm, even inside EEZ its not bad,because you can anchor anywhere,but you cant secure permanently on the bottom(you will be an island then,…a no no). Sooooooo,..the only conclusion here is to buid big,put out to sea, and find a shoal outside EEZ’s were you can drop the hook or secure on the bottom. There are some out there, all around the world, worth checking (I used Google Earth and find a few).

    #4922
    Avatar of Jeff-Chan
    Jeff-Chan
    Participant

    Hi Vince, can you go upwind with a kite, maybe with tacking as with sailing? If so then kites from clubstead may be a viable way to do station-keeping. Large kites are being tried on big commercial cargo ships, so they may have some real-world viability and experience for motive force.

    Hi Wayne, Vince’s migration idea was based on mostly currents or wind, I think, which would seem to be a very different (lower) fuel consumption mode than powering along on diesel. You could use the engines to stay within a current, which again is relatively low-fuel-consumption.

    That said I’m glad the idea of migration is being backed away from for clubstead. I agree it’s more practical to stay near a land-based large city at an early stage fo seasteading. Staying relatively stationary will make logistics like resupply simpler, and cut fuel costs over migration. Also as I and Oceanopolis mention, spars aren’t really meant to be very mobile. There’s lots more hull drag than a ship form.

    That said, there’s definitely a role for migration in different contexts, for example as Vince supposes if the community is either very small like a family unit, or very large like its own floating city.

    My advice is to chose modes appropriately for the circumstances. For an initial clubstead drawing customers from existing land cities, non-migration or limited-migration may be more appropriate.

    #4924
    Avatar of vincecate
    vincecate
    Participant

    The migratory life appeals to me too. As long as we have good internet connectivity, and depending on whether our economic situation requires frequent land-trips, I’d totally like to live in pleasant weather all year.

    Vince, is it true that max wave height is lower in the north atlantic compared to the pacific, as you seem to imply? What about hurricane season though?

    I think that my migratory route has a much smaller 100-year wave than just staying 200 miles off California does. The hurricane season is sort of late summer and for this the route is North-East and far from the hurricanes. The storm season in the North atlantic is in the winter and for this the route is toward the Caribbean. So I think it really does avoid the big waves well. It would be good to have an expert figure out what a 100-year wave value is for a migratory route like mine.

    http://wiki.seasteading.org/index.php/User:Vincecate/Migration

    #4923
    Avatar of vincecate
    vincecate
    Participant

    Jeff wrote:

    Hi Vince, can you go upwind with a kite, maybe with tacking as with sailing? If so then kites from clubstead may be a viable way to do station-keeping. Large kites are being tried on big commercial cargo ships, so they may have some real-world viability and experience for motive force.

    Kite surfers go upwind all the time. You do need to tack back and forth as with sailing. I have done it with a small sailboat and a kite (mast off). Plenty of other people have done it too.

    You need a shape that can move forward through the water easily but resists moving sideways through the water. So a sailboat with a keel is good.

    It would be possible to replace the 3 balls on a waterwalker with 3 sailboat like shapes and then be able to tack and go upwind.

    It would never work with spars. Clubstead has no chance of using kites to go upwind.

    But with my route your would be going downwind or a bit left or right of downwind nearly all the time. So a multi-string kite can do this. Only near harbors would you need to go upwind and using a motor for short distances would not be too costly.

    The other problem though is that clubstead is so deep it could not get close enough to many islands to make using a small boat easy for going to shore. If you are trying to get visitors for 1 week at a time, then being on a yearly migration is trouble for getting visitors on and off as you are at a different location each week. But for a family that is ok. So migration and clubstead just don’t seem to go together for many reasons.

    But single family seasteads and migration seem to work fine together.

    #5139
    Avatar of icetemp
    icetemp
    Participant

    To throw my 2 cents in…migration has more issues than just the cost of fuel. If you are moving something big enough to provide perminent habitation for in excess of 200 people, it is going to fall in the 500 GRT (Gross Register Tonage) classification. The license for that is more than just a bureaucratic paper. The skill level just to be safe takes years. I know, I have a “Any Tonage, Any Ocean” Masters cert. And the salary cost for these people exceeds the fuel cost. Unless you want to end up hiring a 20 man creww, with a salary plus overhead of nearly 2 mill a year, stay stationary.

    #5140
    Avatar of DM8954
    DM8954
    Participant

    Awww, can’t you just vollunteer to drive for us? Once there are multiple seasteads someone will chauffeur you between ‘steads on a speedboat and treat you nice & stuff.

    An argument I half-expect someone to throw out there is that we don’t have to obey laws in international waters… even though that’s not entirely true, especially in the early years, you’d still end up leaving international waters over the course of a migration.

    Fortunately, I think the main advocates for migration are also advocates for smaller-size seasteads.

    Thanks for the information, icetemp!

    #5962
    Avatar of jcrawford
    jcrawford
    Participant

    I think that migration is definitely a good idea. Life on single-family seasteads could quickly become boring, so at least early on visits to mainland would be a must. It’d be more interesting if you could visit different mainlands.

    The spar design definitely eliminates the possibility of travelling against the wind on wind power, as spars have little to no ability to resist being pulled sideways. This is another plus to repurposing boats or building boat-like seasteads.

    #8572
    Avatar of billswift
    billswift
    Participant

    >we don’t have to obey laws in international waters

    Sorry, but there are international laws you must obey. Any non-flagged vessel is illegal and can be boarded and its crew taken into custody by any nation’s vessels. I don’t know about you, but building an illegal seastead strikes me as an excessively expensive way to go to jail. Any vessel that is flagged, must conform to the laws of the flagging country, but you can shop around for a set of laws that is more comfortable for your situation.

    The problem of certification is another good reason for multiple smaller structures for a seastead community.

    I think the best solution, except for those that need to stay near a city for economic reasons, is a community of smaller specialized seasteads that work together and basically float freely, most likely circling a gyre, with just enough mobility to stay together and to keep from floating out of the gyre. There are five large gyres – the most famous is the Sargasso Sea in the North Atlantic, one in the South Atlantic, one in the Indian Ocean, two in the North Pacific , and one very large one in the South Pacific (interestingly, from what I can see right now, most of them are fairly warm waters, except the South Pacific gyre which is fed from the Peru Current which comes up from the Antarctic).

    #8574
    Avatar of billswift
    billswift
    Participant

    The biggest problem of a free floating seastead as opposed to an anchored one is the reduced ability to draw energy from currents or winds. Current energy is completely out since you are floating along with the current. Less obvious is the reduction of available wind energy, since surface currents generally follow the prevailing winds. There will often be enough difference in wind speed that you can get some benefit from it, but it will be reduced.

    #9102
    Avatar of J.L.-Frusha
    J.L.-Frusha
    Participant

    While drifting is not as eficient as being anchored, for generating energy from the currents, the current is still moving faster than the floating object. To see this, go out on a river in a boat (canoe?). Watch the water for floating objects(leaves work). Your vessel will not reach the same velocity as smaller, less resistant objects. IAt the same time, the blades of the generator are acting as a sea-anchor, to pull you faster than you would go without them in the current. If the intent is to drift/migrate with the current, the generator blades are a plus, at the cost of generating less electricity or mechanical energy. At least 2 forces are at work, to let the current move faster: Drag and Inertia.

    Being anchored, there is a greater velocity difference to work with(in the same current), for extracting the energy(electricity generation/mechanical energy) from the currents.

    Pick and choose what you, as an individual, want to do. Make, or choose, your Seastead with that in mind. What is best, for what you/your group plan to accomplish. Need more electricity? Park it! Drop anchor as possible. Decide to move? Go with the current even though it reduces the energy available to extract from the current.

    #9103
    Avatar of J.L.-Frusha
    J.L.-Frusha
    Participant

    Structurally, the floatation method calls for both the ability to support all potential loads and still clear the sea floor, wherever you go. The deep cylinders will add drag, one way or the other. If you are drifting with the currents and only using power to guide the thing, the fuel cost is much lower than pushing it where you want to go, if you use the currents that are available.

    Most of the currents are circular in nature, to get to a Northerly position, in a South-bound current, you have 3 choices: Stay with the current until it circles to where you are going, fight the current to get there, or cut across the middle of the circle, to the opposite(North-bound) side of the circular flow.

    You have to chart the course based on the clearance you need, for the sea floor.

    It is harder to push or pull a heavy and draggy shape, but it may not be as necessary as it seems. For the most part, station-keeping thrusters can also guide the Seastead, when using the currents to move to another location. Just stay in areas where depth is not an issue, to keep from running aground.

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