Difference between revisions of "Mobility"
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The costs of the various options strongly depend on a variety of factors. In shallow coastal waters, anchoring is cheapest by far, and there is relatively little room to drift. | The costs of the various options strongly depend on a variety of factors. In shallow coastal waters, anchoring is cheapest by far, and there is relatively little room to drift. | ||
| − | In the open ocean, anchoring may be prohibitively expensive, and a low-powered system | + | In the open ocean, anchoring may be prohibitively expensive, and in many locations, a low-powered system might suffice to maintain a position with some region. |
Revision as of 01:28, 15 October 2009
Seasteads can be classified by three levels of mobility:
Contents
Fixed
Seasteads which are built on a fixed foundation (sealand), or anchored is a way that is part of the design (Tension Leg Platform). In general, these types of designs are considered neither practical (depth) nor desirable (Dynamic Geography)
Floating
Global position is kept either by virtue of geograpical location (gyre), or by means of anchoring. In case relocation is desired, specialized equipment (tugboats) are hired. Position relative to neighbors is best kept by means of connections between individual seasteads.
Propulsed
The seastead has its own propulsion systems. They should be at least powerful enough to maintain a time-averaged position, and powerful enough to avoid collisions with nearby seasteads. It should be noted that mobility on the water is subject to strong economies of scale (Fuel consumption as function of size) For large seasteads, the cost of fuel is likely to be small compared to other expenses (see: flotel data). For seasteads on the small side of the scale, these figures are probably very different, especially if the design under consideration does not optimize for weight and hull shape, the way boats do. At present, little information is known on the subject; existing data generally does not deal with the hull shapes and low speeds we are interested in; getting good estimates is the subject of present research. To get a rough estimate, the figures in this article are useful. A 3250m3 blunt object is dragged at an estimated speed of 0.5 knots, requiring 12.4HP or ~10kW of electricity input, or 36MJ/h. If said electricity was generated by a diesel generator, that would amount to 3L of diesel an hour at 1/3 efficiency, or two tons of diesel fuel a month.
The displaced volume is in the same range as some of the designs under consideration, which intend to house several families. 0.5 knots might not be enough; finding a place with currents limited to that speed should be possible, but that does not include wind-induced loads, which might be significant.
Overall, it is not certain that continuously propulsed small seasteads will be economically viable, especially given the uncertainty in future fuel prices.
Comparison
The costs of the various options strongly depend on a variety of factors. In shallow coastal waters, anchoring is cheapest by far, and there is relatively little room to drift.
In the open ocean, anchoring may be prohibitively expensive, and in many locations, a low-powered system might suffice to maintain a position with some region.
