Spring is sprung, and with that young hearts turn to thoughts of camping & beer.
This floating campsite could at first glance easily be thought a raft or a floating house, but there's some rather important differences. For one thing it's not a raft or a floating house.
It's a near-hemispherical bowl, say 40m across, lined (not filled but lined) with earth, grass, trees, etc, most happily flourishing at technically well below sea-level. In the middle at the very bottom of the bowl is a cottage... or at least a decent spot to park a tent.
It floats in a lake or other freshwater body of water. Waterskiing isn't much of an option; rather the electric outboard motor slowly propels it, at a walking pace, out from shore, away from the noissome throng, for the weekend or however long it takes to unwind.
Fish from the side, fly a kite, build a campfire.-- FlyingToaster, May 20 2012 … but whatever you do, don't dig a latrine.
[+]-- 8th of 7, May 20 2012 If it's a bowl filled with turf, upon which grows grass and trees, which means that the turf has its own water table... how does it maintain buoyancy?
Shirley it will displace more than the volume of its solid contents. Is it high-sided? Is there some manner of pump to prevent swamping?-- Alterother, May 20 2012 It's not a particularly shallow bowl. I've stipulated "fresh water" to avoid swamping issues in the smaller lakes, though I suppose a bilge pump wouldn't be out of order: it could be used to infuse water as well, during a dry summer.
It doesn't have to protrude out of the water any more than to avoid wave height plus a safety factor, so... 10 ft ?
For a 40m bowl (120ft dia) I'm picturing an average of 5-10ft deep of soil, rock or structure: a bit more in the middle where the taller trees are, much less near the top edge which would be mostly rock glued to the side.
An hemisphere with a 2m granite shell(which we'll use to approximate the weight of the bowl and landscaping) will displace about 2/3 of its volume of water. Of course a complete hemisphere is a bit extreme: you probably don't want to have to rappel to and from the edge .-- FlyingToaster, May 20 2012 //whole-hog...artificial island//
There's *way* more bacon in this idea than an "artifical island".
An artificial island is buoyed up by a lighter-than-water substructure which requires a containment structure. In order to keep the island from buckling with the waves, even more substructure is needed to keep it from falling apart.
The campsite, being bowl-shaped, supports itself.
boat vs. raft.-- FlyingToaster, May 20 2012 //don't dig a latrine// why not ? You'd probably want to put a bit of thought into where to put the picnic blanket for the next couple weeks, but apart from that, <shrug>. But it'd be designed with a small efficient innocuous recycling/disposal system and/or a shed with a crescent moon cut into the door.-- FlyingToaster, May 20 2012 We foresee stability issues, unless you ballast the centre of the base substantially.-- 8th of 7, May 20 2012 ^Round bottomed boats are typically known for balance issues, but we're talking about a 120ft wide bowl, say 40-50 ft deep, rising 10ft above the water. But most of the weight is centered anyways: that's where you want the tallest trees, so that's where the ground is deepest to handle the root system.
The spheric sectional shape has the advantage of minimal surface area, to provide strength.
On the other hand feel free to suspend a multi-tonne iron ball from a chain attached to the bottom center, into the lake. § x1-- FlyingToaster, May 20 2012 //the tallest trees //
But their centre of mass is going to be part-way up the trunk, not down in the base. That may bias your calculations.
Since the bowl is, inter alia, impermeable, water will accumulate at the base and might "drown" tree roots. So maybe a small pond in the centre to act as a sump ?
The Big Iron Ball idea has considerable merit.-- 8th of 7, May 20 2012 I was thinking more the mass of the ground (sp.gr 2+) rather than the trees (sp.gr <1).
The skin of the bowl would extrude contours to the interior, passively designed to hold water at certain levels, to mitigate somewhat the tendency to form a lake at the bottom after a heavy rainfall.
As [Ao] points out, a bilge pump would come in handy just in case, and reversible to water areas during a drought.
//a small pond// definitely: maybe a small raft in the pond too :)
//If it's a bowl filled with turf// not filled so much as *lined* with turf and other landscaping elements. The ground might be 10 feet deep in the middle at the bottom.-- FlyingToaster, May 20 2012 //Oceanic Garden// I don't know what that is...
More like a small green valley floating in a lake, or a sinkhole garden (but the sides not as steep).
Take a honeydew melon, chop it in two and, from half, scoop out all the seeds and most of the pulp 'til you're left with just the skin and say half an inch of pulp lining it. Something like that.-- FlyingToaster, May 20 2012 But won't that attract flies ... ?-- 8th of 7, May 20 2012 I wouldn't fit so well in the melonisland, but I like the main idea.-- blissmiss, May 20 2012 Could this be implemented with a lemon rather than a melon ? Sharper, more acidic, with a waxy exterior ?
Then you could make The Mother Of All Gin And Tonics ...-- 8th of 7, May 20 2012 ah right then Mr.Borg, you'll be wanting the usual modifications ? Interlocking clamshell conservatory roof that stows underneath when opened, wrought-iron railings, crushed marble pathways, twin 40mm Bofors on a tower, at the spheric centre, next to the Zeppelin mooring...
[21Q] ah got it; I like that one <link>. If you replace the decommisioned ship with a bowl shaped vessel (maximum strength per weight, no need to be streamlined), then might be rather similar'ish in form if not intent.-- FlyingToaster, May 20 2012 marked for tagline: "The Mother Of All Gin And Tonics "-- normzone, May 21 2012 // 120ft wide bowl, say 40-50 ft deep, rising 10ft above the water. //
We're talking about one hell of a lake to float this thing in. 30-40 feet of draft? There are some deepwater shipping ports that don't clear that. In most large lakes, you'll be hard-pressed to find a spot deep enough to moor it, much less manuever it. How you'd ever get it launched in the first place is beyond me, unless you constructed the hull on shore, launched it empty, floated it out to the mooring, and then brought all the ingredients out separately. That might be workable.
Hang on.-- Alterother, May 21 2012 Lake Baikal would be suitable... as would Victoria, Tanganyika and maybe a few others.-- UnaBubba, May 21 2012 Okay, so a stainless steel bowl 120' in dia and 40' deep with a hull thickness of 1/4" (I could have built it with 3/16" but it's a deceptively tricky shape, structurally speaking), plus internal gusseting and miscellaneous plumbing, is going to weigh in at roughly 23 tons and will draft less than 3' of water when empty. So launching empty and towing into place is doable.
The next step is probably to put about 5' or so of concrete into the bottom to act as ballast, but it occurs to me that if you are going to create what is essentially a semi- isolated ecosystem, you could just fill it with gravel instead and let the water table itself serve that role. Naturally, the interior of the hull will require sealing in order to keep the stainless out of contact with organic compounds, else it will degrade the crystal lattice and rust from the inside. A thick layer of PTFE should do the job.
After that, you bring in the landscapers to arrange the soil strata, plant the trees and bushes and lay down sod. A large false boulder should suffice to conceal the environmental controls, maintaining the illusion of pastoral bliss in a giant salad bowl--although you will occasionally hear a low hum when the pump kicks on in the middle of the night.
On the whole, the idea is not impossible, but simply buying a pre-existing natural island would be much cheaper and only a little less mobile.
[+] for forcing me to do math.-- Alterother, May 21 2012 But it would still be cheaper than anything else that floats having that much square footage of living space.
Islands aren't always available for purchase, nor conveniently located at the right price.-- FlyingToaster, May 21 2012 Use vermiculite in place of soil, and a geotextile blanket impregnated with polyamide crystals to hold in place the water for the greenstock. That will cut the mass considerably, and largely prevent unplanned weight shifts.-- UnaBubba, May 21 2012 I like it. I'm not much of a landscaper. I'll do the hull (already built it in my head), but the rest was just speculation.-- Alterother, May 21 2012 //weight shifts// not too much of a worry: the target body of water is medium-sized lakes (ie: you can't see the other side, but not the Great Lakes: do that and you might as well call it 'Atlantis') so there would be next-to-nothing in the way of bobbing or shifting. The electric drive (say one of those tugboat thrusters) would be slightly vertically adjustable to account for any CG/CD differences while in transit.
The only potential weight shift would be if it ran into a sand bar at full speed (2 mph). I guess some landscaping designs could be compromised.
//mass// [Ao]'s shell puts it at 1m displacement. There's enough buoyancy left over to coat the entire inside in granite over 2m thick and still have it poke 3m above the waterline. Mass is only a concern for acceleration and deceleration maneuvers which it won't be spending much time doing. Weight is also a good thing in respect that it offsets the external water-pressure on the hull.
//speculation// well... on the shell would be any scaffolding to hold features in place where necessary, retaining walls for rainwater retention, water distribution/bilge-pump piping.
On top of that the actual landscaping. My own personal model would have a bit of unobtrusive terracing, maybe a shallow cave system on one side, but would mostly look like and be a simple lightly-rockwalled well-treed crater as found in the middle of any forest, with a pond off-center at the bottom. Equipped with a raccoonapult.-- FlyingToaster, May 21 2012 If you are only in shallow lakes you wouldn't even need a motor but could move it from place to place with a long pole. Then call it Pole-land. (Sorry, I just took a punt)-- AusCan531, May 21 2012 I'd complain about you just barging in with that but I'm still trying to figger out where to put the windmill and tulips to justify the post title.-- FlyingToaster, May 21 2012 I was thinking of wind (You've heard of it, right?), rocking the island... then you get weight shifts and shit and it ends up with a capsize incident and missing passengers and lawsuits and public ridicule because you, as captain, end up communicating in Italian with emergency services personnel and pretending you can't see what's happening. That sort of thing.-- UnaBubba, May 21 2012 Like anything else you could thrash it on purpose, if there existed an artificial wind machine big enough (which there isn't). For even abnormally high natural winds, the fact that most of the weight and surface area is under water would mitigate the effects; any chance resonance wouldn't last long enough to actually get it to wobble in a creative fashion. The shell would also certainly survive migrant tornado damage much more than any other boat. The trees inside the shell, well that'd be something else I imagine: yes they'd be somewhat more prone to falling over than trees in a natural valley, but not much more. Bear in mind that on top of the shell, as previously mentioned, are structural retaining walls (not of the ornamental brick type, but of the solid steel, welded to the shell type) to hold some terracing in place (and retain water for the plants on the terraces).
Passengers abandoning ship can either use the boarding gangway, raccoonapult, or just sit in the rowboat in the pond in the valley in the lake and wait.-- FlyingToaster, May 21 2012 What about pirates?-- Phrontistery, May 21 2012 They have to bring their own beer and nachos.-- FlyingToaster, May 21 2012 I just don't know why you're so worried about it tipping over... What's the max, shit-hits-the-fan wave height you're expecting? 2m or so? Something 40m across should be able to handle that easily, if it's remotely stable.
An optimally stable shape might be a torus with central keel/counterweight, easily fabricated out of steel. I'm thinking maybe 3 metre diameter tube perimeter - giving approx 800 Tonnes total displacement, just from the perimeter.
What would be better is an island with a perimeter beach all around, that can be raised out of the water for transit by evacuating ballast tanks.-- Custardguts, May 21 2012 I don't care how much they're offset from the hull; I don't want a ring of Bangalore torpedos around the rim.-- FlyingToaster, May 22 2012 eh ? Which is supposed to be which. I know what a B T is.-- FlyingToaster, May 22 2012 det cord in a thin pipe iirc (or just detcord?); maybe something more along the lines of parrot repellant, termites for the wooden legs, or a strong electromagnet that sticks their hooks to the edge.-- FlyingToaster, May 22 2012 random, halfbakery