Forum Replies Created
March 31, 2010 at 12:34 am #9951Gentry wrote:
I noticed that you’re severely under-budgeting for food. (Not that it’s a great concern since it only makes for a small part of the total expense)
I agree. I updated the $800/person to $2500 per person and changed the link.
In the early days when there are few other seasteads, I expect to make frequent stops at ports and also to be fishing all the time. So the food storage is for some survival mode really. Fishermen, even here in Anguilla, put floating things into the ocean to attract fish. A slow moving seastead should do this very well. So I think fishing will be rather easy.
— VinceMarch 25, 2010 at 10:32 pm #9933J.L.Frusha wrote:
FLIP gets anchored with 3 deep-sea anchors, to stop the motion that would interfere with the measurements… Since then, the anchoring has been modified, using nylon ropes attached tobetween the anchor-chains and FLIP. I’ve done that research, so I know what I’m talking about, there. Yes, FLIP is anchored against a certain amount of buoyancy, to remain stable, the same as oil-rigs. It’s easy enough to find on their websites…
Having some extra buoyancy so that you can lift your anchor is not the same as having a tight non-stretching line going straight vertically down to the bottom so waves can not lift you up. If it is so easy to find, please post the the URL to what you found that makes you think it is like an oil platform “tension leg” system. I do not believe it.March 21, 2010 at 2:30 am #9905J.L.Frusha wrote:
All they had to do was cut the anchors and float away… Being tied to the bottom, the FLIP didn’t rise with the swells, so the waves won that battle, due to human stupidity.
The reason FLIP did not rise with the swells is it has a small-waterline-area. It is a spar. This is the point of a spar. It is not tied to the bottom in such a way as to keep it from floating up and down.
If you want to go up and down in sync/phase with each wave you need something with a larger waterline area, like a boat.
Look at the simulation of the TSI design, which has a small-waterline-area. The structure is going up and down, but not with the waves. So it can be down when the waves are up.
Most floating oil platforms are tied to the bottom so they don’t bob up and down and have the problem of going down when the wave is up. This is called a “tension leg platform”.March 15, 2010 at 6:34 am #9859
There are several very different ideas about what seasteads should be. They do not all look like oil platforms or hotels.
There is at least some interest in self sufficient seasteads:March 15, 2010 at 5:48 am #9858xiagos wrote:
How have your experiments gone since 2008?
If you put a floor on the tension circle you are a boat at that point. It would be far more expensive to build. If you want to be in international waters, then using lines to the bottom to stop up/down motion is also really expensive.
I have tested many other models:
My latest experiment and thinking:
– VinceMarch 10, 2010 at 2:45 pm #9803
Here is another model of mine that does a good job of demonstrating the heave problem:
This bobbing is out of phase with the main wave period. When it is very low the waves are high and when it is high the waves are low. All the motion is driven by the waves (moslty bobbing/heave).March 10, 2010 at 2:24 pm #9802
Here is a video of a seastead model bobbing up and down in the waves:
I am the guy in the water with the waterproof camera on a stabilizing device. All the videos of seastead models tested in waves that have been posted in the first 2 years of seasteading.org’s existance were done by me (more than 20 videos). It foolish for a guy who joined 2 weeks ago to be calling me a “dunce” when I say that bobbing up and down can be an issue.
— VinceMarch 9, 2010 at 11:56 pm #9801
You found a graph showing that two waves of the same magnitude and “180 degrees out of phase” add to zero, so now you think that if a floating platform is 15 feet up when the ocean wave is 15 feet down that it is the same as if there was no wave? Really?March 9, 2010 at 11:46 am #9788vincecate wrote:
Since it does not do this in phase with the waves this is a problem. Any design with a small waterline area has this issue.
The whole point of small waterline area is to not go up and down with each wave that passes. But each wave does have some influence, even if smaller. And if a series of waves of the wrong frequency come by their cumulative smaller influence can get the structure bobbing up and down, unless steps are taken to deal with this issue.
So if it takes your structure 10 seconds to bob up and down once and the waves are coming about every 10 seconds, then the bob can get worse and worse, unless you have something to dampen out the heave.
– VinceMarch 9, 2010 at 11:20 am #9787
Have any links? I can’t find anything on this “movement can get out of phase with the waves” thing
“Heave” is where the whole platform goes up and down. Since it does not do this in phase with the waves this is a problem. Any design with a small waterline area has this issue. You can just search google for “heave platform”.
— VinceMarch 9, 2010 at 10:41 am #9786wesley_Bruce wrote:
Not with active computer controlled suspension and wave prediction system. Sure you need backups on your backups but that’s be my point of the post. Active suspension systems have been around for cars, trucks and even trains for a few years. We now know that they can be programmed to handle complex wave states at relatively high frequencies, rutted roads and slippery surfaces. Wave frequency is lower giving interesting options. Active damping of buildings in high winds and earth quakes are also working out. In this case they use tuned mass dampers and sliding foundations.
Getting out of phase with the waves is a real problem for a dumb mechanical system but add an active system and you can adjust.
I agree that active controls are very interesting. Designing it so that when parts fail you are not at risk becomes really important. In practice I think computer controlled stabilization is too dangerous or costly for early seasteads. In the long term it could well be the way to go.
I have seriously thought about suspending my 26 foot boat below a tri-pod WaterWalker with some system to dampen out movement.
For this design http://wiki.seasteading.org/index.php/User:Vincecate/FloatingVilla I think that some big stabilizers similar to http://www.boatstabilizers.net/ hanging from each of the 3 legs would work well. With those you could make the floats more spar shaped and not get out of phase. If those stabilizers fail, the seastead moves a bit more with the waves in that corner but does not become unsafe if they are not too long and skinny. I would want a design like that, where stabilizers failing does not make you unsafe.
If the floats are wider in the middle, not just a smooth pole, then up/down motion can make a wave and get rid of energy. This will reduce the possibility of getting way out of phase.
When I imagine my family moving onto a very early seastead, having critical computer controlled things that can put my family at risk if they fail seems really bad. I think I can get enough stability without it.
– VinceMarch 8, 2010 at 10:40 am #9766
I was thinking about someing like the SWATH for platforms.
small waterplane area submeged hull maybe.
This is called a Semi-submersible. It is the most common type of floating oil platform but is usually tied to the ocean floor. If it is not its movement can get out of phase with the waves and run into trouble. Does not seem possible to make a small one that works. If you think otherwise try building some models and testing them in real waves.March 7, 2010 at 11:53 pm #9757wesley_Bruce wrote:
We probably need to take a look at WAM-V again.
Yes, it is interesting. I too think that in mass production it could be in the million dollar range. Engines could be smaller and cheaper. With 4 days warning and 10 MPH you can get about 1000 miles to the side of a hurricane path., so that is plenty of speed to avoid storms. I imagine a lightweight structure could be attached to the top that gave more living space.
I have yet to see video of it on 8 or 10 foot waves, though they say they have gone on 1000 mile trips, so they probably have been on real waves. But I would be more comfortable that it was really ready for open ocean if they were showing it on big waves.
My guess is that with station keeping that kept it pointed into the major waves it would be ok to work or sleep on.
One of the wam-v videos has a guy who says he is working on a second version. The first seemed rather good and the second version should be even better.
This thread was titled smallest individual structure that can survive in the deep ocean. But what I really want is the cheapest for a family that is still safe and comfortable. This is a contender. We have 10 example designs for single family seasteads. I think out of those “big enough for a family but probably under $2 mil”, that the WAM-V is the most real.
They seem to be in the Bay Area, maybe someone should try to check them out.
— VinceFebruary 2, 2010 at 2:38 am #9454Eelco wrote:
Possibily. But will be hard to beat boats on their own turf (same area of design-space). The thing with short spars; how is that qualitatively different from a semi-sub?
A little thing called “affordability”. A tripod with spars floating up from the corners is a tensegrity design that is very wide for the price. So it is much like a semisub in wave response but much lower cost. Also, that the idividual floats can move sideways as the wave goes past is different.
Boat designers have not focused on the goals of seasteaders. The design space is different than the existing products even if it is still a boat.; It is like saying, “we have had boats for thousands of years, an airboat that goes through swamps at high speed is nothing new”. Or saying that, “FLIP is just another boat”. It is still a boat, but not like previous boats.February 1, 2010 at 3:56 am #9444Melllvar wrote:
Attaching a pressure chamber to whatever structure and sinking it to a safe level when the conditions get to be more than whatever your structure was designed for seems like the safest solution (or just make the whole structure a sub).
If you have a pressure chamber strong enough that it could be underwater 100 feet, then it would never be hurt by waves on the surface. You could drop a weight down on a cable and have the “ballhouse with hanging ballast” idea that works amazingly well. And I would feel safer at the surface than down below, even if we were going up and down 50 feet in 50 foot waves. Check out the video with the long hanging ballast:
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