The frame in the photos is tied loosely with loops of rope to the bar connecting each pair of spars, such that the spars can easily pivot with respect to the frame.
In the mobile configuration, the sparship totally resembles a pontoon barge, and the blue trayin the photos does not touch the water at all, so we may not really need a real barge. The sparship can be made quite spacious, cheaply, by widely separating the spars.
Some issues : 1) The front spars flooded faster than the rear spars, because of differences in the size of the holes I’d made in them. I did this on purpose so they wouldn’t hit against each other when sinking, but this issue should be easily solved in a real seastead where we can control the rate of flooding.
2) The load wasn’t too well balanced, so the rear spars sunk lower into the water, this will need to be kept in mind (or the front spars may have been scraping against the bottom of the canal where I tried this out, I didn’t get into the water, a bit slimy).
That is totally cool! I have been playing around with variations of the design in my mind…
One concept I have is to have free floating barges and spars. The barge and spars are towed out to deeper water. The spars are towed in a horizontal configuration. The spars are flooded until just their tops are sticking out of the water. Each spar is attached to the side of the barge. Compressed air is used to push water out of the each spar to elevate the whole platform.
The barge and spars can be built independently. Indeed, they can be built at diffferent locations. There is no rotating joint to engineer. The barge can be build out of light materials to save weight. The spars can be built out of simple ferro-concrete (cheap!)
” For instance how large must it be in order to raise far enough above the sea?”
I’ve been thinking about that myself…the answer depends on numbers such as weight of barge, height desired above sea level, details of the design etc. Can’t give any reliable numbers, but I think the spars may have to be about 100 meters or so? But we’ll have to do a rigorous analysis with hard numbers before that answer is clear…
” Would it be possible do do away with the ballast if the spars are spaced far apart enough to keep it upright that way?”
Yes, then you get Vince’s Water Walker. It’s doable, but I’m doubtful about having all our buoyancy on the surface, that’ll make the structure sensitive to wave action. Spars provide a small area for wave impact, so might be more suitable IMO.