What is the definitive test? I dunno. I guess the claim is that you can slide the weight horizontally off the top, and the system will still reset just as normal. Then you can slide another weight onto it at the bottom, stroke, then slide that weight horizontally off the top. Repeat until all your weights is lifted, for free. Then you can drop those lifted weights with a cuckoo clock mechanism and extract useful energy as they slowly fall. As much as you like, since you lifted so many weights for free.

Correct me if I'm wrong here ...

1. You know what the minimum head height is in the outermost channel so that the Pod/Riser plus lifted mass is just floating.

2. You know how much extra volume & weight of water must be added to the outer channel so that the Pod/Riser plus lifted mass will stroke the full 10 mm after release.

3. You know the mass/weight of the lifted mass.

4. You can calculate how much PE in Joules is given to the lifted mass after a 10 mm stroke length.

5. You can see what the new head height is to achieve this & calculate the PE Joules of lifting the additional volume & weight of water that was given by you so that a half cycle stroke to do Work could be had.

6. You can compare the two results.

N.B.1. I am assuming we can forget about other water columns & air columns jockying for position in transition up or down.

N.B.2 I am assuming that once the lift mass is laterally removed that the system returns to start conditions of its own volition, or at least, with no additional Work Done by you, no matter how long that takes.

Does that sound reasonable or have I forgotten something ?

Often a stepped diagram helps visualize the flow system to find other parameters that might be consequential.

JMO's.

P.S. you have to make some adjustments in calc's second part of cycle to allow for the final position of the Pod/Riser without lifted mass [it probably won't sink so low] because the lifted mass is going to find its own way home & not hitch a ride.

Then you have to think about what is required to get the Pod/Riser to the start height so the lifted mass can slide laterally on top for another boost upwards etc e.g. it might stop part way down, let the lifted mass slide on top, then settle to original start position with everything in equilibrium again.

Yes, you seem to have forgotten the automagic bollard. It has a heavy mass of perhaps fifty kilos and is raised up a full meter, by the gentle application of a few tens of grams of upwards force over the same distance. Then it's latched in the raised position. When it's time to lower it you just unlatch it and it descends... slowly and gently.... back into its hole. If you simply compute the increase in PE based on the mass of the bollard and the distance it was raised, and compare that to the force you applied over that same distance to raise it.... what will your result show? A massive advantage, which, if you didn't know there was a preloaded spring and a gas piston in there making the bollard "just barely not float", you might think it was an overunity bollard. And since the spring cycle is fully reversible with negligible losses, you could stand there all day long, raising and lowering the heavy bollard and never break a sweat. And I'd be very amused seeing you doing it, working out your OU automagic bollard cycle.

So, since the system has to be precharged to the point where the moving parts are actually floating but restrained from moving upwards...... and since that precharge is apparently conserved just like the preloaded spring in the bollard ....... it becomes a bit more difficult to compare the input work to the output work... because the TRUE output work is much less than it appears to be, since most of it is being done in a reversible manner by the spring preload.

I for one do not believe in the "sliding over off the riser" of the lifted mass, to make its own way home, because of the reductio ad absurdum I have tried to illustrate. If you can do that, you have _infinite_ OU, because you do not need to use the same weight.... you can wind up with all the weight in the world, lifted up onto your platform, by your "free" and reversible input work cycle. This is not allowed in my reality, sorry, therefore the idea that this is possible is flawed.

Not much of a weekend update I'm afraid.
Some unusually nice weather shifted priorities to fall cleanup.

But here's an updated picture of the model showing this week's changes.
- Full floating POD replaced by a sealed "riser" - 4.5"OD
- Pre-load and lift weights relocated to under the bench, much more stable!
- Bottom ports added, using a squeeze bottle to adjust works great. ( figuring out WHAT to adjust is another matter.... )

I can still only get to 43" head locked down and shooting for "IDEAL", I'd be happier if I could get the setup up to 46". I gave up trying and took spreadsheet numbers to setup the weights.
As pictured; the coffee can weighs 16lb and is the lift weight.
Everything else, [riser plate & tubes] + [hardware] + [brick] is also 16Lbs.

I spent most of the time I had just trying to develop a good - repeatable(ish) setup so no numbers from this current rig yet.

Sorry to hear about the "possible" leak M. - You'll figure it out.
Dale

Love the weights under the bench idea. Its one of those ideas that is so simple- but only after someone[you] has thought of it.