Will a metal block float in water in such a scenario?

Question

So I was having a doubt of why metal block sinks in water. I was wondering why water molecules that have the capacity to exert pressures supporting the water columns at depth of say Mariana Trench cannot lift a block of iron.

With a bit of help, I came up with this explanation:

1. The block is placed in water$\implies$ Pressure on the surface molecules increases.
2. Lateral pressure is equal to upward pressure. (As aso explained in this question and this question)
3. Moecules experiencing the extra pressure shift in other directions to regions of lower pressure(1st layer of molecules is shown by darker blue line) and the block sinks a little.
4. The shifted water, that above the second layer(& above the block) and the weight of the block increase pressure on $2^{nd}$ layer of molecules and the process(sinking) continues.
5. The reverse happens for floating.

These questions (1 and 2) seem to agree that pressure difference is the cause of upthrust.

• Is my explanation correct?

I am hoping it is correct, which brings us to the real question.
The same block is put in the centre of a U-tube (some kind of teleportation or maybe it is suspended by string that later dissolves) in this way

• Given sufficient height of arms of the U-tube(columns), will even metal float?(irrespective of density differences?)

Answer 1

This doesn't have to do with pressure, it has to do with density. Ocean water varies in density from about 1.03 g/cc at the surface to 1.08 g/cc at the ocean floor. Iron, meanwhile, is 7.9 g/cc. Hence it will never float on water.

However, it might interest you to know that iron will float on mercury, which has a density of about 13 g/cc. You can see images and videos of this.