@Mike.Ends
...additional info added to Message 10.
Continuation...
Step 5
...after entering SIMPLIFY
sketch a rectangle on the YZ plane as shown.
Be sure one corner is anchored to the Origin. The size of the rectangle does not matter as long as it is larger than the tank.

Extrude - Intersect the rectangle by a convenient distance.

Finish SIMPLIFY.
Step 6.
Place the Load on the inside face.

Step 7
Place a Frictionless constraint on one of the cut faces.
(Repeat this for 4 separate Frictionless constraints.)
Oops, I made 2 mistakes - this is the first mistake. The geometry needs to be free to deform in one direction along (x axis in this case). So should be 3 Frictionless constraints.
Step 8.
From the Manage tab go to Settings
and checkmark Remove Rigid Body Modes.
Oops, I made two mistakes - this is second mistake. Leave this unchecked.
Step 9.
Mesh the geometry. Observe the mesh.
From the Mesh Control adjust such that there are at least two elements (some recommend 3) across the thinnest section of material.


