Partial collapse in deep end of vinyl pool

[LotusRacerX]

Just noticed this today. My vinyl pool has suffered a partial collapse in the ramp area of the deep end.
About 2 feet long, 1 edge is a bit sharp, but liner has not torn yet. Pool is 16 years old, liner about 4 years old.
Bottom is built upon Georgia red clay, with a thin layer of, I think, vermiculite.
Haven't had someone out to do an estimate yet. Thoughts on whether the liner can be pulled back, the hole repaired in the floor, and liner re-applied, or am I looking at a new liner as well?

 

[ajw22]

@jimmythegreek thoughts?

 

[LotusRacerX]

Is there a version of this where I leave it alone, and the liner lives out a quiet life of 8 more years?

Or do I need to address it before it tears and causes an erosion disaster?

 

[jimmythegreek]

Hard to tell from pics. If its busted a chunk of vermiculite and its sharp edged it could tear liner. If its somewhat smooth you could wait and see what happens. These are a real pain to fix when they are in deep end it's difficult to get liner back in when thwres a light or penetration nearby

 

[LotusRacerX]

Just went in to feel it out. Not as deep as I thought, maybe 4". Break is straight across back wall, and bowl shaped, with a sharp-ish break on both ends. It is 3-4 feet long, and actually crosses the diaginal seam.
I took more pictures, but the night shots with the light show it better.

 

[jimmythegreek]

I can see it in that pic. It's right up against the bottom of the wall by looks of it. Not a good spot if any. Hopefully you dont have undermining of the concrete collar. Might be able to drape that back and see what's up if theres room and no liner penetrations nearby

 

[LotusRacerX]

More, better photos today on a cloudy day. Yes, when I felt the depression, it goes down straight with the wall for a couple inches, then curves in.
None of it feels "soft" or "Squishy". I was able to stand in the depression, and it felt solid.

PS: Can you explain what a "concrete collar" is? I think I have photos of the pool bottom from 4 years ago liner change, if that would help.

 

[LotusRacerX]

October 2016...collapse will be to the right of the pool light, ending in the gray spot that looks like a patch on the vermiculite.
I don't remember them doing any patching, or even powerwashing to clean the algae/mold.

EDIT: Found a second photo right after removal of the old liner. Looks like the gray patch was something my pool builder put down after removal.

 

[LotusRacerX]

@jimmythegreek any update, based on my new pics? Had the pool builder out today, he thinks he can patch it for around $650, preserving the liner.
1. Drain water. 2. Peel back liner under water feature, up to but not including the light. (So as not to disturb screws.)
He says we'll have to see what he finds under there to see if there is anything more extensive going on. (Like if our palm roots are causing this.)
Cost might go up from there.

 

[jimmythegreek]

Looks like a cement patch they threw in. Behind that wall panel should be a concrete collar around the pool wall bottom. That's below the collar so something is decaying there for it to sink in. Very fair price for a patch up, its probably gonna be temporary amd happen again if its organic material buried in there

 

[LotusRacerX]

Got an official estimate today of $825. Still fair, if it holds.
They are busy building pools, due to COVID, everyone wants that oasis, so they can't start until Jan 2021.