Why the autorelease pool is necessary in main.m?

Pool caved in? Could this be the reason why?

• I have an above ground pool that a part of the pool caved in. Only 2-3 poles caved in, the hole thing didn't cave in. My pool cover was on extremely tight this winter and all the water, ice, and snow sat on top of the cover without using the pump to take the water off the top. My boyfriend talked to his uncle who worked/works at a pool place he told him that the cover couldn't have caused the pool to cave in.. That the reason had to be there was a hole in the lining.. Is it possible that it was the cover and the water sitting on top all winter? Also what are the chances that we can fix this without buying a new pool? Thanks!

• Answer:

  Your cover was on too tight or your liner had a hole. It could have been either or both at the same time. Ideally you want a cover large enough that it runs down the wall vertically to the water's surface and then does a 90 degree turn onto the surface. If the cover doesn't do this then the weight of the water on top of that "trampoline" will cause something to let go. A proper fitting cover relies on the pool water underneath it to support the water on top of it. There's absolutely no stress on the cover anywhere. It's like there's nothing on top. It could fill on top from snow/ice and rain to the brim and still have no stress. A cover that has a slope instead of that 90 degree turn where it meets the pool water surface has stress. Have a look at your current water level in the pool. If it's well below the level you drained it to at closing ( just below the pool return) then a leak in the liner caused the pool level to drop giving no support to the cover water and debris. If the level is fine then the culprit is a too tight cover in the first place. Edit: I'd also have a close inspection of the top rails and where they connect. It's quite possible that also had a bearing in this since the top rails of most kits aren't designed to take on a couple tons of water from that angle but my bet is on what I'd posted earlier that caused the event.