Hayward Skimmer Flaper Broke

[Poconos]

That flapper is a weir and just keeps debris caught by the skimmer from going back in the pool when the pump turns off. May also create a little better skimming action. Have you tried PVC cement? Yellow can, multi-purpose. Depending on where it broke it may not be fixable. I don't know specifically but it would seem like an easily breakable piece and should be able to be replaced easily, if you can find one.
Al

[Watermom]

I don't have a weir on my skimmer. Mine broke years ago and never was able to find a replacement for it that would fit it. I just try and remember to empty the skimmer basket before turning off the pump so the stuff doesn't just float back out into the pool.