[Dion1716]

I have experienced the fixings perspex cracking on both the stand off piece that is sandwiched between the hinge and the transom and also on the piece acting as the flap.  I ended up using some perspex that was a little thicker and more robust.  But thinking some more of your problem is the tensioning sufficient to hold the flap against the transom or has the elastic gone to stop it sealing up. Just a thought.  Dion 1716