Both mine have discoloured and then broke on our (2009) Cruiser 31. Same happened with a similar vintage B34 out here. I couldn’t figure out how these universally break in a “shattered” manner until I realized it was from jib sheet flogging and that ours had happened during some reefing drama. Anyway, I upgraded to stainless steel covers bought from Beckson Marine (C6-rs). They’re great and you can put them on without doing any modification to the vent structure that goes into the cabin. Here is a pic:


    Riyad Abu-Laban
    s/v Battuta
    B31: Vancouver Canada