One of mine broke a few years back. I managed to rough up the insides of the plastic shell with coarse sandpaper. Was able to fit or tape the broken pieces back together, then set them level and poured the support full of epoxy. Was probably 10 years ago and it's held perfect since.
On a related note, one of the unexpected benefits of building a boat was having huge amounts of epoxy available for such tasks. Talking a half gallon or more, not the little half ounce tubes you see in the hardware store.
You can also order much larger tubes of JB Weld for such tasks.
