When you've seen enough broken stuff sometimes it gets mixed up as to what was broken on what boat. IIRC our club's Catalina 27 spreader casting failed. I believe the mast was down for some other repair and when the spreader was pulled off you could see the casting was cracked. We also replaced the eyes that the lowers connect to with the u-bolts from Catalina Direct.
We also had an aluminum
spreader casting fail on a Neptune 24, but that one had help. Someone had replaced the bridle
on the spinnaker
pole with an eyestrap in the middle of the pole as a fix for the broken bridle
. Predictably the first time there was any wind
pole folded up and the shock to the mast broke the spreader base, I believe it was the part sticking out the bottom to attach the lowers to snapped off.
Don't know how common it is for these bases to fail, but I'm not impressed with lightweight aluminum castings.