I've got a good story.
I bought my first (and only, so far) cat from my boss for $100. A tetherball was attached to the very top of the mast. Being a newbie, I hesitatingly asked him what in the world it was for! He said it was to prevent the boat from turtling. I nodded understandingly, but inside I was saying, "No way am I going to get on the water with a tetherball tied to my mast!" It was the very first thing I removed when I got my new baby home.
My first few trips out went well. I got braver and decided to try the mighty Columbia River. The day was windy, probably 20 knots or more, with a few whitecaps, and NO OTHER BOATS on the water. I barely made it out of the marina and quickly decided I was not up to this kind of wind. I fell off the wind and headed to shore. But I could tell that I was not going to be able to point back to where I had started...it was looking like I'd land on the beach 2-3 miles downwind. I tried to point higher, my starboard hull climbed high over a wave, and the wind knocked me completely over. With no float on my mast, I turtled and was there for the duration. In the middle of the channel, only about 1 hour of daylight left, and barge traffic every hour or so.
After the sheriff's boat righted me, snapping a shroud and bending three cross bars, I was towed to the marina. The next morning I surveyed the damage and immediately vowed to re-install my tetherball.
Now I proudly fly my tetherball, knowing that it will help the next time I overestimate my ability and underestimate the wind.
My mast has foam inside, but it must not be sufficient to keep it afloat. I heartily recommend a mast float!
Milt Reynolds