hello from sydney
Glad you had fun.
You actually sat on the boom DOWN WIND, simply put, your butt was a preventer. It kept the boom from jibing, I am guessing they had a spinnaker up at the time or had poled out the headsail to the opposite side of the mast as the main sail.
The boom was unlikely to snap as the sail was supporting the whole thing like a hammock.
Enjoy the top 5 placing, they make the lesson in humility of coming stone motherless last all the more poignant. That one will happen too, sometimes.