I learned this actually because I was at a Scottish Highland festival this weekend where they were shooting cannons into a lake and they used bowling balls so they could get them back.
I found this out when I was about 10 years old, one of my grandfather's friends took us fishing and he was a big practical joker. This time, he used a bowling ball as an anchor and when we stopped to drop our lines this guy made a huge show of pulling this ball out that he had attached a rope to. He was so proud as we watched him ham it up trying to pick it up and throw it in the water, only to have it splash in the water and immediately start bobbing like an apple. I don't even remember if we caught any fish that day, but I had never laughed so hard when the utter look of confusion passed over his face as he realized that bowling balls make terrible boat anchors.
Now I'm left wondering how many bowling balls are out there floating in the ocean
Maybe someone smarter than me can answer this, but doesn't the pressure of water change with depth? Wouldn't you reach a state of neutral buoyancy for some of the lighter balls?
Edit: The answer to my question is no, because the increased pressure is exhibited on all sides of the bowling ball, not just the bottom. Thanks u/google
So witches are made of 12lb bowling balls?
Anyone else a little annoyed that he mentions that the ball might reach California by 2018 but the post has no publication date so we can't tell how long that is? It could have been written in 2012 or 2016...
I love What-if XKCD. It's the best of Randall's work, honestly. Fun fact, if you click on the reference numbers (the little  and  in this story) they usually have hidden jokes in them too, just like the mouse over text on the images.
Also, TIL. Thanks OP :D