Before I go into this, just know I have absolutely no experience making or designing yoyos.
So I had this idea, what about a yoyo that would work underwater? ??? I was thinking a yoyo made out of lead or something with a giant weight rings, and very grooved surface that would trap miniature air bubbles and bring them under the surface, so that when the yoyo spins, in covered in a haze of bubbles, so the water doesn’t slow it down. Of course, its bearing would need to be a special non-rusting alloy. So any thoughts on my idea?
Tht would be awesome! But I dont think thats possible at the moment, and if it was, i think it would cost way more than its worth…
Probably. like I said, this was just a random idea, but if someone made one, I’d be the first to by one.
The string would be affected by water as well as your ability to see, breath, and do whip, slack, pop, and mounts.
The haze of bubbles would float to the surface.
I was about to say, I’m very sad as a physicist to inform you that your idea may be impossible 
but I’m sure if you came up with a thought like that, you could come up with one that works sooner or later 
My first concern would be just how the yoyo is thrown originally. You can’t exactly move your arm very fast underwater, especially not if you’re holding something and making a fist. Even if the yoyo could work, which I rather doubt, a throw that was too weak to actually move it down the string any significant amount would be the end of it.
Also, water is actually a really poor lubricant. I’d wonder about its effect on a ball bearing given how much “better” oil lubricants slow it down already.
What if you used static to repel water?
Now that is a great idea.
Yeah, except the sheer amount of electricity would explodetonate the water molecules.