I was just curious if sand is really bad on a surface drive mm?

Seriously?
If you run sand, you're gonna burn thru some props. If you hit a sand bar, it's probably gonna land you on your azz in the front of the boat when it comes to the abrupt stop. Other than that, I can't think if anything else it'll hurt just by passing thru it.

Sent from my Droid because I'm trying to be as cool as you someday.

Mix about 1/4 cup of sand with your engine oil and your mm will be able to run through sand like a chainsaw through butter.

I run lots of sand and gravel with a Prodrive rock guard. You can't run as shallow but it will go just fine as long as you got at least 8" of water. Get a rock guard so you don't push your prop into the sand it will go good.