Sea strainers do exactly that and strain things like seaweed and debris out of the water before it reaches the sea water pump with the impeller. They look like coffee cans mounted in the bottom of the bilge with strainers in them.
That said, they are not that much good for sand. There is one manufacturer that markets a "sand strainer". It's supposedly does help in that arena. Do a search on here and you should find it.
If you do beach, the best way is to coast in, kill the motors, and trim it up as you approach the beach. Set an anchor or sand-spike in the sand to secure the boat vs. making sure you are far enough up on the sand to 'stay put'.
When it comes to getting off the sand, push the boat off by hand, and then fire the motors when the drives are in plenty of water.
You can't beach these things like a PWC or jet-boat.