He’s probably tried a few visual ball finders, but they don’t work underwater. Before he rents some scuba gear, you should tell him to checkout the Golf Ball Wrangler.
The Wrangler is decidedly low-tech, but it gets the job done. It’s basically a series of plates mounted on a spindle. You toss the Wrangler in the water, pull it across the bottom of a pond, and the balls get trapped between the plates. It’s simple and brilliant. [Gizmag]