For many years I was a member of the Narragansett Saltwater Fishing Club. Our club house is right at Deep Hole so it was a go to spot for all the guys all season. I probably fished the hole 1000 time.
You want to get out of the rock/rubble bar as far as you can to hit the Hole. This requires fishing it at low tide. If you fish on the beach at high tide you will be casting into 2 feet of water. On a moon low you can get out over 150 yards from shore. Use poppers or needlefish as swimmers will just roll in the surf. Cast across the waves toward the Point Jude Light way in the distance. The fish will hit between the waves. Oh yeah, wear Korkers as wading the bar is like walking on slimy bowling balls.
There! You now have all the secrets, (almost) to fishing The Hole.
