While I live in the desert, we have a second home in Florida that is about five miles from the Atlantic Ocean. Also, I used to live about 8 miles from the famous Santa Cruz Beach... one of the toughest beaches to hunt in the world because of the "black sand". I say this only because I have a ton of experience beach hunting.
Without question, a water-proof Pulse Induction (PI) machine is the best "model" you will ever have for beach hunting. PI's don't discriminate and have incredible depth. A good PI detector will send you digging to China to recover the back of a gold stud ear ring.:lol:
Wet sand, dry sand, in or out (or even under) the water... no big deal to a PI machine.
I have an old White's Surfmaster Pro (single frequency) that has been modified a bit over the years. It's been loaned to folks from the mid-west to take on vacation literally all over the world.
Now days, the newer generation of Surfmasters have a Dual-Field feature that provides two frequencies, and are very nice and easy to use. If you're gonna "put your big-boy pants on" and seriously want to beach hunt, don't fool around with any VLF machine that discriminates. I highly recommend this one:
http://www.whiteselectronics.com/surf-pi-dual-field
Expensive? Yes, but I've found literally thousands of dollars worth of jewelry with this machine.
BTW: Hairpins will drive you nuts on a beach. After a little experience with a PI, you'll be able to "hear" hairpins. Trust me. :lol:
(Note: I have no particular allegiance to White's machines, and while I seem a tad narrow-minded, I simply know what works.

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