Weel, to me, if you will be water hunting, the detector should be waterproof. That narrows it down. Do you want to dig everything or discriminate. How much of that water is salt water ?
If you will be hunting is salt water and want to dig everything, then a pulse detector is the way to go. Just remember you will be digging little bits of wire, iron, etc. at nice depths. (Eric Foster Aquasearch or water proof Goldscan, Garrett Infinium, Detector Pro Pulse, Tesoro Sand Shark, Whites Surf PI Pro).
If you don't want to be digging every target, and want to discriminate out iron, than a water prroof VLF is the way to go ( Minelab Excal, Whites Beach Hunter ID, Tesoro Tigershark)
There are LOTS to choose from.
