Although they haven’t really caught on in the fishing world, portable depthfinder systems designed for use without a powered boat have been around for years.
These are not the depthfinders powered by a small battery that you’ll see on high-tech kayaks. These are transducers small enough to cast or chunk out into the water by hand. They relay information to a hand-held monitor. Great tool for anglers stuck on the bank or a pier, right?
Well, maybe. Even the latest in “castable” sonar devices, which transmit data via Bluetooth to a smart phone app, have their limitations. If you’re used to the sonar on a bass boat or an offshore rig, you’ll be disappointed. These devices don’t have near the functionality or reliability of even a low-end “real” depthfinder.
A “castable” device does have its uses for anglers without a boat, though. No, you’re not going to mark schools of bait or fish with pinpoint accuracy, but they can be used to determine depth changes or structure you might not otherwise know were there. And you can carry the unit with you, which is a bonus for anglers who fish small ponds or rivers out of jonboats, canoes or kayaks.
There are different brands like Deeper, FishHunter, Ibobber, ReelSonar and SonarPhone, and they all espouse their different bells and whistles. Most of them run on a rechargeable battery, and they are significantly less expensive than boat-based sonar systems. Even so, you’ll be sorely disappointed if you break off the $250 unit on the end of your line.