Reviewed by: CAPT. MIKE SCHOONVELD            

Much of the time, fishing without a “probe” to measure the temperature of the water at the depth the lure is being trolled and/or the speed of the lure is like star gazing at night while wearing sunglasses. Salmon, trout, walleyes and other fish often relate to water temperature and down deep, where the cool water is located, lake currents make relying on GPS or other speed readings imprecise. 

In short, knowing the speed and water temperature down where your lures are positioned is far more important than the speed and temperature at the lake’s surface. You’ll see more stars when you take off your sunglasses. You’ll catch more fish when you use a “probe” device. 

“Probes” are all two-part products. Part one for most of them is a about the size of a D Cell flashlight that connects to a downrigger cable just above the weight probe to measure the speed and temp. Part two is a unit on the boat to display the readings being measured in the depths. I’ve used all of the popular brands; I currently have a Fish Hawk X4 on my boat. So why was I willing – even excited – to put the Smart Troll II on my boat?

Because the size and drag caused by the X4’s (and others I’ve used) big probes creates a significantly greater amount of blowback on the ‘rigger with the probe on it. This makes setting a lure at a specific depth somewhat imprecise and occasionally causes tangles with adjacent downrigged lines. The Smart Troll II probe is about 80 percent smaller than the probe on my X4; and in addition, the display registers the true depth of the probe in along with the speed and temp.

Since the ST probe is small, it just clips to the downrigger wire with an Offshore OR-16 pinch pad. If the downrigger ball is lost, the probe will still be on the cable.

Or just don’t run the Smart Troll probe on your downrigger at all. The speed measuring part of the probe can be removed and without it, the temperature and depth measuring part of the probe is the size of an AA battery.

“Many guys don’t worry about the speed so much, and put the temperature and depth probe just ahead of or behind their Dipsey Divers,” said Darrell Huff, owner of Smart Troll. “They let out line on their diver gradually, not as much worrying about the amount of line as watching the temperature readout as the diver goes deeper. Once the temperature shows the diver is in or under the temperature break, the Smart Troll will show it’s exact depth. From there, the fisherman can set his downriggers and by checking the line counter on the diver reel, use that reading to position other divers.”

Or, put one of the probes on each diver. Or put temp probe(s) on the divers and one with the speed attachment on a downrigger to monitor the boat’s trolling speed.  Probes are sold separately or in kits with two to six probes.

There’s no display unit to mount somewhere on the boat. Instead, the probes “report” to a receiver (a black box which can mount anywhere on the boat) and the receiver sends a Bluetooth signal to your Android SmartPhone. Here’s the kicker – the SmartPhone App will monitor up to six probes simultaneously – showing the true depth at the probe and the speed at the probe if the speed attachment is mounted.  Available from

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s