We at Boats.com love search engines like Google and the information-rich places they can take you— but we also realize that there’s a lot of misinformation out there. Marine electronics like radar, fishfinders, and VHF radios aren’t immune to bogus bloggers and deceiving data. So we’re going to set the record straight on five big marine electronics myths we’ve seen propagated on the net. Don’t let ‘em fool ya.

In many situations, radar range is limited more by antenna height than power.


1. More powerful radar can “see” farther into the distance. Sure, there’s some truth to this, but on virtually all modern powerboats, your radar range is going to be limited by the curvature of the earth long before the unit’s power even becomes a consideration. Radar transmissions don’t bend, so the height of your radar antenna and the height of the target will most often determine how far off you can see something. Luckily, the mathematicians have a formula that will tell you just how far your radar can see: 1.2 nautical miles times the square root of the height of your radar, plus 1.2 n.m. times the square root of the height of the target. Let’s say your boat is a flybridge convertible with a hard top that’s 16 feet off the water, and you’re looking for a boat that’s about the same size. The formula would be 1.2 x 4 + 1.2 x 4 = 9.6. No matter how powerful your radar may be, it won’t see the other boat until you’re within 9.6 n.m. Considering that even low-power radars have a minimum range of over 20 n.m., more power simply won’t make a difference in cases like this.

2. More powerful fishfinders can “see” deeper. Again, there’s some truth to this assertion, but it's misleading. Yes, power helps, but it’s only half of the equation. In reality, your transducer’s size is just as important as the unit’s output power. The physical size and shape of the transducer’s piezoceramic elements (a polarized barium titanate or lead zarconate titanate disk or ring, coated in silver), determines what type of vibrations they create. And the larger they are, the stronger the pulse. All other factors remaining equal, when it comes to depth range, doubling the diameter of the transducer crystal has the exact same effect as quadrupling the fishfinder’s output power. So, a unit with half as much power as another can actually peek farther through the depths if it’s rigged with the right transducer. (For a more detailed explanation, check out our feature on how transducers work.)

3. You have to spend big bucks to get a good VHF radio. With other marine electronics, we’d usually agree that you get what you pay for. But in the world of VHF radios, a good quality unit can be bought for a couple hundred dollars and it will perform every bit as well as a $500 unit. Look around, and you’ll find inexpensive units that have the key features we all need: 25 watts of output power, DSC-capability, and IPX7 waterproofing. Beyond that, the “extras” you pay hundreds for are mere convenience items, like scanning abilities, dual-channel monitoring, and snazzy display screens.

4. Solder makes the best electrical connections. Sure, it does, on land—but not on a boat! The problem is vibration. On a boat, everything is subject to lots and lots of it. And solder is not flexible like the stranded wires it connects. As a result, it commonly breaks in short order. Stick with crimp-on connections instead.

5. Hard bottom appears as a thick line on a depth finder, and soft bottom appears as a thin line.  Actually, it’s the exact opposite. A rocky bottom will bounce back the sonar waves immediately, while the waves can penetrate a certain distance into a mucky bottom. As a result, the muck leaves a wider return on-screen.