Sonar Frequencies Explained: 83kHz vs 200kHz

Modern bait boats aren’t just about delivering rigs – they’re powerful fish-finding tools. With built-in sonar systems, you can read depth, water temperature, bottom structure, and fish activity in real time. But one question often comes up: “Which sonar frequency should I use – 83kHz or 200kHz?”

In our latest guide, we’ll break down what these frequencies mean, how they affect detection range and accuracy, and how the Sailvvay C-Series and M-Series bait boats use this technology to give anglers a real edge.

Understanding Sonar Frequencies

Sonar works by sending sound waves into the water and measuring how long it takes for them to bounce back. Different frequencies provide different results:

  • 83kHz – A lower frequency, producing a wider cone angle and covering a larger area beneath the boat. Ideal for scanning broad zones and spotting fish activity over a wide range.
  • 200kHz – A higher frequency, producing a much narrower cone angle but with greater detail and accuracy. Perfect for pinpointing specific features or fish directly under the boat.

How the C-Series Uses 83kHz vs 200kHz

The Sailvvay C-Series features dual-beam sonar with selectable 83kHz and 200kHz modes, allowing you to adapt based on the water you’re fishing:

  • 83kHz – 60° wide beam, ideal for shallow waters and scanning large areas for signs of fish or features.
  • 200kHz – 20° narrow beam, capable of detailed readings up to 80m depth with 0.1m accuracy.

This dual-frequency flexibility means you can start with 83kHz to locate general fish-holding areas, then switch to 200kHz for fine-tuning your rig placement.

M-Series Sonar Settings

The Sailvvay M-Series uses a single 45° sonar cone with a detection range of 0.8m to 40m. While it doesn’t offer dual-frequency selection, it is optimised for reliable all-round use with features like:

  • Fish size detection (small, medium, large)
  • Water temperature and structure mapping
  • Adjustable sensitivity and noise filtering
  • Shallow/deep water alarms for easy navigation

For anglers who primarily fish small to mid-sized UK lakes, the M-Series provides more than enough range and detail.

When to Use 83kHz vs 200kHz

Choose 83kHz when:

  • You’re fishing in shallow water (up to 10-15m)
  • You want a wide scan to identify fish activity or bottom contours
  • You’re mapping an area quickly

Choose 200kHz when:

  • You need precise depth readings on small features like gravel patches
  • You’re targeting deeper water (up to 80m on the C-Series)
  • You want more detail about fish size and structure directly beneath the boat

Tips for Getting the Best Sonar Readings

  • Start with 83kHz for wide-area scanning, then narrow in with 200kHz for exact placement.
  • Adjust sensitivity based on clarity – high sensitivity for deep, open water; lower sensitivity for weedy or cluttered zones.
  • Watch water temperature – cold pockets or warmer layers can indicate where winter carp may hold.
  • Mark spots using the GPS memory – both the C-Series and M-Series can store your best sonar-identified locations for repeat drops.

Why Sonar is a Game-Changer for Bait Boats

Sonar-equipped bait boats take the guesswork out of feature finding. Instead of relying on marker floats, spods, or cast leads, you can map the lakebed in minutes and know exactly what’s beneath you.

The combination of GPS positioning and dual-beam sonar (C-Series) means you can not only find features but also drop rigs with perfect accuracy – time after time.


Which Frequency is Best?

There’s no single “best” sonar frequency – it depends on your water and your target fish. For anglers who want versatility, the C-Series dual 83kHz/200kHz system is unbeatable. For those fishing smaller, shallower venues, the M-Series’ all-round 45° sonar cone offers superb simplicity and clarity.

Ready to take your fishing to the next level? Explore the full range of Sailvvay bait boats at Sailvvay UK.