How to Pair, Calibrate, and Optimize Your Simrad System

Modern boating is all about precision, safety, and ease—and that’s where Simrad autopilot systems excel. Whether you’re running a Simrad AP44 Autopilot Controller, NAC-2/NAC-3 Autopilot Computer, NSX Chartplotter/Fishfinders or a NSS Chartplotter, seamless integration ensures smoother steering, better efficiency, and hands-free confidence on open water.

1. Pairing Simrad Autopilot with Your Chartplotter

Simrad autopilots connect effortlessly via NMEA 2000 or SimNet networks.

To integrate:

• Ensure all devices (chartplotter, NAC computer, rudder sensor, and controller) are on the same NMEA 2000 backbone.
• Power up your system and access Settings → Autopilot → Commissioning on your Simrad GO, NSS evo3, or NSX display.
• Select “Find Autopilot Computer” to pair automatically.

This quick pairing allows your chartplotter to display and control heading, route tracking, and navigation data directly.

Check NMEA 2000 wiring, ensure Simrad autopilot is recognized in the chartplotter's device list, and ensure the NMEA 2000 Output Bridging setting is enabled.

2. Setting Up Steering Modes

Simrad offers flexible steering options for every type of vessel:

• Auto Mode: Maintains a set heading automatically.
• NoDrift Mode: Combines GPS course tracking to hold a fixed path over ground.
• Nav Mode: Follows routes created on your chartplotter.
• Wind Mode (for sailboats): Keeps a constant wind angle for efficient sailing.

These modes can be easily adjusted through an AP44 Controller or touchscreen chartplotter interface.

3. Tuning PID Parameters for Precision

To fine-tune steering responsiveness:

• Access Autopilot Settings → Rudder Gain / Counter Rudder / Autotrim.
• Adjust Rudder Gain for quicker turns or smoother corrections.
• Use Counter Rudder to control overshoot when changing heading.
• Set Auto Trim to help your system learn your vessel’s steering behavior over time.

Fine PID tuning can greatly improve handling, especially for larger or heavy-displacement boats.

1. Perform the auto-tuning sea trial

• Run the procedure. Engage the auto-tuning function, which will cause the boat to perform a series of S-turns. The process usually takes a few minutes.
• Operate at normal speeds. Run the test at the speeds you typically use. For high-speed vessels, it is important to check the pilot's behavior at speed, but you should work up from a slow speed to be safe.

2. Manually fine-tune the parameters

Rudder Gain (Proportional)

• Symptoms of poor tuning:
  • Gain too high: The boat will oversteer and weave or oscillate from side to side.
  • Gain too low: The boat will be slow to respond to course changes and may not hold its heading well, especially in turns.
• How to adjust:
  • For high speeds, you generally need less gain.
  • For slow speeds and turns, you need more gain.
  • Gradually increase the gain until you see stable, diminishing oscillations, then back it off slightly.

Auto Trim (Integral)

• Symptoms of poor tuning:
  • Learning too fast (high integral action): The autopilot can develop an offset and "chase" small heading changes, leading to an unstable course.
  • Learning too slow (low integral action): The boat will constantly drift off a straight track in a consistent wind or current.
• How to adjust:
  • With the autopilot off, steer a straight course. Engage the autopilot and watch if it holds the heading.
  • Change engine speed and see if the heading changes. The autopilot should compensate.
  • If compensation is too slow, reduce the "auto trim" setting to allow faster learning.

Counter Rudder (Derivative)

• Function: Applies rudder in the opposite direction to halt the momentum of a turn and prevent overshooting the target heading.

• Symptoms of poor tuning:
  • Counter rudder too high: The boat may appear sluggish when entering and exiting turns.
  • Counter rudder too low: The boat will overshoot its new heading significantly.
• How to adjust:
  • Make several large, deliberate course changes (e.g., 20–30 degrees) to port and starboard.
  • Observe how the boat settles on the new heading.
  • If it consistently overshoots, increase the Counter Rudder setting.
  • If it undershoots, decrease the setting. This parameter also helps the pilot manage waves, so fine-tuning it is important for a smooth ride.

Response Level

• Function: A broad setting that can change the aggressiveness of the entire autopilot, from slow and smooth to fast and aggressive. The "response" setting from 1 (fast) to 5 (slow) is a common parameter on Simrad units.

• How to adjust:
  • Start with a normal speed setting.
  • If the steering feels too aggressive or overcorrects in calm water, decrease the response level.
  • If the boat is sluggish to respond in rough conditions, increase the response level.

Critical pre-tuning checks

• Rudder feedback unit: If your vessel has a physical rudder feedback unit, check for slack and make sure it is mounted correctly. For boats with Virtual Rudder Feedback (VRF), this step is not necessary.
• Compass: Calibrate the compass and check for interference from nearby metal objects or electrical equipment.

3. Optimizing Performance & Reliability

Maximize your Simrad autopilot’s performance with these tips:

• Keep your compass and rate sensor clear of metal or magnetic interference.
• Update firmware regularly on your NAC computer and chartplotter.
• Combine your autopilot with a Simrad Precision 9 Compass for better heading data.
• Use Simrad HALO Radar and AIS integration for advanced collision avoidance while under autopilot control.

Simrad Autopilot Products Available at Suncoast Marine & Auto

Shop a few of our Best Selling Simrad systems and accessories:

Each component is designed to integrate seamlessly, providing a complete, reliable helm control experience.

Final Thoughts

Integrating and optimizing your Simrad autopilot system doesn’t just make boating easier—it makes it safer and more efficient. Whether you’re navigating coastal routes or long offshore passages, Simrad’s intelligent control systems ensure your vessel performs exactly how you want, every time.

Suncoast Marine and Auto is an Authorized and Trusted SIMRAD Dealer