Mastering Your Sonar: Maximizing the Potential of Your Depth Sounder
Navigating the open waters safely requires a well-configured depth gauge and plotter. Here's how to set up your instruments for clear underwater navigation and hazard warning.
Depth Alarms
Setting a minimum depth alarm that matches your vessel’s safe draft plus a safety margin is crucial. This alarm will alert you if the water depth falls below a critical level to avoid grounding. For instance, if your boat needs 6 feet minimum, you might set the alarm at 7 or 8 feet to account for waves and measurement errors.
Colors for Depth Visualization
Color coding on sonar and plotter screens uses green for safe depth, yellow for caution zones, and red for danger or shallow water. This immediate color feedback helps you quickly identify underwater hazards ahead and make navigation decisions accordingly.
Contours
Use contour lines on the plotter or chart to indicate changes in depth. These parallel lines show how deep the water is at different distances, letting you anticipate shallow areas or underwater features. Many modern chartplotters display enhanced colored contour shading—deeper water might be indicated with blue shades, shallower areas with lighter colors or red at very shallow points.
Forward Range and Warning Zones
When configuring your device, input critical settings like your boat’s forward sonar scan range and the depth warning parameters. This tailors the depth information to your boat’s speed and sonar mounting position to maximize safety and accuracy.
Adjust Display Settings
Choose how much previous sonar history to display to track trends or anomalies on the bottom. Some systems allow a bird’s eye chart view with a vessel icon, which helps visualize your position relative to underwater hazards.
Installation and Visibility
Ensure the depth gauge display is easily visible in all lighting conditions—day and night—and that the installation is secure and correctly wired. Separate alarms such as horn alarms may need additional mounting.
Before venturing into shallow areas, it is important to study the chart to see what the sea bed is composed of. Physical charts are often easier to use for this purpose, but digital charts are beginning to provide similar information.
Approaching a darker shade of blue on the depth display should increase focus on the depth display. It is recommended to double-check the depth setup before setting off using a weighted line with knots at 1m intervals.
The Navionics plotter can be set to read progressively darker blue as it shallows from the 5m contour. The depth alarm can be set to any depth, but it is common to set it to 2m below the keel for an early warning.
The depth alarm can prevent accidents, like nearly cutting across a shallow patch due to a hidden navigation marker. It can also be used as a navigation aid to help locate the next port channel marker or other navigation markers.
In certain situations, such as when going into a shallow area to anchor or explore further up an estuary, it may be necessary to relax the set limit. A safe limit for how shallow a boat should go is typically 2m below the boat's lowest point, often the propellers on a planing craft. It is possible to set the depth alarm to 2m below the keel for navigation assistance when approaching the right depth for anchoring.
In conclusion, safe boating with depth instruments involves setting conservative depth alarms, using the standard color codes (green/yellow/red) for easy hazard identification, configuring contours and ranges based on your boat and route, and adjusting display preferences to maintain situational awareness. Regular calibration and testing in shallow and deep water can confirm accurate readings.
Jon Mendez discusses the importance of knowing the depth of water below a boat for safe boating.
- To ensure a smart yacht navigating shallow waters, consider setting up a depth alarm that matches the vessel's safe draft plus a safety margin, alerting you when the water depth falls below a critical level, avoiding grounding.
- For a clear visualization of the underwater landscape, use a plotter or chart with color-coded contour lines, showing changes in depth and enabling you to anticipate shallow areas or underwater features.
- Maximize technology on your flybridge yacht by installing and configuring smart-home devices and gadgets, such as depth alarms, that offer the newest advancements in marine technology, enhancing situational awareness and increasing overall safety.
