Brunton TruArc 3 Base Plate Compass User Manual

Introduction

The Brunton TruArc 3 is an entry-level base plate compass designed for basic orienteering and mapping. It features the innovative TruArc Global Needle system, ensuring accuracy in both northern and southern hemispheres. Its compact and durable design makes it an essential tool for travelers, hikers, and campers seeking reliable navigation anywhere in the world.

Key Features

• TruArc Global Needle: Provides accurate readings in both Northern and Southern Hemispheres, resisting magnetic interference.
• Tool-Free Declination Adjustment: Allows for easy and quick adjustment between true North and magnetic North without the need for additional tools.
• Metric and Standard Scales: Integrated scales on the base plate for convenient map work.
• Liquid-Free Dial: Ensures reliable performance in varying temperatures, preventing freezing.
• Durable Construction: Built to withstand outdoor conditions.
• Compact and Lightweight: Easy to carry in any outdoor pack.

Setup

Your Brunton TruArc 3 compass comes ready for immediate use. Before heading out, familiarize yourself with its components and ensure the compass needle moves freely.

Attaching the Lanyard

The compass includes a lanyard for secure carrying. Thread the lanyard through the designated hole on the base plate. This helps prevent loss and allows for convenient use around your neck or wrist.

Figure 1: Brunton TruArc 3 compass with attached lanyard.

Operating Instructions

Understanding Your Compass

Familiarize yourself with the main parts of your TruArc 3 compass:

• Base Plate: The clear plastic plate with rulers and an arrow (direction of travel arrow).
• Compass Housing: The rotating capsule containing the needle and degree dial.
• Global Needle: The red (North) and white (South) magnetic needle.
• Orienting Arrow (Shed): The non-magnetic arrow inside the compass housing, used to align with the magnetic North needle.
• Orienting Lines: Parallel lines inside the compass housing, used to align with map grid lines.
• Degree Dial: The rotating ring with 360-degree markings.
• Scales: Inch and centimeter rulers along the edges of the base plate.

Figure 2: Components of the Brunton TruArc 3 Compass.

Tool-Free Declination Adjustment

Magnetic declination is the angle between magnetic North (where your compass points) and true North (geographic North). This angle varies depending on your location. The TruArc 3 allows for easy adjustment:

1. Hold the compass firmly.
2. Grip the compass housing (the rotating part) with your thumb and forefinger.
3. Rotate the housing until the desired declination angle (found on your map) aligns with the index mark on the base plate. The compass housing is designed to rotate smoothly for this adjustment without requiring any tools.

Figure 3: Hands adjusting the declination on the compass.

Orienting a Map

To align your map with your surroundings:

1. Place the compass on your map with the direction of travel arrow pointing towards the top (North) of the map.
2. Rotate the compass housing until the orienting lines inside the housing are parallel with the North-South grid lines on your map.
3. Keeping the compass and map together, rotate both until the red (North) end of the magnetic needle aligns with the orienting arrow (shed) inside the compass housing. Your map is now oriented to true North (if declination was set) or magnetic North (if declination is zero).

Figure 4: Compass placed on a map for orientation.

Figure 5: Using the compass and map in the field.

Taking a Bearing

To find the direction to an object in the field:

1. Point the direction of travel arrow on the base plate directly at the object you wish to take a bearing to.
2. Rotate the compass housing until the red (North) end of the magnetic needle aligns with the orienting arrow (shed) inside the housing.
3. Read the bearing where the direction of travel arrow intersects the degree dial. This is your magnetic bearing to the object.

Using Scales

The base plate includes both inch and centimeter scales. These can be used to measure distances on your map, provided you know the map's scale (e.g., 1:24,000).

Figure 6: Compass dimensions and scales.

Maintenance

• Cleaning: Wipe the compass clean with a soft, damp cloth. Avoid abrasive cleaners or solvents that could damage the plastic.
• Storage: Store your compass in a cool, dry place away from strong magnetic fields (e.g., magnets, electronic devices, car speakers) to prevent demagnetization of the needle.
• Liquid-Free Design: The TruArc 3 features a liquid-free dial, eliminating issues like bubbles or freezing that can affect liquid-filled compasses.

Troubleshooting

While the Brunton TruArc 3 is designed for reliability, here are some common issues and their solutions:

• Needle Not Pointing North Accurately:
  • Ensure you are away from any magnetic interference (e.g., metal objects, power lines, electronic devices).
  • Verify that the declination is correctly set for your current location.
• Needle Sticking or Sluggish:
  • Check for any debris or foreign objects on the compass surface or inside the housing.
  • Ensure the compass is held level and steady during use.

Specifications

Warranty & Support

The Brunton TruArc 3 Base Plate Compass is backed by a Manufacturer Warranty, including the "U-Proof Warranty" as highlighted in its features. For specific details regarding warranty coverage, claims, or technical support, please refer to the official Brunton website or contact their customer service directly.

For further assistance or inquiries, visit the official Brunton website: www.brunton.com