Proper installation sounder It's a critical step in the quality of the image and the depth accuracy. Many anglers make the mistake of thinking that it's enough to just screw the pill to the board, but the nuances of hydrodynamics and ultrasonic waves require strict adherence to the technology of installation. Incorrect angle or too high installation will lead to constant failure of the echo signal at speed, which will make fishing uncomfortable.
In this article, we will discuss in detail the process of preparing, selecting the location and direct fastening of the transducer on the transducer board. You will learn how to avoid cavitation, correctly orient the emitter relative to the keel and ensure the longevity of the entire system in an aggressive aqueous environment. Garmin, Lowrance or Humminbird The principles of physics are the same for all brands.
Before you start drilling, you need to determine the type of boat you have and the nature of its operation. For aluminum boats and flat-trans fiberglass vessels, the approach will be different from mounting on hard-bottomed or soft-bottomed PVC inflatable boats. The main rule: the working surface of the sensor should be parallel to the surface of the water when the vessel is moving.
Selection of the type of fastening and preparation of tools
The first step is to determine how to fix the converter. There are several basic options, each with its own advantages and limitations. The standard transom bracket is suitable for most stationary installations where the boat is stored on a trailer or in a garage. Inflatable boats often use quick-removal clips or suction cups to quickly dismantle equipment.
If you're planning an active speed fishing, you should consider a cut-in sensor, although it requires drilling the hull. However, for a classic transom mount, you'll need a minimal set of tools. It's important to use only stainless fittings, as contact with salt water or just a moist environment will quickly destroy the ordinary ferrous metal.
Prepare the following tools and materials for the job:
- 🔧 A drill or screwdriver with a set of drills for metal and wood (depending on the material of the transom).
- 🔩 A set of stainless bolts, nuts and washers (usually M4 or M5).
- 🧴 Polyurethane-based marine sealant for insulation of holes.
- 📏 Roulette, marker and level for accurate marking.
Make sure the sensor cable is long enough to be laid down to the head unit without tension. The strained wire can be damaged by vibration or cause contacts to break in the connector. If the length is not enough, use special extension cords with the preservation of the shielding so that you do not lose the signal.
Determination of the optimal transom installation location
Finding the perfect point for mounting is a process that requires patience. The sensor must be in the zone of calm water flow, away from the engine's burblers and the structural elements that create vortices. If you install the converter too close to the engine, the air bubbles will shield the signal, creating "dead zones" on the screen.
Visually inspect the transom. The keel line or the imaginary extension of the bottom is your main reference point. The sensor should be lowered below the keel line, but not so much as to increase water resistance or the risk of impact on underwater objects. The optimal distance from the bottom edge of the sensor to the keel line is about 3-5 mm for low speeds and up to 10-15 mm for high-speed vessels.
⚠️ Warning: Never place the sensor directly in front of the engine cooling intake or next to the anodes. vortex flows from these elements are guaranteed to cause signal loss on the go.
When marking, take the angle into account. defector Many boats, when they go to the plane, they snooze their nose, so the transom goes deeper, in which case the sensor, which is set by the level of standing water, may be too deep or, conversely, too high, and experimentally installed on a temporary bracket will help to find the middle ground.
It's also important to make sure that the front face of the emitter is vertical, and if it's skewed horizontally, the sonar will show different depths under the left and starboard sides, and the picture will become blurry. Use a building level or a special template attached to some models. Raymarine or Simrad.
Technology of drilling and sealing of holes
Drilling a transom is a critical moment, especially if it is an aluminum boat or fiberglass. An error can lead to corrosion or stratification of the material. For aluminum, be sure to use a cobalt-coated drill and coolant so as not to overheat the metal and not spoil the drill.
The process of creating the mounting holes must be clean and neat. First, the centers are outlined with a core, then a small-diameter drill is made with a pilot hole, which is then drilled to the desired diameter, the edge of the hole must be cleared from the burrs and treated with corrosion-resistant compound.
Sealing is a key factor in durability. Just twisting the bolt is not enough. Put a sealant on the bolt thread and around the hole on both sides of the transom. When you tighten the nuts, the sealant should protrude outward, forming a characteristic burtice, indicating that the voids are completely filled.
For reliable installation, follow this algorithm:
- ⚓ Degrease the surface of the transom in the place of drilling with acetone or alcohol.
- ⚓ Apply a layer of sealant on the back of the bracket (optional, but reliable).
- ⚓ Put bolts in the holes, abundantly lubricating them with sealant.
- ⚓ Stretching the bolts through the trench, putting on the washers and nuts, then evenly tighten.
☑️ Checklist for drilling preparations
Adjustment of the angle of inclination and depth of immersion
After the bracket is physically fixed, the angle of the emitter relative to the horizontal plane of the water should be 90 degrees static if the boat is on a flat keel. However, given the aerodynamics of the boat on the move, a slight correction is often required.
Most transom mounts allow you to adjust the angle of rotation of the sensor. If you loosen the mount nut, you can change the slope. If the sonar starts to lose its bottom at speed, try lowering the front edge of the sensor a little bit lower or increasing the depth of immersion. If the picture ripples and there are arches without fish, the sensor is probably too deep or skewed.
| A symptom. | Probable cause | Action. |
|---|---|---|
| Loss of signal at speed | Cavitation (air bubbles) | Lower the sensor below or move away from the flow |
| Noisy picture, lots of interference | Sensor too close to motor | Move the mount further away from the engine |
| Instable depth readings | Wrong angle of inclination | Level the working line strictly horizontally |
| Double echo (bottom duplication) | Too much sensitivity or angle | Reduce sensitivity or adjust the angle |
Remember, at different speeds, the boat behaves differently, and you have to do both idling and planing tests, and you make changes smoothly, literally a few degrees at a time, and you get the results.
Use a temporary wooden bar with a fixed sensor to "roll" it along the transom at different speeds before drilling permanent holes.
Cable laying and connection protection
The cable track is the circulatory system of your sonar, and it has to be laid so that you minimize the risk of mechanical damage and electromagnetic interference, and don't run the sonar cable parallel to the motor power wires or navigation lights, which are guaranteed interference.
Use special grommets to insert the cable into the knoll or the appliance. Simply drilling the hole without a seal will lead to moisture entering the hull of the boat, which can lead to rotting of the floor or corrosion of metal. The cable should be fixed with clips or screeds every 30-40 cm, avoiding sharp inflections.
⚠️ Warning: When laying cable inside a PVC boat, avoid places where it may be rubbed with passengers' feet, piels or gear. Use plastic cable channels or corrugated cables for added protection.
All connections, if they are unavoidable, must be made by soldering and heat shrinkage with adhesive layer. The twists and insulation do not live long in marine conditions. The connectors at the end of the cable should be treated with dielectric lubrication to prevent oxidation of the contacts.
System testing and troubleshooting
The final step is to test the system's performance in real-world conditions, get the boat out and turn on the sonar. In the parking lot, you should see a clear map of the bottom. If the bottom jumps or disappears, check again the angle and cleanness of the sensor's working surface.
Start at low speed. If the signal is stable, gradually add gas. The moment of signal loss will indicate a problem with cavitation or angle. In this case, go back to the adjustments. Remember, the sensitivity settings (Sensitization).Sensitivity) and frequencies (Frequency) in the menu, the sounder also affects the stability of the image.
Frequent problems and methods of their solution:
- 🛑 Screen noise: Check the grounding of the motor and the quality of the connection of the “minus” battery terminal.
- 🛑 The absence of fish in its presence: It is possible that the speed of passage is too high or the sensitivity is underestimated.
- 🛑 Unrealistic depths: Check the water speed setting (fresh/salty) in the appliance menu.
The effect of sound speed on readings
Sound speeds in salt water are faster than in fresh water, and if you've moved from river to sea and you haven't switched settings, depth readings can vary by 3 to 5 percent.
Clean the sensor regularly from fouling, mud and dirt. Even a thin layer of algae can significantly impair signal quality. Seasonal maintenance of the mount is also necessary: check the nut tightening, as vibration has the property of weakening them.
The quality of the sonar image depends on 80% of the correct installation of the sensor and only 20% of the capabilities of the device itself.
Questions and Answers (FAQ)
Can I attach the sounder sensor to the plastic transducer of a PVC boat?
Yes, you can. You can use a special bracket with wide clamping paws or suction cups to do this. It's important to ensure that the locking is rigid so that the sensor doesn't "walk" when you're excited. You can also use a 3M VHB Scotch temporal mount for testing, but you can use a mechanical clamp for permanent use.
At what height from the bottom of the boat should the sensor be?
The optimum height is the lowest possible, but with safety in mind, usually 5-10 mm below the keel line, too low will increase resistance and risk of failure when touching the bottom, and too high will lead to flow disruption and signal loss.
Why does the sonar show arcs when there are no fish?
This can be due to the wrong angle of the sensor, which causes air bubbles or suspension to be perceived as objects, and it can also be too high sensitivity or operating at the wrong frequency for a given depth.
Do I need to take off the sensor for the winter?
If the boat is stored in an unheated room or outdoors, the sensor is better removed, cleaned and stored warmly. Plastic and electronics can suffer from temperature changes and ultraviolet light. The fastening can be left if it does not interfere.
Does the paint on the transom affect the sounder?
A thin layer of antifouling paint does not affect ultrasound, but a thick layer of paint, especially with metal shavings, or a swollen coating can cause interference. The working surface of the sensor should be clean.