Aluminum is a highly conductive material that poses unique challenges in the installation of navigational electronics. Unlike fiberglass or PVC, metal creates a “screen” that blocks ultrasonic waves while also being a source of electrical noise. Proper installation of the sensor The transom or bottom of Kazanka or Voronezh requires careful planning to avoid dead zones and interference on the screen.
Errors in installation often lead to the fact that the device shows chaotic numbers or does not see the bottom at shallow depths. transducer (the emitter) must be submerged in water at a certain angle and at a sufficient distance from cavitation bubbles formed when the propeller moves, and in this article we will discuss all the nuances that will help you get a perfect picture of the terrain and fish.
Before you start, it's important to decide what type of mounting you want, because it's not just the quality of the signal, it's also the safety of your boat. You can't just drill an aluminum case without the consequences, because the moisture will quickly get to the metal, causing corrosion. transom-mountingInstallation in the housing or use of a remote sensor is a critical stage of preparation.
Selection of sensor type and installation location
The first step is to choose the right equipment that is compatible with your operating conditions. transducerwhich are attached from the outside to the back wall, or end-to-end modelsEach option has its own advantages and disadvantages that must be weighed before buying.
Trans mounting is the most popular and least invasive method, and you don't break the sealing of the body, which is very important for aluminum, but at high speeds, it can catch air if the flow of water breaks off the transom. The optimal distance from the sensor to the longitudinal axis of the keel is at least 30-40 cmTo avoid turbulence from the screw.
If your boat is primarily used for trolling at low speeds, the trawler option is ideal. For high-speed planing boats, it is better to consider installing a special fairing or using a sensor that drops below the bottom level, which will ensure stable contact with water even in sharp maneuvers.
When choosing a location, also consider the length of the cable. Standard 6-7 meters may not be enough if the head unit is installed at the cockpit and the sensor is on board. sonar He'll get lost.
Required tools and materials
You can't get good installation without the right tools. Aluminum is a viscous material, and it requires a different approach than wood or plastic, and pre-prepared components will save you time and nerves during the installation process.
You will need the following set of tools and supplies:
- 🔧 A drill or screwdriver with a set of metal drills (cobalt or titanium coated) for careful drilling of holes.
- 🔩 A set of stainless steel (A4) fasteners or brass to avoid electrochemical corrosion with the boat hull.
- 🧪 A degreasing agent (acetone or white spirit) and adhesive soil for surface treatment before sealing.
- 🧵 High-quality marine sealant (polyurethane or silicone) with high elasticity after drying.
Pay special attention to power tools. To lay the wiring inside the aluminum side, you often have to drill bulkheads. step-drillto make neat holes under the corrugated or cable channel, without leaving sharp edges that can damage the insulation of the wire.
Don't forget the multimeter, which is used to check circuit integrity and control voltage in the onboard network, and power failures are a common cause of electronics failures on the water.
☑️ Installation tools
Trans-Trans preparation and marking
The installation process begins long before the first drilling, the surface of the transom must be perfectly prepared, aluminum often has an oxide film and factory paint, which reduces the adhesion of the sealant, and if you don't properly prepare, water will eventually penetrate the mount.
Wash and degrease the installation site thoroughly. White Spirit Or a specialized degreasing agent. Don't use gasoline, because it can leave a greasy film. After degreasing, it's advisable to lightly hide the contact point with P200-P400 grain sandpaper to create microroughness for better grip.
Marking is a step where you can't go wrong. Put a sensor mounting plate on a transom and mark the centers of future holes with a pencil. It's important to keep horizontal: the sensor should hang strictly parallel to the bottom, and even a few degrees of distortion will cause the sensor to fly out of the water when it comes out to plane.
⚠️ Warning: Do not drill holes in or near welds (less than 2 cm) and the aluminum in the seam zone has a changed structure and can crack under load or vibration.
Use the level to check the horizontality of the markings. Also consider the angle of inclination of the transom. If it is heavily lit back, you may need to make a paddle (liner) of textolite or plastic to align the working surface of the sensor relative to the water horizon.
Sensor installation and sealing
The most critical thing is the physical installation. If you've chosen a trench sensor that can be adjusted, make sure that the pivot mechanism is running freely. Before you finally lock, apply the sealant not only to the fasteners, but also to the back of the mounting pad.
Procedure for installation:
- Apply a layer of sealant on the prepared surface of the transom with a thin layer.
- Drill the holes on the markings. Immediately after drilling, treat the edges of the hole with anticort or soil, as a fresh slice of aluminum immediately begins to oxidize.
- Apply the sealant on the screws and insert them into the holes on the inside (if the design permits) or smear the hats from the outside.
- Set the sensor and tighten the nuts. Don't pull! Aluminum is soft, and excessive force can warp the transom or rip the thread.
The technology is different for in-hull sensors, where the sensor is glued into the body with a special gel or epoxy resin that does not contain air bubbles, air is the enemy of ultrasound, and the space inside the side should be perfectly flat and cleaned from paint to metal (unless the sensor instruction requires otherwise).
Nuances of end-to-end sensors
Through-hull sensors are often confused with in-hulls. Through-holes require drilling through and have a threaded body that is sealed on both sides. Internals are simply glued to the bulkhead. For aluminum boats, through-mounting is risky because of corrosion, so more often use transom or in-house options if the design of the board allows (there is a flat area without seams and ribs of rigidity).
Once installed, let the sealant dry completely. The polymerization time is indicated on the package and is usually 12 to 24 hours. Don't rush the boat into the water - moisture trapped in the unfrozen sealant will destroy the compound in the future.
Wiring laying and interference protection
An aluminum boat is essentially one large conductor and antenna, and the onboard net, the outboard ignition system, and even the movement of water, create electromagnetic tips. sounder showed a clean picture, the wiring must be performed in compliance with the rules of screening.
The power cable should be laid separately from other wires, especially from the wires to the running lights or fuel pump. Use a corrugated pipe (channel cable) for mechanical protection. In places through bulkheads, install rubber bushings so that the sharp edge of aluminum does not cut the insulation from vibration.
Use only tinted copper terminals to connect. Direct contact of copper and aluminum in the presence of moisture (condensate) causes rapid galvanic corrosion. All connections inside the boat must be securely insulated with adhesive shrinkage.
| Type of interference | Source | Elimination |
|---|---|---|
| Vertical stripes | Engine running, spark plugs | Wire shielding, engine mass check |
| Jumping depth figures | Cavitation, air intrusion | Depth of the sensor, change in the angle of inclination |
| Low-deep noise | Body reflection, splashes | Sensitivity setting (Gain), spray-driven installation |
| Signal loss | Bad contact, oxidation. | Checking terminals, using contact lubricant |
Be sure to install a fuse in the break of the sounder's power supply line. The fuse's value should correspond to the current consumed by the device (usually 1-2 Ampere), which will protect your boat from fire in the event of a short circuit.
Use ferrite rings (filters) on the sounder power cable if you notice motor interference, a cheap and effective way to improve signal quality.
Adjustment and calibration on water
The first launch is better done afloat, at a shallow depth (2-4 meters), which will allow you to quickly adjust the position of the sensor. Turn on the device and let it warm up for a couple of minutes. Pay attention to the width of the beam: a narrow beam gives a more detailed picture, a wide one - better view.
The main setting for the adjustment is sensitivity (Gain or SensitivityIf it's too high, the screen will be filled with noise and chaotic arcs. If it's too low, you won't see fish or the bottom will be blurred. Find a balance where the bottom is shown in a clear red (or orange) stripe, and the individual objects are visible above it.
Check the speeds at different speeds. Accelerate the boat to the planned speeds. If the screen shows white vertical stripes or the picture disappears, then the sensor captures air bubbles, in which case you will need to lower the sensor lower or install an additional fairing.
⚠️ Attention: Don't adjust sensitivity to the maximum depth. Start in shallow water where the signal is strong, then test the operation at depth. Excessive amplification in shallow water can blind the device.
It is also worth experimenting with the regime. Impediment filter Noise Rejection: In calm water, you can turn it off for maximum detail, and in the wave or in high winds, turning on the filter will smooth the picture, making it more readable, although some of the finer details will be lost.
Maintenance and winter storage
Aluminum is susceptible to corrosion, especially in contact with other metals and salt. Regularly check the condition of the sensor fasteners. If you notice white coating (oxides) around the screws, they must be cleaned and reprocessed with a protective compound.
Before putting the boat in winter storage, be sure to remove the sensor if possible, or wash it thoroughly with fresh water. Salt deposits and dirt can corrode the plastic body and impair the signal's passability next season. Cable carefully folded, avoiding clamps.
Check the sealant's condition. It may have lost elasticity or microcracked during the season. Refurbish the sealant layer if necessary. It's a simple procedure that will save you from having to repair the transom in the spring.
Regular check of tightness of fasteners and condition of cable is a guarantee of long service of sonar and safety of aluminum hull of the boat.
Frequently Asked Questions (FAQ)
Can I stick a sounder sensor inside an aluminum boat?
Theoretically, it's possible, but it's complicated. Aluminum conducts sound well, but the bottom of the boat usually has ribs, seams and bumps. Ultrasound won't pass through the air cushion. To glue the sensor on the inside, you need to find a perfectly flat patch without seams, clean it to metal, and use a special acoustic gel that leaves no bubbles. Most often, it's easier and more reliable to use a transom mount.
Why does the sonar lose its bottom at speed?
This is called cavitation. Under the bottom of the boat, air bubbles form that disperse the ultrasound, and the sensor sees these bubbles instead of the bottom, so the solution is to lower the sensor below the bottom level, change the angle of the tilt, or move it to a place with a more laminar flow of water.
Do I need to remove the sensor when washing the boat with a kerkerker?
Yes, high-pressure jets can damage the sensor's sensitive element or disrupt the sealing of the mounts, and the aggressive chemistry in detergents can corrode the plastic of the case, and it's better to unscrew the sensor while washing.
Does the thickness of the aluminum bottom affect the sounder?
For transom sensors, no, they work outside. For in-hulls, yes. Too thick metal (more than 10-12 mm) can weaken the signal, but it's not usually critical. The main thing is that there are no air gaps between the sensor and the metal.