Installation of the sonar sensor on the PVC NDND boat: a guide

Buying a fisherman sonar is only half the battle. The main technical challenge faced by an inflatable vessel owner is to install a converter (sensor) safely and reliably. High-pressure inflatable floor boats (HPD) have their own design features that distinguish them from classic plywood models or rigid aluminum hulls.

Unlike plywood, where the sensor is often attached to a transom or paiole, in NDND, the bottom is a single inflatable structure, which imposes serious limitations on installation methods, since it is absolutely impossible to drill cylinders or the bottom, and an error in choosing a location or method of fixation can lead not only to the loss of expensive equipment, but also to an emergency on the water.

In this article, we will discuss all the nuances of installation, mounting schemes and the effect of the sensor on the hydrodynamics of the vessel. The right installation strategy will allow you to get a clear picture of the bottom relief and not worry about the integrity of the boat during active planing.

Features of the design of the NDND and the choice of installation site

High-pressure inflatable boats require that the cylinders and the bottom are under considerable pressure. Any mechanical damage to the shell is depressurized. That's why classic methods like through-the-trash mounting or using suction cups on board work poorly or don't work at all. You need to find a compromise between the quality of the sonar signal and the safety of the vessel.

The main problem when installing on the NDND is the absence of a rigid plane in the aft, the bottom smoothly passes into cylinders, and the transom is often rounded or shifted inward. Perfect place. The transition zone from a solid floorboard (if you have one in your model as a removable stove) to an inflatable floor, or a special platform on the transom, if it is provided by the design, is considered to be the transition zone, but most fishermen are forced to look for solutions for mounting directly on the inflatable elements.

There's a common misconception that you can just put a sensor on the bottom of a boat, which is a mistake, because the sounder doesn't pass through the air layers and reinforced layers of layers. off-boardAny attempt to seal it inside the body will cause noise and the device will be completely inoperable.

⚠️ Attention: Never attempt to pierce the tank or bottom of a NDND boat to install a "dead" sensor. Even the use of special sealants for PVC does not provide 100% guarantee at constant cyclic stress of the material on the water.

When choosing a location, you should also consider the operation of the outboard motor. Vibration from the engine transmitted to the transom can cause severe interference on the sonar screen. Therefore, attaching directly to or near the motor bracket is undesirable. It is optimal to move the sensor away from the diametric plane, but not too close to the board to avoid trapping air when rolling.

Methods of fastening: from temporary to stationary

Fishers and accessories manufacturers have developed several basic methods for fixing the transducer on inflatable boats. The choice of the particular method depends on whether you are willing to drill the boat (which we do not recommend), how often you plan to remove the sensor, and what your budget is.

The most common and safe method is the use of universal These structures cover a transom plate or a cylinder without disturbing its integrity. Modern bracket models are equipped with adjustable hinges that allow the radiator to accurately set the angle of inclination relative to the water surface.

• 🔧 transom brackets: They're attached to a rigid transom board if it's out of the dimensions of the cylinders, they require a flat area.
• 🎈 Inflatable platforms: Special mini-cylinders made of strong PVC that are attached to the sides or bottom, and the sensor is mounted on the platform, which is the best option for maintaining driving performance.
• 🧲 Magnetic holders: They work only in pairs with metal elements of the boat (a rarity for PVC) or require the use of a weighted substrate lowered overboard on the cable.
• 📌 Heel glue: Some craftsmen stick a small area of fiberglass or hard PVC on board, and they attach a sensor to it, and they require skills in working with PVC and adhesives.

Special attention should be paid to the method of gluing the sensor directly to the cylinder through a sealant layer. Although technically possible using two-component polyurethane adhesives, this method makes the sensor non-removable. If the emitter is damaged or the boat needs to be replaced, there will be serious difficulties, and the adhesive can react chemically with the material of the balloon, weakening its structure over time.

For those who value mobility, mechanical-locked removable suction pod systems are a great solution, but they don't hold well on the rough surface of NDNDT cylinders, and the solution is to install a small, smooth squirting pad, which is already attached to the holder, which allows you to quickly remove equipment after fishing and transport the boat assembled without fear of damaging the fragile sensor.

⚠️ Attention: When using adhesive techniques or setting up sites, make sure the adhesive used is compatible with your boat's material (PVC or Haipalon). Aggressive solvents can "eat" the fabric.

The effect of the sensor on driving performance and speed

PVC NDND boats have excellent hydrodynamics, but any foreign body submerged in water creates resistance. The sonar sensor, especially if it is mounted on a long barbell or a massive platform, can significantly impair the behavior of the vessel on the water, which is especially critical when going into sleeving.

The main problem is cavitation If the sensor is too high or at the wrong angle, it creates an air bubble as you dial up speed, and the sonar starts to "lose the bottom" by showing chaotic depth figures or shutting down completely, and the excess resistance of the water in the stern can "tighten" the boat's nose, making it difficult to get on plane mode and increasing fuel consumption.

To minimize the negative effect, you need to minimize the dimensions of the fastening system. The bulky brackets that stick out under the bottom, act as a brake anchor. Ideally, if the sensor is "shut" in a streamlined casing and located in an area where the flow of water is laminar and does not break off from the edges of the cylinders.

There is a perception that a transom sensor has a greater impact on speed than a bottom sensor. In practice, for inflatable boats, the difference is minimal if the correct geometry is used. The main thing is that the emitter does not create vortices that then fall under the bottom of the boat, creating additional vibration.

When moving against a wave, an improperly installed sensor can act as a battering ram, receiving strong shocks, which threatens not only the device itself, but also damage to the balloon against which it will be beating. So, when crossing speed in bad weather, it is often recommended to temporarily raise the sensor above the waterline, if the mounting design allows.

Instructions: step-by-step installation on the transom plate

Consider the most reliable and popular option for NDND boats, which is to mount on a rigid transom board on the outside, which provides a stable signal and a sufficiently strong mount, provided that the transom has sufficient area.

First, you need to determine the installation point, which should be at least 30 cm from the engine's lower unit to avoid cavitation bubbles from the propeller, and you should also step away from the corners of the transom, so that when mooring or docking, you do not damage the sensor.

Then there's the physical installation process. If you use a through fastener (which is only permissible for a rigid plywood or aluminum transom insert, but not for a balloon!), you need to drill the hole and use a sealant. However, for NDNDM, it's more likely to use clasps. They are fixed by bolts that come together on both sides of the transmolation board, clamping it like a vise.

It is important to set the angle correctly. The surface of the emitter should be parallel to the surface of the water when the boat is on the water without a load (or with a normal load), This often requires experimenting by changing the angle of inclination of the bracket by 2-3 degrees and checking the sounder on the move.

Parameter	Recommendation	Criticism
Inclination angle	Parallel to the bottom	High.
Distance from motor	Min 30 cm.	Medium
Depth of immersion	10-15 cm from water	High.
Type of fastener	Stainless steel	High.

Once the bracket is fixed, the sensor is installed, and the cable must be immediately secured with screeds or tape along the side or transom so that it does not dangle and fall into the screw. A loosely hanging wire is a risk of hooking the driftwood or damage during transportation.

Cable protection and electrical safety

The sonar cable is the weakest link in the system, and in an inflatable boat, it is subjected to constant friction against the side, ultraviolet light and salt water, and an incorrect gasket can short-circuit or break the signal at the most inopportune moment.

To protect the cable, it is recommended to use a corrugated tube or a special cable channel, this is especially true in places of inflection, for example, at the entrance to a boat or at a transom. gufras prevents rubbing of insulation against rough PVC fabric and sharp edges of fittings.

The cable insertion into the cockpit of the boat (if the head unit is installed inside) should be sealed. If you use a boat with an inflatable floor, often the cable is simply thrown over the side. At this point, the fabric is subjected to maximum stress. To avoid damage to the cylinder, use soft pads or special treads for hoses.

Keep in mind electrical safety. All connections must be securely insulated. In high humidity and salt water, even microscopic baring of the wire will lead to electrolysis and rapid breakdown of the contacts. Use shrink tubes with adhesive layers for maximum tightness.

Maintenance and preparation for winter storage

Operation of the sonar in an inflatable boat requires regular maintenance. After each fishing, especially in salt water, the sensor and cable must be washed with fresh water. The salt crystallizes and can damage the radiator coating or corrode metal parts of the fastener.

When preparing the boat for winter storage, the sensor should be removed if the mounting design allows it. Prolonged tension of the cylinder material at the mounting point of the bracket can cause scuffing or deformation. If you can't remove the sensor, relax the tightening of the bolts to relieve static stress.

Store the sensor in a dry place, at room temperature. Sharp temperature changes can lead to condensation inside the transducer housing. The cable should be coiled into a ring with a diameter of at least 20 cm, so as not to damage the inner structure of the veins.

What if the sensor stops showing depth?

Often the problem is not the sensor itself, but the oxidized contact or the broken cable. Call the multimeter integrity lived. If the cable is intact, try connecting the sonar to another power source. If that didn't work, it may have failed the electronics due to impact or moisture.

Check the condition of fasteners regularly, vibration on water can unwind even well-tightened nuts. Loctite) a mandatory requirement for all bolts on the bracket.

Frequently Asked Questions (FAQ)

Can I put a sounder sensor directly on the boat?

Theoretically, you can use two-component polyurethane adhesive and special surface preparation (cleaning, degreasing). However, this is risky: you damage the protective layer of the balloon, and when you dismantle it, there will be a trace. In addition, the elasticity of the balloon when inflated / blown out can over time disrupt the adhesive seam.

Why does the sonar lose its signal at speed?

It's likely that air (cavitation) is being hit by the sensor because of the wrong angle of installation or too high positioning, and it could also be caused by the engine propeller's air capture if the sensor is too close to the lower unit, and try lowering the sensor deeper or changing the angle of inclination.

How long is the cable enough for a PVC boat?

The standard cable length (usually 6-9 meters) is usually enough for mounting on a transom. However, if you plan to put the sensor on your nose or use an extension cord, make sure that the build-up does not lead to loss of signal. For sonars with scanning frequency above 200 kHz, the cable length is critical.

Does the transom mounting damage an inflatable boat during transportation?

If the bracket is hard and massive, it can damage the balloon when blowing or packing the boat into a bag. It is recommended to remove the sensor with the bracket before packaging or use soft protective covers at the contact points of the metal with PVC.