Garmin GT36-TM and GT8HW-IH transducer pack

The Garmin GT36-TM and GT8HW-IH transducer pack is designed to be compatible with Garmin chartplotters. For specific compatibility with your chartplotter model, consult your device manual or Garmin’s compatibility information.

Using a pack combining a transom-mount transducer (GT36-TM) and an in-hull transducer (GT8HW-IH) provides versatile sonar coverage and several advantages:

Versatile detection: The transom-mount transducer excels with ClearVü and SideVü imaging, while the in-hull transducer is ideal for traditional depth readings, even at high speeds.Maximum protection: The in-hull transducer is shielded from impacts with underwater objects or during launch/towing, as it is installed inside the hull.Reduced drag: The in-hull transducer creates no drag or turbulence, which can benefit boat performance.Adaptability: This pack allows selecting the best transducer for different navigation conditions or specific needs (e.g., an in-hull transducer for depth at high speed and a transom-mount transducer for detailed imaging at lower speeds).

For optimal placement of the GT36-TM transducer on the transom, consider the following points:

It must be mounted parallel to the waterline. It must extend 3.5 mm (0.125 in) below a fiberglass hull or 10 mm (0.375 in) below an aluminum hull. Mount it as close as possible to the centerline of the transom, but at least 38 cm (15 in) from the propeller. Avoid mounting it behind strakes, reinforcements, fittings, water inlets or outlets, or anything that could create air bubbles or turbulence. If your propeller rotates clockwise, mount the transducer on the starboard (right) side. If it rotates counterclockwise, mount it on the port (left) side to avoid the propeller wash. The transducer must be in clean (non-turbulent) water for optimal performance.

To minimize interference and optimize your transducers' performance, follow these guidelines:

Turbulence interference: Mount transducers away from anything that can agitate the water, such as propellers, strakes, steps, through-hull fittings, water intakes or discharges, and hull irregularities. Turbulence typically forms in the direction of the propeller's rotation.

Electromagnetic interference (EMI): Route transducer cables away from ignition wires, batteries, engines (including trolling motors), high-energy wires (radar, audio amplifier, autopilot pump). If a transducer cable must cross a power cable, do so at a 90-degree angle. Installing a ferrite bead on the transducer cable can also help.

Acoustic interference: Avoid mounting transducers near other transducers (if they operate on the same frequency), ship machinery, or areas prone to wind, wave, or rain noise. If using multiple transducers, space them at least 60 cm (24 in) apart if they share the same frequency.

Yes, it is possible to extend the GT36-TM transducer cable if the original length is insufficient to reach your display. Garmin offers dedicated extension cables (Garmin part numbers 010-11617-42 or 010-11617-32).

However, to avoid signal degradation, it is recommended not to extend the cable beyond 9 meters (30 feet). It is critical not to cut the transducer’s original cable, as this would void the warranty.

The Garmin GT36-TM and GT8HW-IH transducer pack is a complete solution for your sonar system. It combines a transom-mount transducer (GT36-TM) for external detection and an in-hull transducer (GT8HW-IH) for maximum protection, providing versatile sonar coverage.

Choosing a pack with both types of transducers offers great versatility. The transom-mounted transducer (GT36-TM) ensures optimal performance in direct contact with water, while the internal transducer (GT8HW-IH) is protected inside the hull, reducing risks of external damage and drag. This combination allows for effective detection in various conditions and installation preferences.

The GT8HW-IH internal transducer is mounted inside the hull, meaning it does not require drilling through the hull and is less prone to external damage. It creates no drag or turbulence and is ideal for towed boats. It is recommended for solid fiberglass hulls.

The pack includes the GT36-TM and GT8HW-IH transducers, their respective mounting kits (for transom and internal installation), as well as the associated fasteners required for installation.

The GT8HW-IH internal transducer is recommended for installation on solid fiberglass hulls only. It must not be mounted on metal, wood, or sandwich hulls (with core material).

The GT8HW-IH internal transducer can be installed on solid fiberglass hulls with a maximum thickness of 16 mm (5/8 in).

For the GT36-TM transom-mounted transducer, select a location parallel to the waterline. It must be mounted as close as possible to the centerline of the transom, at least 38 cm (15 in) from the propeller. Avoid areas behind frames, struts, fittings, water inlets or outlets, or any other source of turbulence. If your propeller rotates clockwise, mount the transducer on the starboard (right) side; if it rotates counterclockwise, mount it on the port (left) side.

To reduce interference, mount the transducer away from sources of electromagnetic noise (engines, power cables, other electronic devices) and from turbulence zones created by the hull or propeller. Routing the transducer cables away from power cables, or crossing them at 90 degrees if necessary, can also help. If using multiple transducers, space them at least 60 cm (24 in) apart to avoid acoustic interference.

No, cutting the transducer cables is strongly discouraged. Cutting the transducer cables usually voids the product warranty and may degrade the signal quality. If the cable is too short, specific Garmin extensions can be used, but it is recommended not to exceed 9 m (30 ft) of extension to avoid signal degradation.

For installing the internal GT8HW-IH transducer, you will need the following tools:

A #1 Phillips screwdriver220-grit sandpaperHigh-quality marine-grade adhesive suitable for the hull materialAntifreeze for RV/boat or mineral oilRubbing alcohol

Yes, if your boat spends a lot of time in the water, it is recommended to apply water-based antifouling paint to the GT36-TM transducer and its mounting hardware. This helps prevent marine growth and maintains the transducer’s performance. Do not use acetone or acetone-based products, as they will damage the transducer’s plastic housing.

To test the location, place the transducer in a thin plastic bag filled with water to cover the bottom of the transducer. Wet the hull surface at the chosen location, then place the bagged transducer on the hull. Check the transducer output on your display. If performance is not optimal, select a new location and repeat the test.

This transducer pack is compatible with Garmin chartplotters. For specific compatibility with your Garmin chartplotter model, consult the user manual or Garmin’s website.