GST™ 43 Through-Hull Speed & Temperature Sensor

The Garmin GST™ 43 through-hull transducer is designed to provide accurate water speed and water temperature data.

No, the GST™ 43 transducer does not provide depth data. It is designed solely for measuring water speed and temperature.

Yes, the GST™ 43 transducer is designed for seamless integration into NMEA 2000® networks. For this, it requires the GST 10 adapter, which is sold separately.

Data collected by the GST™ 43 transducer can be displayed on compatible Garmin chartplotters and instrument displays, such as the GMI 10, GMI 20, GNX 120, GNX 130, and GPSMAP series.

Yes, this model is specifically designed to replace or upgrade older 43 mm Nexus through-hull transducers (TH43). This compatibility ensures a straightforward transition for existing Nexus system owners.

For the basic installation, you will need the following tools:

A drillA 43 mm (1 11/16 in) hole sawMarine sealantSilicone greaseA cable cutterFor fiberglass cored hulls, a 52 to 55 mm (2 1/16 to 2 3/16 in) hole saw is also required.

On keel-and-fin sailboats, the transducer must be mounted more than 25 cm (10 in) and less than 75 cm (30 in) forward of the keel, and within 10 cm (4 in) of the centerline.

Yes, for optimal performance, the transducer must not be mounted behind frames, stiffeners, fittings, water intake or discharge openings, or anything that could create air bubbles or turbulent water. On single-propeller boats, it must not be mounted in the propeller wash path.

If the hull is a fiberglass cored laminate, the core must be properly sealed to prevent water ingress that could severely damage the boat. This can be done using fiberglass and resin, or casting epoxy. Detailed instructions are provided for this procedure, including drilling and sealing the core.

Yes, using marine sealant is essential. It must be applied to the outer flange of the through-hull fitting before hand-tightening the nut. After the sealant has cured, the nut must be removed to apply sealant inside the hull before retightening.

Yes, the GST™ 43 transducer must be calibrated before it can be used with an NMEA 2000 network or a Nexus system to ensure optimal accuracy of speed and temperature data.

When connecting the GST™ 43 transducer to a Nexus system, you must cut the transducer cable to the desired length and connect the wires as follows:

Green to GreenYellow to YellowWhite to WhiteScreen to ScreenThe blue wire must not be used.

No, the GST 10 adapter, which is required to connect the GST™ 43 transducer to the NMEA 2000 network, is sold separately and is not included with the transducer.

Garmin’s limited warranty does not apply to the following damage:

Cosmetic damage (scratches, nicks, dents)Consumable parts (unless damage is due to a material or manufacturing defect)Damage caused by an accident, abuse, misuse, water, flooding, fire, or other external causesDamage caused by service performed by a person not authorized by Garmin

It is recommended to keep the plug supplied with the transducer. It can be used when cleaning or servicing your depth sounder, providing temporary protection for the through-hole.

Yes, if the transducer is not installed in a suitable location or is not mounted correctly, it can cause cavitation. Cavitation can degrade the boat's performance and potentially damage the propeller.

The transducer must be mounted parallel to the fore-aft axis of your vessel. Additionally, the through-hull fitting must be installed with the pin at a 90-degree angle to the centerline of the boat for correct orientation.

Garmin recommends that this equipment be installed by a qualified marine installer. This ensures optimal performance of the transducer and prevents potential damage to your boat.

On powerboats and hulls with pronounced chines, the transducer should not be mounted near the edge of the chines. It is important to choose a location where the water is clean and non-turbulent.

Yes, the Garmin GST™ 43 through-hull transducer is specifically designed to replace or upgrade older 43 mm Nexus through-hull transducers (TH43). This compatibility ensures a straightforward transition for owners of existing Nexus systems.

To connect to a Nexus system, you will need to cut the GST 43 cable to the desired length and connect the wires according to the following diagram:

GST 43 Green connects to Nexus Green
GST 43 Yellow connects to Nexus Yellow
GST 43 White connects to Nexus White
GST 43 Screen connects to Nexus Screen
The GST 43 Blue wire must not be used with a Nexus system.
For integration into an NMEA 2000® network, the GST 43 transducer connects via the GST 10 adapter (sold separately).