Garmin GDT 43 Depth/Temp Thru-Hull Transducer, For Nexus/Silva 43 mm TH43, 0-20 Deg Deadrise

Overview

The Garmin GDT 43 is a thru-hull transducer that measures water depth and water temperature for compatible marine instruments. It runs at 200 kHz, reads depths up to 275 m (900 ft.) depending on conditions, and uses a 43 mm (1 11/16 in.) thru-hull hole size with a 6 m (19.7 ft.) cable.

It also works as a retrofit for existing Nexus and Silva 43 mm thru-hull transducers (TH43), which can save time when you are replacing an older sensor and want to keep the same hull opening. The body is intended for hulls with a 0-20 degree deadrise and supports hull thickness from 6 to 42 mm (0.24 to 1.65 in.).

This is a solid match for sailboats and powerboats that want dependable depth under the keel plus water temperature on the instrument page, whether you are cruising unfamiliar shallows, fishing temperature breaks, or keeping an eye on the seabed while maneuvering in tight harbors.

Key features

• Depth and water temperature sensing in one thru-hull unit
• 200 kHz sonar with depth capability up to 275 m (900 ft.), depending on water conditions and installation
• 43 mm (1 11/16 in.) thru-hull hole size, with support for hull thickness from 6 to 42 mm (0.24 to 1.65 in.)
• 6 m (19.7 ft.) transducer cable for routing to an instrument location
• Intended for hulls with 0-20 degree deadrise
• Retrofit compatibility with Nexus and Silva 43 mm thru-hull transducers (TH43)
• NMEA 2000 network connection available when used with an NMEA 2000 adapter

Variants

This product is offered in multiple configurations based on how you want to connect depth and temperature data to your onboard system.

The sensor form factor remains the same 43 mm thru-hull style; the practical difference is whether the configuration is meant for Nexus wiring or includes an NMEA 2000 adapter for network integration.

• 010-01749-00: Version GDT 43. This version is set up for direct wiring to a compatible Nexus depth port, with cable length trimmed as needed during install.
• 010-01749-10: Version GDT 43 NMEA 2000. This version includes an NMEA 2000 adapter so depth and temperature can be placed on an NMEA 2000 backbone and viewed on compatible displays.

Compatibility and fit

Plan for a 43 mm (1 11/16 in.) hull opening and confirm your hull thickness falls within 6 to 42 mm (0.24 to 1.65 in.). The transducer needs clean, non-turbulent water flow, so placement matters: avoid areas behind strakes, intakes, discharges, or other fittings that introduce aerated water.

On fin-keel sailboats, the recommended placement is forward of the keel while staying close to the centerline; on full-keel vessels, mounting at a slight angle that aims toward the bow is preferred. On powerboats, keep it away from sharp chines and clear of prop wash, especially on single-drive setups.

Installation and setup

Thru-hull installs call for careful hole placement, proper sealing, and inside access to tighten and inspect the fitting. For cored fiberglass, the core around the penetration should be sealed before final assembly to prevent water intrusion. Use marine sealant at the flange, follow cure times, and always do an in-water leak check before leaving the boat unattended.

Electrical and system integration

For Nexus systems, the cable can be cut to length and landed on the dedicated depth port. Wire mapping is: black to black, red to blue, shield to shield, and the white conductor is not used. If the instrument does not show data on first power-up, calibration may be required in the Nexus environment.

For NMEA 2000 installations, the transducer connects through an NMEA 2000 adapter and then into the network via a drop cable and T-connector. The adapter supports 9 to 16 Vdc power input and has a maximum power consumption of 2.4 W.

Maintenance and care

Like any hull sensor, performance drops when marine growth builds up. Clean fouling with a soft cloth and mild detergent, and step up to a scouring pad or putty knife only when growth is heavy. After any cleaning or service, confirm the seal and check for leaks at the installation site.

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

Learn more.

Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

Learn more.

Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

Learn more.