Raymarine ST600/B120 Speed & Temperature Through-Hull Transducer, For Analog Instruments, Bronze, Retractable, 45 ft Cable

Overview

The Raymarine M78716 is a bronze through-hull speed and temperature transducer for Raymarine analog instrument systems. It measures speed through the water and water temperature from a low-profile hull fitting, making it a practical replacement or upgrade for boats running compatible Raymarine instrument displays.

The unit uses a 2-inch bronze through-hull fitting and a 15 m cable, equal to 45 ft, with ISO female spade connectors. It is suitable for fiberglass and wood hulls, which makes it a common fit for sailboats and powerboats where a bronze fitting is preferred below the waterline.

This is an instrument transducer, not a CHIRP fishfinder transducer. It is built for speed and temperature data on compatible Raymarine systems, including i40 Speed, i50 Speed, iTC-5, ST60, ST60+ Speed and legacy analog instruments.

Key features

• Bronze through-hull speed and temperature transducer for Raymarine instrument systems.
• Low-profile hull fitting helps reduce drag compared with taller external fittings.
• Retractable core allows access for cleaning and maintenance when marine growth affects paddlewheel readings.
• 2-inch through-hull installation size for compatible fiberglass and wood hulls.
• 15 m cable, equal to 45 ft, supports routing from the bilge or hull area to the instrument location.
• ISO female spade connectors for connection to compatible Raymarine analog instrument wiring.
• Works with compatible Raymarine analog instruments such as i40 Speed, i50 Speed, iTC-5, ST60, ST60+ Speed and legacy systems.

Compatibility and fit

This transducer is a good match for boats that need speed-through-water and water temperature data rather than GPS speed alone. It is especially useful on sailboats where true wind calculations, performance sailing data and current-aware navigation depend on accurate water speed input.

Before ordering, confirm that the existing instrument system accepts this analog speed and temperature transducer style and that the hull material is fiberglass or wood. For ST70-style installations, a compatible speed pod or interface may be required between the transducer and the instrument network.

Installation and setup

The M78716 installs through the hull and requires a 2-inch hole. The 45 ft cable gives enough reach for many typical runs from the hull fitting to the display or interface location, but routing should be checked on the boat before installation, especially on larger vessels or where cable paths must avoid machinery spaces.

As with any below-waterline fitting, installation should follow proper marine sealing practice and be placed where the transducer has clean water flow while staying clear of turbulence from strakes, intakes, keels, propellers and trailer bunks. The retractable insert is useful for seasonal cleaning, since paddlewheel speed readings can be affected by fouling.

Use cases on board

This transducer suits owners maintaining Raymarine ST60 and related analog instrument systems, as well as boats using i40 or i50 speed instruments that need a bronze through-hull sensor. It is also useful for sailboats that rely on speed-through-water data for trim, polar performance and wind calculations.

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.

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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.

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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.

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