Overview

The Garmin 010-00958-00 is a black box sonar module that puts CHIRP/spread-spectrum sonar on your Garmin Marine Network so you can view returns on a compatible Garmin chartplotter or MFD. It runs on 10-35 VDC, covers 25-250 kHz depending on the transducer, and supports sounder power from 25 to 3,000 W RMS.

It can run two transducers at once using its dual-transceiver architecture, which helps on boats with multi-transducer layouts or when you want independent sonar operation at the same time. Maximum depth is rated up to 10,000 ft (3,048 m) depending on transducer choice and water conditions.

The enclosure is fully gasketed and water resistant to IEC 60529 IPX7, with a size of 274 x 373 x 100 mm (10.8 x 14.7 x 3.9 in.). Power usage is up to 100 W and the recommended fuse is 10 A.

Key features

• Outputs sonar data over the Garmin Marine Network for display and control on a compatible Garmin chartplotter or MFD
• Dual-transceiver design supports simultaneous and independent transducer operation
• Frequency range 25-250 kHz (transducer dependent) for traditional sonar and CHIRP/spread-spectrum transducer setups
• Sounder power rated 25-3,000 W RMS (dependent on transducer rating and depth)
• Maximum depth rating up to 10,000 ft (3,048 m), dependent on transducer, water salinity, bottom type, and conditions
• 10-35 VDC input for 12 V and 24 V systems; draws up to 100 W and uses a 10 A fuse
• Fully gasketed aluminum and steel housing with IPX7 water resistance; compass-safe distance 60 cm (23.6 in.)
• Operating temperature range from -15 to 70 C (5 to 158 F)

Installation and setup

Mount the module in a location where it cannot be submerged and where it has ventilation around the case. Leave enough clearance to route and service the power lead, the marine network cable, and the transducer wiring at the terminal block.

Keep the power run clean and protected with the specified 10 A fuse, and plan cable routing away from heat sources and moving parts. Maintain the 60 cm compass-safe distance when choosing a mounting spot and routing cables near sensitive instruments.

Compatibility and system integration

The GSD 26 sends sonar over the Garmin Marine Network and relies on a compatible Garmin display for control and on-screen views. A transducer is required, and the results you see depend heavily on matching the transducer type and power rating to the hull, typical depths, and bottom conditions you fish.

Transducer connections terminate on the internal terminal block, and the module supports common CHIRP/spread-spectrum wiring layouts, including single-element and dual-element arrangements. Taking time to verify wire mapping and strain relief before final tightening helps avoid intermittent sonar performance later.

Use cases on board

This module fits boats that already run a Garmin Marine Network display and want a dedicated sounder with headroom for deeper water work. It also suits multi-transducer installations where two independent sonar sources need to be available at the same time.

What's included

• GSD 26 main unit
• Power connection cable
• Marine networking cable (6 ft)
• Mounting hardware
• Software refresh SD card
• Documentation