Free shipping on orders over $150. Learn more
Boat Care, Compass, Fishfinder, How-To, Maintenance, Marine Electronics, Seasonal, VHF Radio, Winterizing

Marine Electronics Maintenance Guide: How to Keep Your Gear Working Season After Season

Someone completing marine electronics maintenance on the helm of a boat.

Why Marine Electronics Maintenance Pays Off

Marine electronics live in one of the harshest environments on earth: constant vibration, salt air, UV radiation, humidity, spray, and temperature extremes. A fishfinder that costs $800 and lasts three seasons due to neglect costs far more per year than one that lasts ten seasons with proper care.

More importantly, electronics that fail on the water — a VHF radio that won't transmit, a GPS that loses signal, a searchlight that won't turn on — are safety issues, not just inconveniences. Regular maintenance keeps your gear reliable when you need it most.

This guide covers maintenance tasks for every major category of marine electronics, organized by frequency so you can build a practical maintenance schedule.

General Principles for All Marine Electronics

Before diving into specific equipment, these principles apply across the board:

  • Rinse with fresh water after every saltwater use. Salt is the primary enemy of marine electronics. A quick rinse removes salt crystals before they can absorb moisture and cause corrosion.
  • Dry before storing. Moisture trapped inside housings promotes corrosion and mold. Leave hatches and covers open to allow airflow after rinsing.
  • Use UV protectant on display screens and plastic housings. UV degrades plastics and causes screens to yellow and become brittle. Apply a UV protectant (303 Aerospace Protectant is widely recommended) to all plastic surfaces seasonally.
  • Inspect connections regularly. Corroded or loose connections are the most common cause of intermittent electronics problems. A connection that looks fine visually may have significant resistance from internal corrosion.
  • Keep a maintenance log. Record what you inspected, what you found, and what you did. This makes it easy to track when items were last serviced and identify recurring problems.

VHF Radio Maintenance

After Every Use

  • Wipe down the radio face and microphone with a damp cloth to remove salt and grime
  • Rinse the microphone connector with fresh water if exposed to spray or submersion
  • Confirm Channel 16 is selected as the default watch channel before powering off

Monthly (During Season)

  • Perform a radio check on Channel 16 or a working channel to confirm transmit and receive are functioning
  • Inspect the microphone cord for cracks, kinks, or damage at the connector ends — these are high-wear points
  • Check the antenna connection at the radio — confirm the PL-259 connector is tight and free of corrosion

Annually

  • Inspect the antenna and its mount for corrosion, cracks, and UV degradation. A cracked antenna radome allows water intrusion that degrades performance.
  • Check the coax cable run for chafe, kinks, and UV damage. Pay particular attention to where the cable enters the boat and at any bends.
  • Inspect all connector seals — apply self-amalgamating tape to any exterior connections that show weathering
  • Verify your MMSI number is programmed and your DSC distress function works (test per your radio's manual — do not transmit a live distress call)
  • Confirm your GPS position is feeding the radio for DSC (check the DSC menu for a position readout)

Replacement Indicators

  • Transmit power significantly reduced (test with an SWR/power meter)
  • Cracked or yellowed display
  • Microphone that cuts out or produces distorted audio
  • Any radio more than 10 years old should be evaluated for replacement — DSC technology and radio performance have improved significantly

Fishfinder / Chartplotter Maintenance

After Every Use

  • Rinse the display face with fresh water — use a soft cloth, never abrasive materials
  • Close the sun cover if equipped
  • Eject any SD/microSD cards and store them in a dry location if the boat will sit for more than a few days

Monthly (During Season)

  • Check the display mount for tightness — vibration loosens RAM mounts and flush mount hardware over time
  • Inspect the power cable connection at the back of the unit — confirm it's fully seated and the locking collar (if equipped) is secure
  • Check transducer cable routing for chafe, particularly where it passes through the transom or hull

Annually

  • Update the unit's software/firmware — manufacturers regularly release updates that fix bugs and improve performance. Check the manufacturer's website for the latest version.
  • Update charts — Navionics, C-MAP, and Garmin BlueChart charts are updated regularly. Outdated charts can show incorrect depths, missing hazards, and wrong marina information.
  • Inspect the transducer for marine growth, impact damage, and fouling. Clean with a soft brush — do not use abrasive cleaners on the transducer face.
  • Check the transducer bracket for corrosion and tightness (transom mount) or inspect the through-hull fitting for leaks (thru-hull mount)
  • Clean the display screen with a screen-safe cleaner and apply UV protectant to the bezel and housing

Replacement Indicators

  • Screen delamination or significant yellowing
  • Touchscreen that no longer responds accurately
  • Transducer that produces consistently noisy or inaccurate readings after cleaning and repositioning
  • Unit that no longer receives software updates from the manufacturer (end of support)

Marine Compass Maintenance

Monthly (During Season)

  • Check for bubbles in the compass fluid — a bubble indicates fluid loss, usually from a cracked dome or seal. A small bubble (under 1/4") is acceptable; a large bubble significantly affects accuracy.
  • Verify the compass reads correctly by comparing to your GPS COG on a known heading
  • Check that no new magnetic items have been placed near the compass (tools, handheld radios, speakers)

Annually

  • Clean the compass dome with mild soap and water — never use solvents, which cloud the plastic
  • Apply UV protectant to the dome and housing
  • Re-swing the compass if you've added new electronics or equipment near the compass (see our deviation guide)
  • Inspect the mounting screws for corrosion and tightness

Replacement Indicators

  • Large bubble in the compass fluid that cannot be corrected
  • Compass card that sticks or moves sluggishly
  • Cracked or severely clouded dome
  • Deviation that cannot be corrected with the built-in compensating magnets

Marine Searchlight Maintenance

After Every Use

  • Rinse the searchlight housing and rotation mechanism with fresh water after saltwater use

Monthly (During Season)

  • Test full rotation (360°) and vertical tilt — confirm smooth operation with no binding or grinding
  • Test illumination — confirm the bulb lights immediately
  • Inspect the cable entry seal at the base for cracking or separation

Annually

  • Inspect and lubricate the rotation mechanism with a marine-grade grease or corrosion inhibitor per the manufacturer's recommendation
  • Check the mounting hardware for corrosion — re-torque mounting bolts if needed
  • Inspect the lens for cracks and UV degradation
  • Keep a spare bulb on board — ACR RCL-50 and RCL-100 replacement bulbs are available in our Lighting collection
  • Inspect the controller (URC-102 or URP-102) for water intrusion and corrosion at the connector

Electrical System and Wiring Maintenance

Monthly (During Season)

  • Test the bilge pump automatic float switch — pour water in the bilge and confirm the pump activates
  • Check battery voltage with a multimeter or battery monitor — a fully charged 12V AGM battery should read 12.8–13.0V at rest
  • Inspect visible wiring for chafe, particularly where cables pass through bulkheads or near moving parts

Annually

  • Inspect all electrical connections for corrosion — green or white oxidation on terminals indicates corrosion. Clean with a wire brush or electrical contact cleaner and apply corrosion inhibitor (Boeshield T-9 or similar).
  • Check fuse block for blown fuses and corrosion on fuse contacts
  • Inspect battery terminals — clean with a baking soda solution if corroded, apply terminal protector spray after cleaning
  • Test all navigation lights — walk around the boat and confirm all lights illuminate correctly
  • Test CO and propane detectors with test gas (see our CO alarm guide for testing procedures)
  • Inspect through-hull fittings and seacocks — exercise each seacock through its full range of motion to prevent seizing

End-of-Season Winterizing

For boats stored out of the water during winter, these additional steps protect your electronics during storage:

Electronics

  • Remove all portable electronics (handheld VHF, handheld GPS) and store indoors — freezing temperatures can damage batteries and LCD screens
  • Remove SD/microSD cards from chartplotters and store separately
  • Clean all display screens and apply UV protectant
  • Cover all displays with their sun covers or with a soft cloth to prevent dust accumulation
  • Disconnect the battery or connect to a battery maintainer — a quality smart charger in float mode will keep batteries healthy through winter storage

Wiring and Connections

  • Apply corrosion inhibitor to all electrical connections, fuse block contacts, and battery terminals
  • Spray connector contacts with a contact cleaner/protector (DeoxIT or equivalent)
  • Leave the battery switch in the Off position

Transducer

  • Inspect the transom mount transducer bracket — if storing on a trailer, consider removing the transducer to prevent damage from trailer rollers or straps
  • Clean any marine growth from the transducer face

Compass

  • Cover the compass dome to protect from UV during storage
  • Do not store magnets or magnetic tools near the compass during the off-season

Start-of-Season Commissioning Checklist

Before the first trip of the season, run through this checklist:

  • ☐ Test VHF radio — transmit and receive on a working channel; confirm DSC has GPS position
  • ☐ Test fishfinder/chartplotter — confirm GPS lock, chart display, and sonar function
  • ☐ Update firmware and charts if updates are available
  • ☐ Test compass — check for bubbles; compare to GPS COG on a known heading
  • ☐ Test searchlight — full rotation, tilt, and illumination
  • ☐ Test all navigation lights
  • ☐ Test bilge pump automatic operation
  • ☐ Test CO and propane detectors
  • ☐ Check battery voltage and charge state
  • ☐ Inspect all visible wiring for winter damage (rodents, moisture)
  • ☐ Confirm all fuses are intact and fuse block contacts are clean

Shop Marine Electronics and Maintenance Supplies at Egret Marine

Browse our full catalog for replacement parts, accessories, and upgrades across all your marine electronics categories:

Related Articles

Questions about maintaining or upgrading your marine electronics? Contact the Egret Marine team — we're here to help you keep your gear running reliably, season after season.

Previous Next