Boaters pre-Departure Electronics Checklist

Electronics Departure Checklist | Prevent Electronics Faults on Your Boat

Early-season electronics faults often occur due to unnoticed failures that have occurred over the period that the boat was sitting unused. This simple checklist will help you avoid those issues from ruining your trip.

This article explains how to use the TweedsMarine Electronics Departure Checklist (pre-departure checklist) and walks you through simple, step‑by‑step checks to do before leaving the dock.

It’s written for boaters who use their boat infrequently or are preparing for their first trip of the season and need a clear, low-risk routine to avoid common failures, such as dead batteries, oxidised contacts, or a non-booting device.

The printable PDF checklist is available for download by clicking the image above, allowing you to take it with you to the boat and tick off items as you go.

I know that many people do not like checklists; however, checklists are a good starting point if you are inexperienced or unfamiliar with a new boat. I don’t expect that this checklist will be usable on all boats, but it is intended as food for thought to get you started in building your own checklists.

Why this checklist matters

Idle boats develop faults. Batteries self‑discharge, terminals oxidise, and shore‑power/charger faults are common after storage. Small electrical faults turn into big problems at sea.
Simple checks prevent disruption. A few minutes of basic testing and logging saves delays, towing costs, and stress.
Designed for beginners. The steps use basic tools and plain language so people unfamiliar with marine electrics can follow them safely.

Before you start: safety and test conditions

Switch chargers/shore power off for 24 hours. If batteries are normally kept on a charger or shore power, switch the charger/shore power off for at least 24 hours before you measure resting voltages to avoid false readings.
Isolate before you touch. Use the battery isolator or master switch to make circuits safe before any hands‑on inspection.
Personal safety. Wear eye protection when handling batteries, and use an insulated spanner (wrench) when checking the battery terminals. Avoid loose clothing around the engine.
When to call a pro. Stop and contact a marine electrician if you find overheating, heavy corrosion, a strong sulphur/acid smell, or batteries that won’t accept a charge.

The checklist explained

Power and battery checks

Measure resting voltages. With chargers off for 24 hours, use a multimeter to record resting voltages for the start battery and house battery. Write the readings in your logbook. Typical healthy resting voltages: fully charged lead‑acid ~12.6–12.8 V; lower readings can indicate partial or full discharge.
Check battery condition and connections. Inspect terminals for white/green corrosion and ensure clamps are tight. Clean lightly with a marine contact cleaner and a brush if needed; re‑tighten to the correct torque. Avoid shorting terminals.
Battery selector/isolator position. Confirm the selector is in the expected position (Both/Start/House) and note it before you start the engine.
Spare fuses and fuse kit. Carry and label spare fuses that match your boat’s circuits. Replace any blown fuses before you leave.
If batteries read low. Try a controlled charge ashore or with a smart charger. If they won’t hold a charge, note this in the log and arrange further testing or replacement; flooded cells require specific gravity testing by someone experienced.

Charging system quick tests

Engine running voltage check. With the engine attended and safe, observe battery voltage while the engine runs: voltage should rise above the resting voltage (typically ~13.8–14.6 V when charging). Record the running voltage and engine RPM in the logbook.
Charger/inverter status. Inspect the inverter/charger front panel for faults or error lights and check the shore‑power inlet and cable for damage when on dock power. Turn shore power back on only after you’ve finished resting‑voltage checks.

Navigation and chartplotter checks

Chartplotter boot test. Power the unit and confirm it completes its normal boot sequence and shows a position or “no GPS” message. Wait for a stable GPS fix before casting off.
GPS fix and backups. Allow the chartplotter time to get a fix. Always carry a backup: a GPS‑enabled handheld, a tablet with offline charts, and paper charts if possible.
Data safety and charts. Keep chart media and backups separate and secure ashore; treat your electronic charts and waypoints as valuable data and back them up regularly.

Comms and personal safety electronics

VHF radio checks. Test the fixed VHF power supply, ensure that the voltage doesn’t sag when transmitting, make a radio check call to confirm transmit and receive capability; confirm a charged handheld VHF powers up and transmits. Perform a short radio check on a local working channel.
EPIRB and PLBs. Check the EPIRB or personal locator beacon status and service/battery dates and perform any manufacturer self‑test recommended for pre‑departure.
Carry power spares. Bring spare batteries for handheld VHF and a small power bank for phones and handheld devices.

Instruments, sensors and networks

Depth and speed sanity check. Confirm the depth sounder shows a plausible depth for the berth or launch ramp and that speed/log values update when you move the boat slowly. Check that the paddle wheel for boat speed/log rotates freely.
Engine gauges and alarms. When you run the engine briefly, confirm tachometer (rev counter), oil pressure, temperature, and alarm lights operate normally. Record engine hours, any anomalies, and actions taken to rectify.
Networked devices. If you have NMEA networks, power up all units from the helm and confirm each device is visible and reporting. Note any units that don’t appear and investigate.

Tools, spares, labelling and logging

Essential kit to carry: multimeter, screwdrivers, spanners for battery terminals; contact cleaner and corrosion inhibitor; spare fuses; cable ties; a small roll of electrical tape.
Label and store spares. Label fuses and switches clearly and keep spares in a dry, labelled kit. A tidy kit saves time when troubleshooting.
Record everything. Log voltage readings, running voltages, engine hours, faults found and actions taken. A simple trend log helps you spot batteries that slowly deteriorate.

Final checks before casting off

Confirm GPS has a stable fix.
Confirm VHF transmit/receive and EPIRB status.
Re‑check battery isolator position and note final resting voltages if you reconnected chargers.
Make a final logbook entry of outstanding issues and plan immediate maintenance ashore if anything is marginal.

When to get professional help

Seek a marine electrician when you encounter any of the following: persistent low battery voltages after charging, a charging system that doesn’t raise voltage when the engine runs, visible overheating or melted insulation, heavy terminal corrosion that won’t clean, or any smell of burning or battery acid. These signs can indicate a wiring fault, a failing alternator, or unsafe wiring that needs specialist tools and experience.

Downloadable checklist and next steps

The printable Electronics Pre‑Departure Checklist PDF is available for download here, so you can follow the same sequence on board. Use the checklist the first time you walk through the boat this season and start a simple log to build a maintenance history. If you find faults you’re not comfortable repairing, arrange a professional inspection before you leave the dock.

FAQ

Frequently Asked Questions

How long should I switch the charger or shore power off before testing batteries?

Switch off the charger or shore power for at least 24 hours before measuring resting battery voltages to avoid false high readings from recent charging.

What voltage shows a healthy resting 12-volt battery

A healthy, fully charged lead‑acid battery typically reads about 12.6–12.8 V at rest. Lower voltages indicate partial or full discharge and should be logged and investigated.

Can I test batteries with the engine running

Yes — a running engine is useful for a charging check. With the engine running, battery voltage should rise into the charging range (roughly 13.8–14.6 V). Do not work on electricals with the engine running and follow basic safety precautions.

I get no GPS fix on the chartplotter what should I try first

Give the unit time to acquire satellites and confirm the unit reports “no fix” or a position. Use a backup GPS device or phone app for navigation if the plotter never locks. If other networked units also lack position, check the GPS antenna feed and wiring or consult a technician.

What basic safety steps should I follow when inspecting batteries

Isolate the battery with the master switch, wear eye protection, avoid metal jewellery, and keep the area well ventilated. Call a professional if you see heavy corrosion, swelling, or detect a strong acid smell.

When is it time to call a marine electrician?

Call a professional for persistent low battery voltages after charging, charging systems that don’t raise voltage when the engine runs, melted or overheated wiring, heavy corrosion that won’t clean, or any burning smells or smoke.

What should I log after completing the checklist?

Record resting voltages, running/charging voltages, engine hours, any faults found, fuse replacements, and actions taken. Keeping these notes over time helps spot gradual battery or wiring deterioration.