Repair & maintenance guides

12-Volt Boat Wiring Basics: Circuits, Color Codes, Fuses and Wire Size

Learn how your boat's 12-volt system is laid out, what the ABYC wire colors mean, how fuses and breakers protect the wiring, why voltage drop and tinned wire matter, and how to read a wiring diagram, so you can troubleshoot smarter and know which jobs belong to a marine electrician.

Adding USB and 12V Outlets to Your Boat: Fusing, Wire Size and Placement

Phones, tablets and handheld radios need charging on every trip. Learn how to add a dedicated USB or 12-volt outlet the right way: choosing a quality marine socket, picking the wire size and fuse, deciding between a panel circuit and a direct battery feed, sealing the hole, and checking that the charger doesn't put noise on your VHF.

AIS on Your Boat: Receiver vs. Class B, MMSI Programming, Antennas and Checking You're Seen

Choose between a receive-only AIS and a Class B transponder, get the MMSI programmed the legal way, sort out the GPS and VHF antenna (or splitter), confirm other boats and the Coast Guard actually see you, and understand silent mode and AIS man-overboard beacons.

Battery Goes Dead While the Boat Sits - How to Find a Parasitic Drain

If your boat battery is flat every time you come back, something may be quietly drawing power while you are away. Learn how to tell a bad battery from a drain, find the circuit with a multimeter and the fuse panel, and fix the usual culprits without disabling your bilge pump.

Battery Isolators Compared: Diode, ACR, Combiner and DC-DC Charger

Learn what the box between your engine and your batteries actually does, why an old diode isolator can leave batteries never quite full, and which charging setup suits an outboard, an inboard or a lithium house bank, plus a simple meter check of the one you have.

Battery Monitors with a Shunt: Installing, Setting Up and Reading State of Charge

A voltmeter can't tell you how full your house battery really is. Learn how a shunt-based battery monitor counts every amp going in and out, where the shunt goes on the negative side, which settings to change for lead-acid or lithium, and how to read the percentage without being fooled.

Boat Bonding System Explained: How to Inspect Bonding Wires, Through-Hulls and Anodes

Understand what the green bonding wires on your boat do, how they tie through-hulls, running gear, tanks and engines to your anodes and DC negative, how to inspect and test the connections yourself, and which corrosion warning signs mean it's time for an ABYC-certified technician.

Boat Inverters and Inverter/Chargers: Sizing, Safe Use and What a Pro Must Install

An inverter turns battery power into 120-volt household current, which makes it as dangerous as shore power and a serious fire risk if it is fused or wired wrong. Learn how to size one realistically, what a safe installation looks like, the owner checks to do, and the mistakes (like backfeeding) that hurt people.

Boat Spotlights and Searchlights: Care, Wiring Checks and Using Them Without Blinding Anyone

A good spotlight helps you find markers, moorings and debris at night and signal for help, but only if it works and you use it carefully. Learn how to care for remote-control searchlights and handheld spotlights, clean lenses, check fuses and wiring, and use the beam in short sweeps that never blind other boaters.

Charging a 24V or 36V Trolling Motor Bank: Onboard Chargers, Charging While You Run, and Solar

A 24- or 36-volt trolling motor bank only lasts if every battery in it gets fully charged. Learn how multi-bank onboard chargers handle series banks, how alternator and DC-to-DC chargers top up the bank from the outboard, where solar fits, what changes with lithium, and the wiring habits that keep it all safe.

ELCI Retrofit: Adding Whole-Boat Shock Protection to an Older Boat

What an ELCI (equipment leakage circuit interrupter) is, why ABYC now requires one on new boats with shore power, what a retrofit involves and costs, and what to do when one trips. You plan, test and troubleshoot; an ABYC-certified marine electrician does the wiring.

Electric Linear Actuators on Boats: Kicker Lifts, Towers, Hatches, Tables and Seats

Electric actuators raise kicker brackets, fold wake towers, lift engine hatches and move tables and helm seats. Learn how they work, why water and side load kill them, how to fuse and test one directly on 12 volts, and how to replace one safely.

Electronics That Reset or Shut Off When You Start the Engine: Finding and Fixing Voltage Sag

If your chartplotter, fishfinder, VHF or stereo blinks off or reboots when you crank the engine or switch on a big load, the cause is almost always low voltage reaching the device. This guide walks from the cheapest checks (battery, connections, grounds) to the real fixes: a dedicated electronics feed, start isolation between batteries, and voltage-stabilizing converters.

Fish Finder Settings: How to Tune Your Sonar for a Clearer Picture

Get more out of your fish finder by setting frequency, gain (sensitivity), range, contrast, color palette and noise filters on purpose instead of leaving everything on auto, plus how to set the depth offset and track down interference from other electronics.

Fuse Keeps Blowing? How to Troubleshoot a Boat Fuse Block or Breaker Panel

Work through a blown fuse or tripping breaker the safe way: confirm it, tell a short from an overload, isolate the device or wire at fault, replace a worn breaker or panel switch with the same rating, and label every circuit, without ever fitting a bigger fuse.

Galvanic Isolator: Why Shore-Powered Boats Need One and How to Tell If It's Working

A galvanic isolator (or an isolation transformer on bigger boats) keeps stray DC current from the marina's ground wire from eating your anodes, drive and running gear, without cutting the safety ground. Learn what it does, the owner-level checks you can do, what failure looks like, and why the actual meter test is usually a job for a marine electrician.

How to Care for Boat Solar Panels, Connectors and the Charge Controller

A boat solar setup is quiet and almost maintenance-free, but salt, shade, loose connectors and a wrong battery setting quietly cut its output or hurt the batteries. Learn the cleaning, inspection and controller checks to do each season, and how to leave the system for winter.

How to Choose, Install and Maintain an Onboard Battery Charger

Pick the right marine charger for your batteries (how many banks, how many amps, flooded, AGM or lithium), mount and fuse it safely, set the charge profile, and use it to keep batteries healthy all season and through the winter. The AC (shore power) side is a job for a marine electrician.

How to Find and Fix Corroded Electrical Connections on a Boat

Track down the green crust and loose terminals behind flickering lights, dead gauges and slow cranking with a simple voltage-drop test, then remake the connection the marine way: tinned wire, a proper crimp, adhesive-lined heat shrink and a protective coating.

How to Find and Fix LED Lights That Interfere With Your VHF and AIS

Some LED bulbs and fixtures put out radio noise that quietly drowns weak VHF calls, DSC alerts and AIS targets. Run the Coast Guard's squelch test, track down the noisy light with a handheld radio, and fix it with distance, filtering or a quieter fixture.

How to Install a Bow-Mount Trolling Motor

Mount a bow-mount trolling motor so it stows and deploys cleanly and stays put: pick the right shaft length and spot, check clearance in every position, through-bolt it with backing, consider a quick-release bracket, and wire it with the breaker, wire size, plug and voltage the motor maker specifies.

How to Install and Set Up Forward-Facing (Live) Sonar

Mount a live sonar transducer such as Garmin LiveScope, Lowrance ActiveTarget or Humminbird MEGA Live on your trolling motor or a pole, give it clean power, route the cable so it survives stow and deploy, and dial in the basic settings. Most "bad picture" and "dead transducer" problems trace back to one of these steps.

How to Replace Boat Battery Cables the Right Way

Swap corroded, cracked or undersized battery cables for tinned marine cable sized from a chart for its real length and load, with crimped lugs, adhesive heat shrink, terminal boots, solid support and a fuse close to the battery.

How to Replace Marine Speakers (Including Tower Speakers)

Pick replacement speakers that fit the cutout, match your stereo or amplifier's power and impedance, survive sun and spray, and don't throw off your compass. Then wire them with the right polarity and seal them so water can't reach the back.