Repair & maintenance guides

How to Use an Oil Extractor Pump for Boat Oil Changes

Change engine oil cleanly through the dipstick tube with a manual or electric extractor: know which engines it suits, warm the oil first, get as much out as you can, then refill to the dipstick, recycle the old oil and clean the pump so it's ready next time.

How to Winterize (and Recommission) Your Boat's Freshwater System

Protect the tank, pump, water heater, faucets and showers from freeze damage with non-toxic antifreeze, then flush and sanitize everything in the spring so the water is clean again. A cracked pump or split fitting is a common, avoidable winter repair bill.

How to Winterize a Marine Diesel Inboard (Sailboat or Trawler)

Lay up a marine diesel for winter the way the engine makers describe it, covering fresh oil, a full and treated fuel tank, antifreeze through the raw-water side, the impeller out, the coolant checked, openings plugged and the battery cared for. Freeze damage to a diesel's raw-water circuit is one of the most expensive and most avoidable winter repairs.

How to Winterize a Marine Generator (and Recommission It in Spring)

Lay up an onboard diesel or gasoline generator for winter with fresh oil, treated fuel the way your maker specifies, antifreeze through the raw-water side, the impeller out, the start battery cared for and the intake and exhaust sealed, then bring it back safely in spring. A generator's raw-water circuit freezes just like a main engine's.

How to Wire a Bilge Pump Correctly (Automatic Float, Panel Switch and Fuse)

Wire your bilge pump so the automatic float works even with the battery switch off, the helm switch gives you a manual override, and every circuit has the right fuse, wire size and connections kept above the bilge water. A pump that is wired wrong can leave the boat unprotected exactly when nobody is aboard.

How to Wire a Marine Stereo, Speakers and Amplifier Safely

Install or fix a boat stereo the way that keeps it working and keeps your battery alive: marine-rated gear, a fused feed from the panel, a solid ground, a plan for the always-on memory wire, UV-proof speakers, and an amplifier fused right at the battery. Plus how to stop the stereo from messing with your VHF and compass.

How Water Gets Into Boat Fuel (and How to Stop It)

Water in the fuel is one of the top causes of rough running and dead engines, and it almost always has an entry point you can find. Work from the jar test through the fill cap O-ring, a recessed deck fill, the tank vent, the sending unit gasket and your washdown habits, and learn how much condensation really matters.

Hull Blisters (Osmosis): How to Tell Cosmetic Pimples From Serious Pox

Learn what osmotic blisters are, how to inspect a fiberglass bottom at haul-out, which blisters you can fix yourself with epoxy, what moisture meter readings can and can't tell you, and when to hire an independent surveyor.

Hull Potential Survey: Checking Corrosion Protection with a Reference Electrode

A silver/silver-chloride reference electrode and an ordinary multimeter show whether your underwater metals are really protected by their anodes, whether every fitting is bonded, and whether shore power or the slip is upsetting things. Learn how to take the readings, what under- and over-protection mean in plain terms, and when to call a marine electrician or corrosion specialist.

Ice Makers and Drinking-Water Dispensers on Boats: Cleaning, Filters and Winterizing

Keep onboard ice and drinking water clean and tasting good. Sanitize and descale the ice maker, change filters, keep the condenser breathing, fix common faults, and drain and bypass everything before freezing weather.

Impressed Current Corrosion Protection on Yachts: How It Works and How to Keep an Eye on It

Larger aluminum and steel yachts often use an impressed current system instead of, or alongside, sacrificial anodes. Learn what the control panel, anodes and reference electrodes do, how to log and double-check the readings with a portable reference cell, why over-protection can strip paint and attack aluminum, what to do at haul-out, and when to call a corrosion specialist.

Inboard and Sterndrive Engine Mounts: Signs of Failure and How to Inspect Them

The rubber mounts under an inboard or sterndrive engine soak up vibration and hold the engine in line with the drive. Learn the warning signs of a failing mount, how to inspect all of them in under an hour, and why a mount replacement always ends with an alignment check.

Inflatable Boat and Dinghy Care: Cleaning, UV Protection, Leaks and Storage

Keep your inflatable or RIB tender holding air for years. Rinse and clean it the right way, protect the tubes from sun, check pressure with a gauge, find slow leaks with soapy water, service the valves, patch small holes with the correct glue for PVC or Hypalon, and store it clean and dry.

Inflatable Life Jacket Care: Inspect, Test and Rearm

An inflatable life jacket only saves a life if the cylinder is full, the inflator is armed and the bladder holds air. Learn the quick check before every trip, the overnight leak test, how to read replacement dates and how to rearm it after it fires.

Inheriting a Boat: Title Transfer, Coast Guard Documentation, Insurance, Taxes and Keep-or-Sell

What to do when a boat comes to you from a relative's estate: secure it and keep it insured, find out how ownership passes (joint owner, transfer-on-death, probate or a small-estate affidavit), transfer a state title or a Coast Guard documented vessel, deal with the trailer, liens and taxes, and decide whether to keep or sell. General information, not legal or tax advice.

Installing a DC-to-DC Charger: Charging a Lithium or Second Battery Bank from Your Engine

A DC-to-DC charger lets the engine's alternator refill a lithium (or separate) house bank with the right charge profile while protecting the starting battery and the alternator. Learn why you need one, where it can and can't be mounted, how the fusing and cable sizing work, and which settings matter, so you can plan the job or check a technician's work.

Internet Near Shore: Cellular Routers, Signal Boosters and Marina Wi-Fi Extenders

For boats that stay within sight of land, a cellular router, a legal signal booster or a marina Wi-Fi extender can be a cheaper alternative to satellite. Learn which one fits how you boat, why antenna placement and cable length matter, the FCC rules for boosters, how much power they use and how to test that it actually works.

Is My Engine Charging the Battery? Test the Charging System With a Multimeter

A step-by-step way to find out whether your outboard's stator and rectifier/regulator or your inboard's alternator is really charging the battery, what the voltage readings usually mean, and when the problem is just a dirty connection. Exact test specs come from your engine's service manual.

Is My Vehicle Rated to Tow This Boat? Towing Capacity, GCWR and Tongue Weight Explained

The towing number in the ad is only one of several limits. Learn which ratings matter (towing capacity, GCWR, GVWR, axle and tongue limits, hitch class and ball rating), how to weigh your real rig at a truck scale, and when you need trailer brakes and towing mirrors.

Isolation Transformer vs. Galvanic Isolator: Which Does Your Boat Need?

Understand how a galvanic isolator and an isolation transformer each protect a boat on shore power, when the heavier, pricier transformer is worth it (stray-current marinas, aluminum boats, liveaboards), and what to ask the ABYC-certified electrician who installs it.

Keeping Chartplotter Charts and Software Current (Garmin, Raymarine, Simrad, Lowrance, Navionics, NOAA)

Old charts can show buoys that moved and shoals that grew. Learn how chart subscriptions and updates work across the big brands, where NOAA's free charts fit in, how to handle SD cards safely, how to back up your waypoints and routes before anything goes wrong, and a simple yearly routine.

Lake Engine Restrictions: Two-Stroke Bans, Horsepower Limits, Electric-Only and No-Wake Lakes

Some lakes ban older two-stroke outboards, cap horsepower, allow only electric motors, or make the whole lake no-wake. Learn the common types of rules (with dated real examples like Lake Tahoe and Ohio's lake list), how to tell what kind of engine you have, and how to check before you tow the boat three hours to a ramp you can't use.

Launch Day and Haul-Out Checklist for Trailer Boats

A step-by-step checklist for getting your boat off the trailer and back on again safely and quickly, from the drain plug and tie-downs to the blower and ramp etiquette. Following it in order prevents the classic mistakes that sink boats and back up the ramp.

Life Raft Care: Service Intervals, Hydrostatic Releases, Mounting and the Grab Bag

A life raft you can't launch or that won't inflate is worse than none, because it gives false confidence. Learn how often rafts need professional service, how to pick a service station, when to replace the hydrostatic release, where to mount a canister or stow a valise, the checks you can do yourself, and what belongs in the grab bag instead of the raft.