Boat Maintenance Part 1
The Real-World Guide to Boat Maintenance: What Actually Matters for Power and Sail
Boat maintenance has gotten complicated with all the product marketing and conflicting advice flying around. As someone who has kept both power and sail vessels running for over a decade, I learned everything there is to know about what actually needs doing — and what’s just noise. Today, I will share it all with you.
Here’s the truth: proper maintenance isn’t glamorous, but it’s the difference between a boat that takes you where you want to go and one that leaves you calling SeaTow. I’ve seen both sides of that coin, and I’ll take the weekend spent doing oil changes over the weekend spent waiting for a tow every single time.
Engine Maintenance
Your engine lives a hard life. Saltwater environment, vibration, heat, and humidity — marine engines deal with conditions that would destroy a car engine in a season. Regular oil changes are non-negotiable. I do mine every 100 hours or once a year, whichever comes first. And I mean marine-specific oil, not whatever’s on sale at the auto parts store. The additives are different for a reason — marine oils are formulated for the wet, corrosive environment your engine sits in.
Check your oil before every single outing. It takes thirty seconds and it’ll catch problems before they become catastrophic. I found a blown head gasket early once just because I noticed the oil level creeping up and looking milky. Saved me an engine rebuild.
Cooling System
Probably should have led with this section, honestly. Impeller failure is one of the most common and most preventable engine emergencies out there. Those little rubber impellers in your raw water pump degrade over time, and they absolutely hate being run dry — even for a few seconds. I replace mine every spring as a matter of routine, and I keep a spare plus the gasket in my parts bin aboard. The day you need one and don’t have it will be the day you’re fifty miles from the nearest marine supply store.
After every saltwater run, flush the engine with fresh water. I know it’s tedious when all you want to do is tie up and crack a beer, but the salt crystals that form in your cooling passages will slowly strangle your engine’s cooling capacity. A quick flush prevents that entirely.
Fuel System
Water in your fuel is not a matter of if but when. Condensation happens, fuel docks aren’t always pristine, and ethanol-blended gas is hygroscopic — it literally pulls moisture out of the air. That’s what makes water-separating fuel filters so critical for us boaters — they’re your engine’s last line of defense against moisture damage.
I swap my filters at the start of every season and check the collection bowls every few trips. If you’re storing the boat for more than thirty days, treat the fuel with a quality stabilizer. Old fuel turns to varnish, and cleaning that out of injectors or carburetors is neither fun nor cheap.
Hull Maintenance
The hull is literally the thing keeping water on the outside. Give it some respect. Bottom paint prevents marine growth — barnacles, slime, grass — that increases drag and kills your fuel economy. Down here in warmer waters, you can see growth start within weeks of a fresh bottom job. I haul out and repaint annually, and I’d recommend the same for anyone south of the Chesapeake.
Waterline stains are more than cosmetic. Let them sit and they’ll work their way into the gelcoat permanently. A quick wipe-down after each trip keeps things looking sharp and prevents long-term damage.
Fiberglass Care
UV is the silent killer of fiberglass boats. The sun breaks down gelcoat slowly but relentlessly, turning a glossy hull chalky and porous over time. Wax or ceramic coating provides a barrier — I’ve switched to ceramic myself and the longevity is worth the extra cost up front. Hit scratches and dings as soon as you spot them. Water gets into exposed fiberglass and starts the delamination process, and once osmotic blisters start forming, you’re looking at professional repair bills that’ll make your eyes water.
Electrical Systems
Marine wiring is a whole different animal from household wiring. Everything corrodes. Salt, moisture, and vibration are constantly working against your connections. I go through my electrical panel and accessible connections once a season with a can of dielectric grease and a sharp eye. Green fuzz on a terminal isn’t just ugly — it’s adding resistance that generates heat and wastes power.
Test your batteries monthly. Capacity drops over time, and a battery that reads full voltage but can’t hold a load under draw is worse than useless — it’s deceptive. And make sure your grounding system is solid. Stray current corrosion from bad grounding can eat through underwater metals faster than you’d believe.
Safety Equipment
This is the stuff nobody wants to spend money on until they need it, and then they’d pay anything. Check your PFDs — buckles jam, zippers corrode, and foam eventually loses buoyancy. Expired flares are both useless and illegal. I set a phone reminder every year to check dates and replace what’s expired. Fire extinguisher gauges should be in the green; give them a visual check monthly. If you have an EPIRB, test it per the manufacturer’s schedule. When you’re 200 miles offshore is not the time to discover your emergency beacon doesn’t work.
Seasonal Tasks
Fall winterization and spring commissioning are the bookends that protect your investment. Winterize everything — engines, freshwater systems, heads, all of it. Water expands when it freezes, and a cracked engine block or burst hose will ruin your whole spring budget. Cover the boat properly to shield it from UV and keep moisture and critters out.
Come spring, go through every system before you launch. Run the engine on muffs, test electronics, cycle through seacocks, inspect hoses and clamps. I keep a commissioning checklist that I’ve refined over the years, and it catches something every single time.
The Bottom Line
Maintenance isn’t the exciting part of boat ownership — nobody posts their oil change on Instagram. But it’s the part that keeps the exciting parts happening. Small problems caught early stay small. Small problems ignored become big, expensive, potentially dangerous problems. Build a schedule, stick to it, and your boat will give you years of reliable, safe time on the water. That’s the deal, and I think it’s a pretty good one.
Part 2: Advanced
Taking Boat Maintenance to the Next Level: Advanced Care for Serious Cruisers
If you’ve got the basics down, good — you’re already ahead of most boat owners. But for those of us who spend serious time aboard or venture further from shore, there’s another tier of maintenance that separates weekend warriors from confident cruisers. Let me walk you through what I’ve learned the hard way.
Engine Maintenance — Going Deeper
Beyond basic oil changes, start paying attention to trends. Keep a log of oil consumption, coolant levels, and operating temperatures. An engine that starts using more oil than usual is telling you something. Same with coolant — if the level keeps dropping and you’re not seeing external leaks, you might have an internal issue that’s cheap to fix now and expensive to fix later.
Compression tests every couple of years give you a real picture of engine health. It’s the kind of thing most people don’t bother with until something goes wrong, and by then the information is academic.
Cooling System — Advanced
If you’re running in warm tropical waters, heat exchangers need attention beyond basic impeller swaps. Scale builds up on the raw water side and reduces cooling efficiency. I pull my heat exchanger every other year for cleaning. It’s a messy afternoon job, but it keeps operating temperatures where they should be. Also, keep an eye on zinc anodes inside the exchanger — they protect against galvanic corrosion, and a spent zinc means your heat exchanger body is next on the corrosion menu.
Fuel System — Advanced
For long-range cruising, fuel quality management becomes mission-critical. I carry a fuel polishing system that circulates and filters fuel in the tanks. After sitting in a Caribbean marina for a few weeks, you’d be surprised what grows in diesel fuel. Biocide treatments help, but they’re no substitute for actual filtration. Sample your fuel periodically — a clear jar and some patience tells you a lot about what’s in your tanks.
Hull Maintenance — Beyond the Basics
Underwater metals need attention too. Prop zinc anodes, shaft zincs, and hull zincs all sacrifice themselves to protect your running gear. Check them regularly and replace at 50% depletion — don’t wait until they’re gone. I’ve seen propellers eaten alive because an owner thought the zincs “looked fine” from the dock. Get in the water or hire a diver.
If you’re hauled out, take the opportunity to check cutlass bearings, shaft alignment, and rudder bearings. A slight vibration underway could mean a bearing that’s on its way out, and catching it on the hard saves a haul-out later.
Fiberglass Care — Advanced
For older boats, consider having a moisture survey done. A surveyor with a moisture meter can identify areas of water absorption that aren’t visible to the eye. Addressing high moisture readings early — through drying and barrier coating — prevents the kind of structural issues that can make a boat unseaworthy or unsellable.
Electrical Systems — Advanced
Invest in a battery monitor that tracks state of charge, current draw, and charging history. Flying blind on your electrical system is how people end up with dead batteries at anchor. I installed a Victron monitor three years ago and it completely changed how I manage power aboard. You start to see patterns — which systems draw more than expected, when your charging sources aren’t keeping up.
Wiring inspections should include checking for chafe where wires pass through bulkheads or near moving parts. One chafed wire in the wrong spot can start a fire, and boat fires are absolutely nothing to mess around with.
Safety Equipment — Advanced
Go beyond the minimum. A properly stocked abandon-ship bag, a PLB for each crew member, and regular man-overboard drills turn safety from a checklist item into genuine preparedness. I run through emergency scenarios with my crew at the start of every offshore passage. It feels silly until it doesn’t.
Seasonal Tasks — Advanced
Consider a professional survey every five years, even if you’re not buying or selling. A fresh set of expert eyes catches things you’ve gotten used to seeing. I had a surveyor find corrosion in a chainplate that I’d walked past a thousand times. It would have become a rig failure eventually. Worth every penny of the survey fee.
The Bottom Line
Advanced maintenance is really just basic maintenance done more thoroughly, more consistently, and with more attention to what your boat is telling you. Every noise, every smell, every slight change in performance is data. Learn to listen to your vessel and she’ll take care of you out there. That’s what makes this whole maintenance routine endearing to us passagemakers — it’s the foundation of the trust between you and your boat.
