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Boat Maintenance - Taking Proper Care of Your Boat

Most of us own cars and we know that maintenance is a part of owning one.  We are constantly bombarded with advertisements that tout a better or more cost effective way to keep them in good running condition.  Boats require maintenance also, but since we are not constantly reminded of it, it seems that some of us forget to maintain our boats the way we really need to.  In addition, some of the maintenance items on a boat may be a bit different than what is required for a car.  Here are some things that you need to do to keep your vessel running smoothly.

Engine and Propulsion Systems

Let’s start with one of the more obvious areas and one that is similar to your car.  First and foremost, if you have a new boat, be sure to follow the manufacturer’s recommendations for engine maintenance.  You don’t want to do anything to void your warranty.

1.        Change your oil – This should be the most obvious one.  Good, clean oil is the life of any engine.  Changing it according to the manufacturer’s recommendations is imperative, especially in boats.  Unlike cars, recreational boats are often left sitting for days or even weeks at a time between uses.  This allows for moisture and acid to build up in the engine oil.  Using cheap oil or allowing it to go too long between changes can do damage to your engine.  Even if you have not put many hours on your engine in a particular season, change the oil anyway.  Make sure that you check the engine oil periodically between changes to ensure that levels are not too low for safe operation of the boat. 

Make sure you use the right oil for your boat's engine

2.       Change your outdrive, lower unit or transmission fluid – Determining which one of these applies to you depends on whether your boat’s engine is a sterndrive, outboard or inboard but failure to keep your outdrive, lower unit or transmission fluid in good shape can lead to shifting problems at best and complete failure at worst.  Once again, using the proper lubricant and checking levels periodically between changes is recommended. 

New Impeller
If you pull your old impeller out and there are chunks missing, they could be in your engine.

3.       Cooling system – If your boat has a closed cooling system, be sure to check the coolant levels periodically and change the coolant at recommended intervals.  Worn out coolant will not be effective in cooling the engine or lubricating necessary cooling components.  For both closed and fresh water cooling systems, change the impeller every two years.  If the old impeller is missing vanes when removed, the missing pieces could clog heat exchangers in closed cooling systems so be prepared to do some disassembly to get them out.  Be sure to check the fresh water intake screen at least twice a year and clean it out.  Depending on the areas where you boat, you may find that you need to do it more often or less often but it is important to make sure that the screen remains clear so cooling water can flow freely. 

4.       Clean Flame Arrestor – That thing on top of your boat engine’s air intake is not an air filter.  It is a flame arrestor.  Since boats do not operate in conditions where dirt and dust are common, they do not require air filters but they do need a flame arrestor to help prevent ignition of fumes tat could potentially be in the engine compartment (This does not apply to outboard engines).  Flame arrestors do need to be cleaned.  Make sure you periodically remove it, and check for dirt and debris.

Typical flame arrestor, sometimes also called a spark arrestor.  

5.       Visual Check of the Engine Compartment – Even if you are not performing scheduled maintenance, it is a good idea to periodically open the engine compartment and do a visual check.  Checking things like the condition of belts and hoses, looking for signs of fluid leaks and taking note of anything unusual can go a long way in preventing issues when you are on the water. Don’t ignore or underestimate anything that you see.  Follow up and determine if it really is an issue or not.  Also, keep in mind that for boats with inboard engines, there are many other system components down in the bilge.  If you are already down there, it is a good time to check them as well. 

Electrical Systems

The boating environment can be corrosive, especially if you boat in salt water.  Electrical systems in boats are designed with this in mind, but you can still do things to help prevent problems. 

1.        Check for corrosion and clean battery terminals and other connections periodically.  Corroded terminals will cause problems delivering necessary electrical current, especially under high loads such as when starting the engine or using a windlass.  Using a corrosion resistant coating for terminals is also a good idea.

2.       Make sure you have the right types of batteries for your boat.  First of all, marine batteries are different from standard car batteries.  This does not mean that you can’t use a standard car battery in your boat but marine batteries are designed to withstand the boating environment better.  Also, when it comes to lead acid batteries, maintenance free batteries are easier to deal with but they do not last as long as those that require water to be added.  Within the marine battery category, you have several options:

a.       Lead Acid Starting Battery – This is a standard marine battery designed to start your boats engine and supply basic electrical needs such as radio and lights.  It is similar to your car’s battery but designed to handle the marine environment.  They typically do not recover fully after being fully discharged more than a few times.  They come in different sizes according to the application.

b.      Lead Acid Deep Cycle Battery – This battery is designed to provide power to accessories and/or other marine systems over long periods of time.  They are designed so they can withstand many discharge/recharge cycles before they need to be replaced.  Sometimes these are referred to as house batteries because they are used to provide power for features such as cabin lighting when shore power is not available and engines are not running.  They are also commonly used for trolling motors.

c.       Lead Acid Dual Purpose Battery – This is a combination of the Starting battery and the deep cycle battery and can be used for both purposes. 

d.      AGM Batteries – These batteries are an alternative to lead acid batteries.  They are lighter, can be discharged at a higher rate and are spill proof.  They also perform well in cold environments.  They do typically cost more than lead acid batteries and are sensitive to heat.  For this reason, they are often used as house batteries or other situations where they are not installed in engine compartments.

e.      Gel Batteries – These batteries have properties similar to AGM batteries but can be discharged at higher rates and will recover better after sitting in a discharged state for long periods of time.  They do take longer to charge and have the highest cost of all of the battery types discussed here.  They also require a charger that is compatible with gel batteries.

Know what type of battery is best for your boat and your boating habits.

3.       If you have lead acid batteries that are not maintenance free, be sure to check the water level periodically.  Allowing a battery to dry up will kill it quickly.  When adding water, be sure to use only distilled water.  Using tap water will introduce contaminants that will shorten the life of the battery.

4.       Check your navigation lights periodically.  Being out on the water after the sun goes down with faulty lighting is dangerous.  Check them often to make sure they are in working order.  Carry spare bulbs on board as well in case a bulb expires while you are on the water.  Consider converting to LED lights if you have not already done so.

5.       Check your bilge pumps.  Whether it is rain water or sea water, sometimes water gets in your boat.  Bilge pumps are designed to pump water that gets in your boat out of your boat. If the bilge pump stops working and you don’t know it, bad things can happen.  Check to ensure that they are working by first flipping that manual switch and then by checking the float switch.  Doing so will help ensure that your boat stays afloat when you are away.  Replace or fix non-working bilge pumps immediately.

Ignoring your bilge pump could lead to bad results.


Keeping the topsides of your boat clean is hard to forget because that’s the part you see every time you use your boat but what about the bottom?  A clean bottom is not only better for your boat but it can also save fuel. 
When I took delivery of my current boat, the bottom was dirty.  It had been sitting in a slip, not being used for several months before I bought it.  On my first cruise out, I took notice of some of the performance numbers.  With both engines at 3000 rpm, my speed measured by GPS was 20 mph.  The next week, I had the bottom cleaned and shortly afterward, I took it out again.  Now at 3000 rpm, my speed was 24.5 mph.  That was an increase of 22.5 percent!  Whether you experience as much of an increase as I did depends on several factors, but it is clear that it makes a difference.  Getting the bottom cleaned also provides a good opportunity for an inspection of the hull and running gear. 
A dirty bottom will use more fuel and hide problems.

If your boat stays in the water, bottom paint will eventually need to be done, especially if you are in salt water.  If you are in fresh water and your boat has never had the bottom painted, you will be able to avoid it for some time.  How long depends on the boat, but once you have had the bottom painted, you cannot go back.  Bottom paint does wear out and needs to be redone.  How long it will last depends on where you boat, how you boat and what type of paint you have.  Either way, a periodic inspection is necessary to determine when it is time to repaint.
Not only can bottom paint make your boat look nice but it protects the hull and helps keep it clean.

Change Anodes

While most of your boat may be fiberglass or wood, there are some metal parts that are in constant contact with the water.  The propeller shaft, the outdrive or thru hull fittings are all examples of metal components that are in constant contact with the water.  These metal components can be subject to galvanic corrosion if not protected properly.  On boats, this protection is implemented in the form of sacrificial anodes and they need to be inspected and changed periodically.  Failure to do so, can result in corrosion of some of the underwater components which will lead to failure. 

Check your boat to see where your anodes are and what shape they are in and replace if necessary.  Depending on your boat, the anodes may be on the outdrive, the propeller shaft, rudders or keel.  Sometimes they are also attached to the transom.  Be aware that the type of anode that you need depends on where you boat.  Magnesium anodes are typically used for fresh water, while zinc anodes are used for salt water.  Aluminum anodes can be used for both. 
This boat has anodes installed on the rudders, the bottom of the trim tabs and on the transom below the waterline.

Check Your Rigging

If you have a sailboat, periodically inspect the rigging.  This should include the following:

1.        Halyards

2.       Lifelines

3.       Turnbuckles

4.       Blocks

5.       Sails

6.       Headstay

7.       Backstay

8.       Shroud

9.       Spreaders

10.   Tiller and Rudder

Look for any abnormal wear and replace anything that needs replacement.  Remember, on a sailboat, your rigging is the equivalent of your engine.  Don’t ignore it.
Check the rigging on your sailboat periodically.

All of this maintenance may seem like a lot to do but if you set a schedule and do a little bit at a time, it really is not much at all.  Each time I visit my boat, I check something different with each check only taking a couple of minutes.  This still leaves me plenty of time to enjoy being on the water. Caring for a boat is a labor of love.  IF you take care of it, it will take care of you.

Captain Frank


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  1. Starting and trolling system batteries are very expensive. their website To make it a little simpler and keep it straight, give the batteries a number designation, such as #1, #2, and #3.

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