Top 9 Easily Avoidable Boating Breakdowns

Throughout the years of inspecting and repairing boats, I’ve noticed a trend of common breakdowns and issues that could’ve been avoided with proper preventative maintenance, and some basic inspection before boating.

#1 Wheel Bearings

Worn Boat Wheel Bearings

You’ve all seen the trailers parked on the side of the M1 heading up the coast come holiday time. This is a holiday nightmare. Consider this – you’ve got the whole family in the car and a holiday destination booked. You’ve just battled through peak holiday traffic and you’re busting to get there and relax. Finally, the traffic finally eases and you’re doing 110km/hr, when smoke starts bellowing out of your trailer wheels. You pull over, and realise the bearings are cooked. Now you’ve got to either:

  1. Repair them yourself,
  2. Leave the boat where it is and come back, or
  3. Order a tow truck.

Depending on the size of the boat – this can be one of the biggest hassles known to man. You’re now going to miss a night of holidays, or get there a lot later than planned.

How can this be avoided?

A simple inspection of each wheel bearing should be carried out before a long trip. Often, repair shops forget unless you mention you’re going away – so don’t be shy to let your repairer know at your next service.

Take a look behind your wheels and bearing caps – if they look like a ball of rust, you need to revaluate your trip!

#2 Flat Batteries 

Everyone has done it before – packed the boat up and forgot to switch the isolator off, left the shore power lead out, or left the depth sounder on. If your boat lives on a mooring it can be worthwhile getting a decent solar system fitted, one that has provisions to trickle charge each battery individually so you keep all the batteries in top shape.

Basic battery maintenance includes cleaning the terminals, ensuring the water levels are topped up to the correct level and charging if left unattended for 3-6 months at a time.

Boat batteries can often be in awkward spots to change, so ensuring they’re kept charged is much easier than replacing or jump starting every outing.

#3 Bellows Failure


Bellows are a hidden part, that as an owner you will unlikely see – unless the boat is out of the water and you go looking. They are designed to keep the water out whilst also being flexible as the drive unit moves around.

Each year when your boat is serviced ask for the bellows to be inspected. If there is any doubt of the condition, it’s best to replace them. Keep tabs on when they were changed as over time the rubber becomes hard, which will eventually lead to a tear or failure. Where possible, always keep the drive trimmed down when not underway, as the bellows will not be constantly stretched and will result in a longer lifespan. Damaged bellows that go unnoticed almost always convert to a sunken boat.

#4 Alternator Failure

Every modern boat has a voltmeter fitted to the dash, and this will show you if your alternator is charging. A voltmeter takes a reading of battery voltage – so you know when they are being charged. With the engine off (with your ignition switch on), your battery voltage will be anywhere from 11.5v to 12.8v. With the engine running and alternator charging it should be 13v or higher. If your alternator is not charging your trip will be limited to how much battery is stored, and once it runs out your engine will likely stop running – this is because modern engine electronics require power to run, telling the engine when to fire, how much fuel to inject and even what position the throttle is in.

Please note: On larger diesel-powered boats – you may come across a 24v system. In this case, the numbers are double – you will have between 23v and 25.6v with the engines off, and 25.6v and 28v with the engines running.

#5 No Steering

Depending on the steering type, the most common failures are either no steering, or seized steering.

Hydraulic steering has rubber seals to stop the oil from escaping, and with age they deteriorate. Before a big trip it’s a good idea to pop the fill cap at the helm to see if the fluid is low. If the fluid is low, this means it’s escaped in the system somewhere and there is likely a leak. The two most common places to find a leak would be at the steering ram and behind the helm/s.

If you find your steering is seized – it is more likely you have a mechanical type. The steering arm at the back mounted through your outboard – and this can build up with dried up salt. Most manufacturers install a grease nipple which needs to be greased every service –  and ensuring you hose down the rear of the outboard after each trip will help prolong the life.

#6 Leaking Sea Pump

A leaking sea pump, while it won’t stop you from operating the engine (most of the time), can cause havoc in your engine room.

Every brand of inboard engine will have a water pump, which is designed to circulate sea water around the engine to cool it. They have seals which can wear out over time and leak water. Depending on where the pump is situated on the engine, sometimes it can circulate down onto the pulleys and get sprayed around the engine room – corroding the front of the engine and alternator. Pictured above is a typical scenario where there is a stain below the engine due to water being sprayed around in the bilge. Getting a leak fixed as soon as it happens should be treated with urgency and is important step in avoiding problems. When left too long it will cause the inevitable – a break down, usually in the form of a dead alternator or faulty sensor.

#7 Tight To Shift Gears

Over time, cables originally fitted will wear out and become stiff or stretched. If left unattended to, they eventually break – then you’ve lost control of your engine. If it happens at the wrong time it can be the difference between parking safely and crashing into another boat. Imagine you’re reversing into your berth and you go to put it into forward, but the cable has snapped, leaving it stuck in reverse. You’re now heading towards the berth (or other boats) with no means of stopping the momentum.

Best way to avoid this happening to you? Inspect the cables visually for any obvious exterior damage – but usually you won’t be able to see much and a better indication is feel. If the cable is beginning to get tight or miss gears – don’t wait for it to snap – get it replaced!

#8 Overheating

We’ve all heard that dreaded engine alarm once in our boating life. You’re headed to your favourite spot at full throttle, and the alarm starts squealing. A quick check of the dash confirms the temperature light is on. The best ways to avoid an overheat are:

  • Replace your manifolds and risers at the correct service intervals
  • Replace your impellers at the correct service intervals
  • Cleaning your closed loop cooling system at the correct intervals (heat exchangers/aftercoolers/wet exhaust elbows etc. approx. every 5 years)
  • Regularly flushing your engine if stored out of the water
  • Inspect your thermostat. Your mechanic can check it with a few bolts and a gasket(most cases). The thermostat will open when dropped into a bucket of boiling water – confirming it is still good.

Seems like a lot to check? It’s definitely better than breaking down in bad weather.

 #9 Contaminated Fuel

You only use your boat a few times a year, but can you remember when fuel was last put in? Having fresh fuel at the correct octane, clean, and water free is one of the best ways to avoid getting stuck. The diesel fuel filter pictured below is full of dirt with a portion of water – which can be drained from the screw down the bottom. Not all fuel filter have this feature, but if you get the option for a sight glass it’s a good idea.

Some boat manufacturers even go one step further and install a sensor that alerts you on the dash if the fuel has water mixed together.

Regularly changing your fuel filters and getting rid of old, stale fuel is vital step for trouble free boating.

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