Whether we like it or not, boat maintenance is essential for boat owners to keep their boats functioning properly. Here are some tips from our experts to make life easier

It may not be anyone’s favourite thing to spend their time doing, but boat maintenance is crucial for any boat owner, to ensure their boat is ready to sail safely and efficiently.

Boat maintenance takes many forms, from the major modifications you may wish to make in the off season, to small repairs on-the-go that keep your boat running smoothly.

Although we all have to act in a reactionary fashion to an extent – things do sometimes go wrong which need fixing the moment the problem rears its head – it is best to get ahead of problems and ensure the whole boat is in the best possible shape before setting off on a trip or launching for the season.

This sort of preemptive boat maintenance can seem like an ever expanding list of things which need doing, but out panel of experts are here to list some of the coming problems that can crop up onboard to give you the best chance of getting ahead of potential boat issues.

Vet wrap, the third wonder – Jayne Toyne

Vet wrap can stick to itself and is flexible, making it useful for first aid as well as repairs onboard. Credit: Jayne Toyne

Vet wrap can stick to itself and is flexible, making it useful for first aid as well as repairs onboard and boat maintenance. Credit: Jayne Toyne

They say that there’s nothing that can’t be fixed with either a can of WD-40 or a roll of gaffer tape.

Well, add a roll of vet wrap to that and you’ve got a golden triangle of fix-all tools.

For those new to the stuff, vet wrap is commonly found near horses and other large or small furry beasts that may need some sort of bandage that doesn’t stick to fur, but also clings to itself requiring no adhesive.

It comes in an array of rolled widths and really should be considered as essential in all first aid kits.

But it’s so much more useful that for solely first aid.

Anything that needs holding together flexibly; such as gluing the sole of a sailing boot back on and holding it firmly in place for a couple of hours is easy, just bing it with vet wrap.

If you’re attempting to hold back some cables or stopping cable chaff, vet wrap them.

If you want to add a bit more grip to a slippery pole or hand hold, wrap some vet wrap around it. Put a bit on the tiller extension to cushion and add grip.

If you need to strap a limb up to incapacitate it after injury, vet wrap.

Want to add a splint after it’s already been bandaged? Just vet wrap it on.

This stuff is cheap and easy to find and when you have a roll (or two) of this on board, you’ll wonder how you ever managed without it.

Lastly, if you are able to carefully roll it back up, it can be used again and again.

Check your tiller steering – Ben Sutcliffe-Davies

Make sure your emergency tiller is sound. Credit: Ben Sutcliffe-Davies

Part of your boat maintenance should include making sure your emergency tiller is sound. Credit: Ben Sutcliffe-Davies

Does your yacht have emergency tiller steering? When was the last time you checked it as part of your boat maintenance routine?

It is important to make sure everything still fits together and works correctly.

A yacht I recently surveyed had wheel steering, and the steel tube for emergency steering had completely corroded away.

Fitting shaft anodes securely – Vyv Cox

This typical anode is well fitted but too far forward to offer maximum protection to the propeller. Credit: Vyv Cox

This typical anode is well fitted but too far forward to offer maximum protection to the propeller. Credit: Vyv Cox

Shaft anodes are by far the best way to prevent galvanic corrosion between the typical manganese bronze propeller (actually a modified brass) and stainless steel shaft, probably the most common combination.

Shaft anodes will also help to prevent unwanted corrosion between the brass or bronze blades and hubs of folding or feathering propellers and the stainless pins that connect these together.

Shaft anodes are simple things, basically a short tube with rounded ends, cut in half lengthways so they can be fitted, then bolted back together onto the shaft.

Ideally anodes should be fitted close to the P-bracket but not so close that it prevents water flow through the cutless bearing. A 25mm gap is about right.

Many owners find that having fitted one at the beginning of the season, after a couple of months it has loosened so much that it rattles against the P-bracket or falls off when the bolts become completely detached. I sometimes read that applying Loctite to the bolts will prevent this, but the real answer is to fit the anode correctly.

Firstly, abrade the shaft lightly to ensure a good electrical contact. Corrosion protection relies on the transfer of electrons and this will not happen if the shaft is fouled before the anode is fitted.

Next, put the anode onto the shaft and tighten the bolts, ensuring that the spaces between the halves are equal on both sides. Now comes the critical part.

Take a hammer in each hand, at least 1lb in weight each but preferably two. Strike the two halves of the anode simultaneously with the two hammers, knocking them together.

It will now be possible to tighten the bolts some more. Keep repeating the process until the bolts can no longer be turned. Your anode is now fixed until you decide to remove it.

Out of sight but not out of mind – Dag Pike

Check gas lines onboard a boat by bending them in a tight curve to check for any cracking. Credit: Dag Pike

Check gas lines onboard a boat by bending them in a tight curve to check for any cracking. Credit: Dag Pike

Cooking by gas is still popular on yachts and any installation using gas cylinders needs careful management.

As gas is heavier than air, leaks will sink into the bilges rather than disappear into the air, so it is vital you install a gas leak detector or gas sniffer onboard.

However, it is best to stop leaks in the first place.

The gas cylinder should be in a locker that is sealed off from the rest of the boat so that any leak can only escape out into the air or through an overboard drain, which should be regularly checked to ensure it remains clear.

The cylinder needs to be well secured in the locker and no other gear should be stowed with it. When you come to inspect the gas system as part of your boat maintenance routine, it will probably be a mixture of fixed and flexible pipes.

Check the flexible pipes by bending them in quite a tight curve to see if there are any cracks. Replace the hose if there is any cracking.

Check all the connections to ensure they are tight and use a mixture of washing-up liquid and water to brush over the connections to ensure that there are no leaks.

Check your pop rivets – Ben Sutcliffe-Davies

Make sure rivets are secure. Credit: Ben Sutcliffe-Davies

Make sure rivets are secure. Credit: Ben Sutcliffe-Davies

When the mast is down it’s easy to check the pop rivets used to secure fittings or a joint.

Salt crystals get underneath rivets, especially if they are becoming loose, which can cause corrosion.

Make sure you use the right type of rivets and they are secure.

Avoid dissimilar metals touching each other; there are insulators available to help.

Check your steering cables & carry spares – Rachael Sprot

An emergency tiller will get you to shelter, where you can replace cables. Credit: Graham Snook/Yachting Monthly

An emergency tiller will get you to shelter, where you can replace cables. Credit: Graham Snook/Yachting Monthly

Steering cables are often forgotten about during routine boat maintenance.

Although most boats are equipped with an emergency tiller, you really don’t want to travel far like this.

Think of your emergency tiller as a way to get you to shelter where you can set about replacing broken steering cables before going into harbour.

Check the condition of the cables and order spares before leaving.

Clean out your bilge – Graham Walker

Regularly flushing out your bilge will make sure it stays in good working condition. Credit: Graham Walker

Regularly flushing out your bilge will make sure it stays in good working condition. Credit: Graham Walker

Have you ever noticed how much debris finds its way down into the bilge of the boat?

The bilge on our Ovni is normally totally dry so we have no need to regularly pump it out.

On one occasion we had been living aboard for about a year when we decided to flush the bilge through with fresh water. We were amazed to see how much general debris found its way to the suction head and mesh screen filter.

There was enough general gunk jamming the head that it would have compromised the bilge pump if we had needed it in anger.

We now have a routine of flushing the bilge through with fresh water every few months to clear out any debris, which also has the benefit of ensuring a regular test of the bilge pumps.

Record your engine data – Rachael Sprot

Log your settings daily to hep you gauge the state of your engine

Log your settings daily to hep you gauge the state of your engine

Some engine problems, like inefficient cooling due to a worn-out raw water pump, develop gradually over time and can go unnoticed until they become critical. The solution?

Make a note of the normal operating temperatures and pressures from your engine every day in the log book.

Once the engine is warmed up, note down the RPM, temperature, oil pressure and charging voltage; it is amazing how consistent these are until things go wrong.

Locating spares on board – Julian and Patricia Morgan

Using clear boxes makes it easier to find spares onboard. Credit: Patricia and Julian Morgan

Using clear boxes makes it easier to find spares onboard. Credit: Patricia and Julian Morgan

Long distance cruising necessitates a high level of self-sufficiency.

A large part of this is having the necessary spares to make repairs and replace broken equipment. The problem is finding the part you need when you need it.

This problem is compounded by often having to store spares in highly inaccessible regions of the boat, like in the bilge under the bed in the guest cabin.

Our solution is to catalogue all of our spares in detail in a spreadsheet describing the item (with linked photos in some cases) and where it is stored on the boat. We label our spares containers with their storage location so they go back in the right place.

We tend not to label the boxes with their contents but rather mark a box as say Sundry Spares Box 14, with the contents of that box listed in our spreadsheet.

We keep laminated printouts of the spreadsheet in our chart table in case of IT issues.

Check the propeller is seized off – Ben Sutcliffe-Davies

Ensure your propeller is properly seized off before launching. Credit: Theo Stocker

Ensure your propeller is properly seized off before launching. Credit: Theo Stocker

Before launching, make sure the propeller is correctly seized off.

It’s amazing how often at survey that I find propellers not fully seized.

Make sure the anode is right for the water you are keeping the boat in predominantly, and that the bonding is working by using a multimeter set to ohms and a resistance of less than 0.2.

Check your hatch handles – Will Bruton

Handles stuck to hatches with glue are susceptible to failure over time, as the crew is degraded by the sun. Credit: Will Bruton

Handles stuck to hatches with glue are susceptible to failure over time, as the glue is degraded by the sun. Carry out checks as part of your boat maintenance programme. Credit: Will Bruton

On a recent yacht delivery we had a nasty surprise. We were beating to windward in a stiff breeze at night and didn’t notice that a handle on the forward-facing hatch had failed, resulting in a lot of water inside the forward cabin.

The Lewmar handle was glued on to the hatch and over time, the glue had gradually degraded in the sun.

Lewmar no longer makes this catch and the retrofit replacement has a screw through to a keeper plate on the outside of the hatch, making it much more secure.

But our experience is a timely reminder to check all hatch handles to make sure they are firmly in place before setting off.

If the handle falls off, a home-made blanking plate would make a temporary fix. Credit: Will Bruton

If the handle falls off, a home-made blanking plate would make a temporary fix. Credit: Will Bruton

All the boat’s hatches had been tested by spraying freshwater over the seals; clearly a poor simulation of a big wave rushing over the topside of the boat.

It is also a good idea to protect deck fittings from damaging UV; fabric covers for hatches will dramatically increase their life. Carrying home-made blanking plates for failed hatches and portholes is good seamanship.

Consider what you could use that you already have on board to block a failed hatch from the outside quickly and easily.

Check your air filters – Harry Dekkers

Boat maintenance tip: Check your air filters for a healthy engine. Credit: Harry Dekkers

Check your air filters for a healthy engine. Credit: Harry Dekkers

My Nicholson 35 came with a 1974 Mercedes OM636 diesel engine, which runs well.

However, the air filter was almost black, caused by particles of dirt and parts from the V-belt, which was poorly aligned.

Diesel engines need a huge amount of air for combustion so regularly checking filters is a good habit to develop and should be part of your boat maintenance routine. I also replaced some of the engine systems such as the water filter and the exhaust.

I took the opportunity to add a water separator to the fuel filter and re-route the cooling water hoses, reducing the total length of freshwater hose by nearly 1m.

Carry a spare gas regulator – Graham Walker

Boat maintenance tip: Carrying a spare gas regulator could make the difference between continuing your voyage or having to turn back. Credit: Graham Walker

Carrying a spare gas regulator could make the difference between continuing your voyage or having to turn back. Credit: Graham Walker

We had just left the Galapagos heading for the Marquesas Islands in French Polynesia. We had three weeks at sea ahead of us and were making excellent progress.

After our first night at sea we tried to light the stove to make the tea. No joy.

On investigation we discovered that the gas bottle, that had been completely full the day before, was now empty. The cause was a failed regulator that had developed a leak.

On Barracuda we carry a spare gas regulator exactly matching the one in service, so it was half an hour of work to replace it, test the joints and then have the gas system back in service in time for breakfast.

We were also carrying extra supplies of gas so the loss was not an issue.

Without having the spare regulator we would have been heading back to the Galapagos Islands to try and find a replacement during COVID.

Instead we were able to enjoy one of the best sails of our lives.

Check your coupling – Theo Stocker

Boat maintenance tip: Make sure the bolts on your propeller shaft coupling are long enough. Credit: Theo Stocker

Make sure the bolts on your propeller shaft coupling are long enough. Credit: Theo Stocker

Our standard engine check includes oil levels, fuel filter, alternator belt and water strainer. It doesn’t include our shaft coupling, but it will now become part of our boat maintenance routine.

Having put a reconditioned engine in our Sadler 29 last spring, everything was running beautifully, until we suddenly lost propulsion.

The engine was still running, but the boat went nowhere. We quickly identified the problem.

There was a clear inch between the faces of the propeller shaft coupling, where there should be none.

The bolts in the shaft coupling had vibrated loose and the shaft slid aft. Luckily no damage was done, but it could have been serious.

On closer inspection, the bolts were slightly too short, and the nylon ring of the unlock nuts hadn’t fully engaged with the thread.

It now has longer bolts, new nylocks, and a drop of Loctite for good measure.

Pump vane reversing – Vyv Cox

Boat maintenance tips Vanes reverse themselves with not difficulty. Credit: Vyv Cox

Vanes reverse themselves with not difficulty. Credit: Vyv Cox

On almost a weekly basis the same question will come up on yachting forums: ‘Which way does the water pump on my yacht rotate? I am fitting a new impeller and forgot to find out first.’

Responders can spend quite some time researching workshop manuals, whereas others either guess or say it does not matter.

I decided to find out what happens in reality.

In my home workshop I had an old water pump with an impeller in reasonable condition.

I made up a dummy shaft and lever that I could rotate by hand.

I then cut a clear cover from an acrylic sheet that was one of the replaced windows on my motor-sailer.

After a quick experiment, the answer was revealed!

The impeller reverses itself very easily with little more effort than it takes to turn the impeller in either direction.

The truth is that an impeller can be installed in the pump with the vanes facing in either direction as they will line themselves up correctly as soon as the engine turns over.

Simple hack for each impeller cover release – Harry Dekkers

Wing nuts are easier to remove, especially when out at sea. Credit: Harry Dekkers

Wing nuts are easier to remove, especially when out at sea. Credit: Harry Dekkers

One of the most important systems of a diesel engine is the cooling system.

Except in exceptional situations, most of the actual cooling comes from raw water that enters the boat via a raw water strainer which we of course keep in a good and clean condition.

A second part of the system that needs attention is the impeller pump, or more specifically the impeller itself.

To be able to check and/or change the impeller we have to remove the impeller cover.

This in itself is not a difficult job but Murphy’s Law dictates that we must be able to perform this job when out at sea.

The biggest challenge when opening and closing the cover is (a) not to drop the very small bolts and (b) not to break down the head of the small bolts.

On my boat I changed the standard brass ones with stainless ones with a wing nut head and a spring ring which I tighten without using a tool to avoid damaging the brass housing.

I met Murphy and trust me, it is much easier, especially on a moving boat

Check your forestay toggle – Ben Sutcliffe-Davies

Boat maintenance Check for signs of hairline cracks or wear. Credit: Ben Sutcliffe-Davies

Check for signs of hairline cracks or wear. Credit: Ben Sutcliffe-Davies

This forestay toggle failed. You can see the clear beaching rings which indicates that it has been slowly failing for years.

There was also excessive wear to the toggle shoulders, which should have been replaced years before.

It would have been far cheaper to replace the forestay toggle rather than the final bill of £18,000 for the lost rig and sails.

Checking the toggles for forestay and caps can be difficult with the mast stepped but there will be indications of wear developing.

Look for hairline cracks or pitting in the metal or physical wear to the toggle shoulders.

Monitor drive belt wear – Vyv Cox

Boat maintenance - Visibly low drive belts in the pulleys indicate they need replacing. Credit: Vyv Cox

Visibly low drive belts in the pulleys indicate they need replacing. Credit: Vyv Cox

It goes without saying that spares of all engine drive belts should be carried, and if you do not already know how to replace them then it is well worth while buying a book that tells you how and practising with the boat ashore in winter time.

Ideally the old ones should be replaced a day before they fail, but it is not easy to tell when this might be.

This photograph shows an engine on which the water pump and alternator are each driven by their own belt.

The belts are tightened by loosening the bolts, arrowed in red, and moving the ancillaries outwards, arrowed in blue.

But, examining the photograph more closely, we can see that in each case the bolt is close to the end of the slot and cannot be moved very much further.

It might be assumed that this is because the belt has stretched in service but no, the real reason is that the flanks of the belts have worn.

It is the angled flanks of the belt that provide the drive and not, as might be supposed, the flat lower face.

Once this flat face contacts the inner diameter of the pulleys the life of the belt is very limited.

In the photo it can be seen that the belts lie well down in the V of the pulleys and removing them will almost certainly reveal the presence of transverse cracks.

These belts do not have long to go before they break.

The message is clear – monitor the wear of your drive belts and replace them when they are visibly low in the pulleys.


Enjoyed reading this?

A subscription to Yachting Monthly magazine costs around 40% less than the cover price.

Print and digital editions are available through Magazines Direct – where you can also find the latest deals.

YM is packed with information to help you get the most from your time on the water.

      • Take your seamanship to the next level with tips, advice and skills from our experts
      • Impartial in-depth reviews of the latest yachts and equipment
      • Cruising guides to help you reach those dream destinations

Follow us on Facebook, Twitter and Instagram.