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Apr 15, 2023

Leaking boat: how one sailor traced the source

When Alan England’s Moody 376 developed an unexplainable leak, he used

When Alan England's Moody 376 developed an unexplainable leak, he used detective work to find the source... but it wasn't easy

Credit: Jake Kavanagh

Leaking boat: how one sailor traced the source

Boats have many problems and my Moody 376 Linga Linga was not going to miss out.

Many of these occur in the bilges, which are out of sight but should never be out of mind!

It was early in 2020 that I had my first indication I had such a bilge problem, when my lower level bilge alarm went off in the middle of the day, though fortunately while the boat was safely alongside its berth in Malta.

Bilge alarms normally go off in the middle of the night or when sailing (if you have an emergency) so I had much to be thankful for.

Linga Linga at anchor in Rinella Bay, Malta. Credit: Alan England

My first action was to switch off the alarm and then inspect the main bilge, where I discovered the appearance of water.

This immediately set off the brain's panic alarm, for I’m allergic to finding water inside my boat.

The immediate problem was initially solved by the removal of about two litres of water.

Normally when you have a problem leak to solve on a boat it's raining the proverbial cats and dogs.

However, in my case Murphy's Law was activated and I had to wait a few weeks before we enjoyed a torrential downpour to enable me to carry out further investigations.

I then ‘scientifically’ ascertained whether it was freshwater or seawater by tasting it, something not normally recommended.

This confirmed that the problem was freshwater – not as serious as the salty kind, but still a problem.

So, the source had to be found and then eliminated. Sounds easy? Wrong!

Finding the source of a water leak on a boat is like finding the source of the river Amazon, something that I believe is still under dispute.

I decided to follow the approach of that great detective, Sherlock Holmes, and be methodical.

Luckily, the leak occurred when Linga Linga was alongside her permanent berth in Malta. Credit: Alan England

The first step was to remove all traces of water from the bilge. Then I worked carefully back from the bow, searching for pooling, and found seawater in the forward bilge.

This had accumulated in 2020 when the head's pump had refused to flush seawater into the toilet bowl.

The problem had been traced to the corrugated PVC multiflex hose, which had been leaking from the seacock.

This was solved by cutting away the hardened area of the hose and refitting the hose clips, tightening them to make a waterproof seal around the seacock.

After this discovery, I then proceeded to check and remove all traces of water from under all the floor areas back to the main bilge.

I felt confident at the time that I’d solved the problem. I was wrong.

The water appeared once again so I mopped it out then patiently waited until we had another monsoon before having another look in the bilge – which was bone dry.

To borrow the catchphrase of a well known TV character: ‘I don't believe it!’ Back to engaging the brain.

So, the next potential cause of the water getting into the bilge must be via the deck fittings when I washed the boat.

To check, I dried out the bilge but it was another ‘I don't believe it!’ moment.

The culprit turned out to be the brass fitting on the end of the fridge defroster hose. Credit: Alan England

Despite no washing, bilge water had reappeared. The engaged brain was getting worn out with all these exertions.

The other potential cause of water in the bilge was from the fresh water tanks.

So all the hoses and connections were checked and the tanks filled to overflowing.

The solution was to fit a non-return valve that allowed the fridge's defrosting pump to work more efficiently. Credit: Alan England

After the fresh water system had been thoroughly used for a few days the bilge was checked again. ‘I don't believe it!’

The bilge was bone dry. Closer investigation showed the water seemed to be coming down the port side of the bilge's moulded GRP wall via a small hole in the moulding.

Using a syringe, I then attempted to remove all the water from the recess and then laid paper towels around the area to confirm that I’d succeeded in fixing my leak.

Had I finally found the Holy Grail?

A few weeks later I checked the bilge again, but discovered the paper towels had become saturated with water, confirming another failure in detection.

As the water in the bilge never exceeded two litres and could be removed with a sponge, I learned to live with this relatively minor inconvenience.

The months passed and I got into the routine of periodically checking the main bilge.

Older style ribbed hose

However, water would occasionally appear there as if by magic. This needed sponging out, which was annoying but not life-threatening and not one of the worst problems of life on a boat.

As I grew older (but no wiser) the mystery continued to confound me.

As Sherlock was not available to solve the mystery, I hoped that my two bilge alarms would give sufficient warning should the problem become more serious.

Internally reinforced hose

Soon we were into the summer heatwaves of 2021 with the temperature in Malta starting to rise above 40°C. This created a serious emergency, namely the problem of how to keep the beer cold.

In these temperatures my old fridge – like its owner – was struggling to cope.

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Fortunately I was able to keep the fridge at an average internal temperature of 10°C by running it off the 220V mains electricity supply.

The holding plate had built up a large amount of ice around it, thus keeping the beer very cold.

This is the purpose of a fridge, of course, and enabled civilised life to be sustained, but it also revealed a clue as to why I was getting water in my bilge.

As the large build-up of ice was also affecting the fridge's efficiency, once again Sherlock was called in to solve the case.

Investigation revealed that the holding plate had iced up to an unacceptable level.

The defunct oven had been replaced with a microwave, and it was under this worktop area that the problem occurred and had to be accessed with contortionism – not much fun in Maltese summer cabin temperatures of up to 35°C. Credit: Alan England

Unfortunately after defrosting the fridge I encountered another problem, the fridge defrosting pump failed to pump out the defrosted water.

Solving this problem was not an enviable task. I’d previously replaced the defunct oven with a microwave, but to find out why the pump was failing I had to work in the confined space underneath it – a job for a contortionist.

The cabin temperature was 35°C, but the pump had to be checked, which meant disconnecting it at the sink. It was then immersed in water and operated successfully, confirming it was serviceable.

The pump was reconnected and the search continued. The defrosting hose was then traced to the culprit – a brass hose reducer connector.

Progress at last. However, further work was still required, which involved disconnecting the 20mm braided reinforced hose from the offending connector.

The end of this hose was then inserted into some water and the pump successfully pumped it into the sink.

Further investigation revealed that the hose clips around the corrugated PVC Multiflex 25mm hose were found to be tight.

However, it appeared that water had leaked from the end of the hose, which had hardened with age.

Solving the problem was relatively easy!

The task required continuing working in a confined space in a cabin temperature still at 35°C and suffering loss of skin from my knuckles in order to fit a one way hose connector non-return valve (NRV) – which should have been fitted originally – and then to tighten the hose clips.

The conclusion, after suffering considerable frustration and sweating about a kilo loss in weight, is that perseverance pays off and nothing beats the satisfaction of a job well done.

Part of the problem had been caused by the plastic hose hardening at the terminus and causing a leak.

I’m in the process of switching the bilge hoses from corrugated (or ribbed) hose to reinforced hose.

Tips from PBO's Jake Kavanagh

"For me, the bilge for me is an area which all good sailors should treat in the way that ‘Cleanliness is next to Godliness,’" says Alan England.

"The bilge should always be kept clean and dry, for many boat problems originate there or give clues to problems elsewhere, as I was to discover."

Plastic covers on the sharp tails of hose clips

A tour of any modern boatbuilder shows that they wholeheartedly agree.

Here are some examples of good practice to avoid bilge-area problems, partly by making solid and dependable connections, but also by the fast identification of any pipes or outlets, especially important if there is a sudden leak at night or in a seaway.

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