How we installed a new engine on our yacht

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Yesterday 05:00

When a mysterious loss of coolant jeopardised his sailing, Andy Du Port knew the time had come to replace his yacht’s veteran Volvo Penta

Auxiliary engines, as they were called in the old days, were hot, noisy, smelly lumps of metal that weren’t usually powerful enough to motor into wind or tide. My first yacht, which I bought in 1979, had a single-cylinder Stuart Turner petrol engine. It had about three moving parts, tended to misbehave on the starboard tack, but reacted remarkably well to a shouted command to buck up when its sense of duty was wanting.

That engine’s power output was less than the average lawn mower and if full astern was engaged 20 yards before her berth (metres had not been invented back then), there was a fighting chance the boat would stop before causing too much damage. On the upside, it was easy to maintain and could be removed from the boat and taken home in the boot of the car.

My second boat, an elderly 28ft Twister, had an unreliable two-cylinder petrol engine which I soon replaced with a brand new Bukh 10 diesel, doubling the horsepower at a stroke. Basic maintenance was still within my capabilities – a set of spanners and a hammer solving most problems.

Then engines became more sophisticated and the cost of spare parts rocketed. We had another two boats, each with slightly more powerful ‘donks’, before we bought Kudu, a Hallberg-Rassy 34, in 2005. Her original 1998
29hp Volvo Penta MD2030B was archaic by today’s standards but, apart from changing the oil, filters, impellers and the occasional worn out rubber hose, there wasn’t much that could be done before professional help was needed. And so, towards the end of the 2021 sailing season, the saga began…

Kudu’s original 1998 Volvo Penta MD2030B diesel engine showing signs of age

Coolant loss

The first sign of trouble was a slight loss of coolant. Although I had changed it at regular intervals, I’d never had to top it up from one season to the next. Now the level was dropping to the salt water tube in the heat exchanger every three to five hours.

I was advised to carefully check all the hoses on the fresh water pump. Having removed one, I found the brass tails were almost completely corroded away, necessitating a replacement pump. However, my hope that all was now fixed was unfounded, and coolant was still disappearing.

We then set about checking the entire coolant system, and replaced several components including the end caps on the heat exchanger, and then the thermostat. Coolant loss seemed to be reduced, but it still needed topping up, and I wasn’t confident we could motor for more than six hours before it needed attention. You can’t safely top up a hot engine, so long passages – such as crossing the Channel on a windless day – were not practicable.

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Grey smoke

The next snag was difficulty starting.

The battery was fine and the starter motor turned over the engine as normal, but it needed more cranking than usual and ran very unevenly while emitting grey smoke for several seconds before settling down. After consulting my engineer, Steve, one of the glow plugs was deemed to be faulty and needed to be changed. Not normally a big job, but it was seized solid in the block and couldn’t be removed before it sheared off.

Luckily, what was left didn’t affect the engine running and, having had the remaining two glow plugs tested, we decided to wait until the cylinder head could be removed and the remains of the duff glow plug drilled out. All was well when the engine was run briefly during the winter lay-up, and once again we were confident the problem had been solved.

The old engine’s cylinder head removed

Stay or go?

With the boat afloat again, we gave the engine several good runs. Starting was easier but not without a fair bit of coughing and more than the usual puff of grey smoke. For some reason starting was more difficult when the engine was hot. In the meantime, we continued sailing while Steve scratched his head.

He recommended that the injectors and injector fuel pump should be checked by a diesel specialist.

Waiting for this work to be carried out delayed the start of our summer cruise. However, everything was reassembled by the second week of June and we had to make the decision whether to go ahead with our original plan of sailing to the Netherlands.

The engine was certainly starting more easily when cold but loss of coolant was still a worry, particularly as we would be committed to several long passages and potentially a lot of motoring in the Dutch inland waterways. We decided to go.

The new Beta 25 engine, still in its box, weighing in at 260lbs (118kg)

Cross channel

By the time we had sailed from Gosport to Eastbourne and then on to Calais, the rest of the trip was looking feasible. Soon after arriving in Nieuwpoort from Calais we had to move berth. The engine was still at normal operating temperature and was very reluctant to start. This gave us second thoughts about continuing east. Gales delayed us further, and it became clear our time was running out. So, reluctantly, we made our way home.

Back in Gosport the engine still wasn’t right. Steve thought there might have been a leak of coolant into the oil sump. It was possible, he said, that the engine had overheated at some time and the cylinder head had become slightly warped.

After a few more running hours it was apparent coolant was still disappearing, and the engine was still reluctant to start when hot. A decision had to be made – continue throwing money at the problem or take the plunge and get a new engine? We settled on a new engine.

A marine electrical engineer installed a voltage-sensitive relay

Conversion kit

A like-for-like new Volvo Penta engine wouldn’t have been compatible with Kudu’s existing Volvo Penta saildrive, so the search was on for a different make which would match the saildrive and fit the available space. We considered a refurbished engine but were strongly advised against it if we wanted to be confident of having a reliable engine that would last more than a few years.

At this point I was alerted by a friend to a link to Beta Marine. The link showed that Beta produces conversion kits which enable its engines to connect to Volvo Penta saildrives. They also offer bespoke mounting feet which can be made to fit existing engine bearers. After a bit more research, and having spoken with several Beta owners, I placed an order for a Beta 30.

Once the new Beta 25 was lined up with the saildrive, the rest of the installation was straightforward

Out with the old

Before the feet could be made, Beta needed exact measurements from the face of the saildrive to the existing holes in the bearers. We soon realised there was no way we could measure accurately enough for the new mounts to line up precisely with the old holes. While we were measuring, it also became clear that the Beta 30 would be a very tight fit and could require unsightly and impractical modifications to the companionway steps. To be safe, I changed my order to the slightly smaller Beta 25.

When the new engine arrived Kudu was lifted out in preparation for the swap. Within a week, Steve had removed the old engine and hoisted the new one on board. From then on the installation was quite straightforward:

The new engine was lined up with the saildrive, then briefly moved again for the holes to be drilled in the bearers.
New hoses were bought for the calorifier.
A Vetus air vent (anti-syphon for the salt water system) was fitted.
The bulky old Volvo Penta silencer was replaced with a much neater Vetus silencer/waterlock.

Andy kept the original three-bladed folding propeller which was matched to the old Volvo Penta MD2030

Timed runs

While Steve was working below, I fitted the new control panel in the cockpit. Although it is exactly the same size, the Volvo Penta panel was offset in the recess to allow for the ‘Stop’ lever (the Beta has a much tidier push button), so I took the opportunity to line everything up.

A bit of sawing, drilling and a plastic chopping board completed the job. When it came to connecting the wiring loom to the engine, we found it wasn’t quite long enough, so an extension was rapidly ordered from Beta Marine. Eventually, all was done and we ran the engine for the first time, with a hose feeding the saltwater cooling system. After launching, the engine started as soon as I turned the key. We were underway again at last.

After 15 minutes alongside at one-third throttle, we cast off and went through a routine of timed runs at various throttle settings. It managed to get up to 3,300rpm without smoke, and Beta confirmed that this was fine, as long as I ‘kept an eye on the temperature alarm if operating at full power.’ It seems to be very happy at cruising revs of 2,250-2,500rpm, giving a speed through the water of between 6 and 6.5 knots.

It cost Andy just under £8,000 to complete the re-engining of his Hallberg-Rassy 34

Alternator charging

One anomaly between Volvo Penta and Beta is the wiring for charging the batteries from the alternator. Volvo Penta engines charge the domestic and engine batteries via a split charge diode, but Beta engines just charge the engine starting battery.

In order to charge the domestic batteries with this arrangement you need to connect all the batteries together when the engine is running, then remember to separate them again to avoid inadvertently draining the engine starting battery when sailing. The solution turned out to be quite simple. A local marine electrical engineer installed a voltage- sensitive relay – a two-inch cube which sits alongside the battery box and apparently requires no further attention.

Costs incurred

The total cost of the project (new engine, replacement parts and installation) was just under £8,000, but I clawed back around £1,000 by selling the old engine and various redundant Volvo Penta parts, including a brand new exhaust elbow. Further savings will be made in the long term, given the much cheaper Beta filters, impellers and other ‘consumables’.

With any luck, after many months of frustration, Kudu now has a dependable engine which should last her for many years to come.

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