Aiming to do our bit for the environment, we recently made a number of lifestyle changes – and one of them was converting our Parker Super Seal yacht into an electric sailboat with the use of an ePropulsion electric motor.

It has proved a great transition in so many ways, taking our sailing experience to the next level. At first it felt a scary, big step into the unknown, but in fact proved a relatively straightforward job.

Skylark is our eco Parker Super Seal. She is an accomplished sailing boat, quick, safe, and fun. She is a joy to sail, we regularly achieve over eight knots through the water.

Our cruising range is generally the South Coast between the Solent and the West Country plus the Channel Islands and France. We have aspirations to take her round Britain, we just need to prioritise the time.

Skylark is primarily powered by sail, a main and genoa (140%) and a couple of asymmetric spinnakers.

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Leap of faith

Last winter we took the big decision to convert Skylark from diesel to electric propulsion. So her motor is now a 6kW electric engine, with a 9kWh lithium battery, both made by ePropulsion. Leisure power is supplied by Totalcool 12V lithium batteries and solar panels.

Was it a crazy or brave step? Well, somehow taking a perfectly serviceable engine out and going to an emerging technology seemed quite scary, especially when it involved drilling holes through the bottom of your own boat.

Interestingly, having done it, we now feel the most complex part was taking the old diesel out and that if you can put together a piece of IKEA furniture you can convert a yacht to electric. We will never look back, nor go back to a diesel.

Out with the old

Skylark’s 40-year-old Bukh 10 engine was still going strong, well bedded-in but was getting expensive to run and maintain. And like all diesels it was not exactly environmentally friendly.

Taking it out wasn’t something to be rushed. Getting the spanners into what is inevitably a very restricted space is an art that takes a while to master.

Persuading the embedded bolts and fixings to loosen is not for the faint hearted. However, a little cussing, the odd cut and much WD40 given time to work seemed to do the job.

In a few hours each day over a couple of days we removed the Bukh. The bits we were worried about, the engine mounts and the drive shaft, turned out to be easier than expected.

The numerous hoses and cables felt a bit ‘Forth Road Bridge’ and seemingly endless, although it was a relatively straightforward task. Just painstaking and on occasions painful.

Having taken everything off the engine the next task was to lift it out. At 140kg this was not a light load. We constructed a frame over the boat using scaffold poles, attached a chain hoist and lifted it gently up and out. It was a dream, all went without a hitch.

Once in the air we had the advantage of having the boat on her trailer, so simply rolled the trailer forward and lowered the engine onto a wheeled pallet. Job done.

With the engine out, there was so much space which got even bigger as we took out the exhaust system. This was actually a genuine ‘five minute job’ and revealed a massive space now used for extra stowage.

Then out came the fuel tank and its attendant tubes and more space gained. But most of all was the joy of saying goodbye to smelly diesel.

Next was to fill the redundant holes in the skin of our ship, the water inlet and outlet, the exhaust outlet. That felt good, the fewer holes in the hull the better!

Finally, the ‘Big Clean’! The bilges of any boat are always a bit grimy, but years of oil and muck warranted a really good scrub. Traffic film cleaner worked well as a degreaser, then loads of soap and water – a task made so much easier knowing that it was the last time our lovely hull would be subjected to those yesteryear hydrocarbons. Hurrah!

Finally we had a clean slate and perfect foundations for the new installation.

In with the new

This proved to be so straightforward, despite being a little daunting at first. Just like IKEA kits, with a good read of the instructions and marshalling the right tools we set to with an engineering chum (to bolster our confidence!)

First, we spent a good amount of time planning. Second, we glassed a 50cm x 50cm marine ply pad onto the inside of the hull, as belt and braces to spread the load of the engine fitting. Essential, no. Diligent, yes. We felt it ensures our engine will be safe and securely mounted for the coming decades.

The ePropulsion Pod engine is totally external and is simply secured to the hull with three 10mm bolts. All that’s required is a 66mm hole for the cables to feed through.

Carefully working out how and where to position the engine took a good amount of time. We cut off the last 15cm of the drive shaft cowling, otherwise our propeller would have been too close to the rudder. The cutting was easy (in retrospect). Shaping the spacer to the shape of the hull so the engine would sit vertically did take time.

In retrospect, a sharper cutting edge, and more confidence, would make it much simpler next time. Engine fitted, next we moved on board to install the controller, the charger, the morse and the control panel, all very straightforward.

Our top tip – place the control panel in an easy to see position with the instrument cluster on the forward cockpit. The data is really useful and benefits from easy viewing while at sea.

Next came the battery. Our ePropulsion E175 9kWH battery is compact at 52 x 55 x 27cm although quite heavy at 87kg. It fits perfectly on the engine mounts, the load spread by a piece of marine ply, and takes up only half the space of the old engine.

We lifted it on board using the same chain hoist, lowered it gently into the cabin and slid it forward on an old mountain skateboard that I found in the garage. It was so much simpler than we had dared hope.

Finally, connecting it all up was a steady, logical process that needs to be approached methodically, but it’s not difficult. Then, the big switch on. A press of a button and all springs to life.

I still marvel every time I switch it on. Apart from a few lights, there’s little to show or hear! Push the morse forward and silent, powerful thrust results.

Subsequently, we haven’t looked back and will certainly never go back to burning noisy, smelly, dirty, hydrocarbons with all the damage that they do to our fragile environment.

12V leisure system

Prior to conversion Skylark carried two 12V batteries. These worked well for day sailing, charged by the engine when motoring and trickle charge solar when at rest.

However, with an electric engine there is no alternator so power can get a bit short living aboard after a couple of days out, running instruments, charging phones, lighting etc, without a means of recharging power.

A new solution was required and after much experimentation we have gone for two Totalpower 500 12V lithium leisure batteries, one for the instruments and one for the Totalfreeze fridge. This provides so much power and is easily maintained by the Totalsolar 100 solar panel.

Lithium batteries have many advantages. You can use all the capacity, as opposed to around 50% with lead acid and they can run 240V appliances as well as 12V. In-battery data screens provide all information live.

Weighing only a few kg – less than a quarter of the weight of lead acid batteries – they are much easier to use and so much more versatile.

Wind generation

Currently, we carry an experimental 48V wind generator. So far it is proving most successful. It is powerful, quiet, and neatly out of the way.

The great benefit is that on a swinging mooring, or at anchor, it means we rarely need to use 240V. We are continuing our research into which brands to select until we have enough data to make informed decisions.

Solar generation

We carry two 12V Totalsolar 100W solar panels This means that we charge the fridge battery in parallel with the leisure batteries. We now have much more 12V capacity than we need – and there is now always ice on tap!

Tenders and paddleboards

To complete our eco set-up our tender has an ePropulsion electric outboard recharged by hydrogeneration and solar. We carry a lightweight ThrustMe engine for runs ashore. Even our Sandbanks Style paddleboards have an electric Vaquita motor, enabling us to always get back to the boat against strong winds and tides.

Electric sailboat experience

Some people fear running out of power, but it’s not proving an issue for us. Electricity is generated by the engine hydrogeneration system when sailing. Input is around 100W per knot when sailing between 4 and 10 knots, at the cost of 0.7 knots of boat speed. In addition, we have the wind generator and on occasion 240V mains power.

Solar panels charge the 12V system when living aboard. Skylark lives on a swinging mooring and on the odd occasion when we want to charge from the mains, usually before a long passage, Chichester Harbour Master and MDL Marinas supply 240V electricity free of charge to electric boats at four points around the Harbour (an eco practice worth encouraging).

In reality we rarely use more than a small proportion of the engine’s potential. Skylark weighs approximately three tonnes loaded. We normally cruise at about 975W at just under four knots, which gives over nine hours of motoring.

A full 6kW gives around eight knots for a much shorter time. We lived aboard for three weeks in the summer, charged just three times (as there was very little wind), and never went below 50% on the battery.

Motor sailing back 29 miles from Southampton Town Quay in under 4 knots of wind, with strong tides both with and against us, we used less than half the battery.

Electric sailboat conversion costs

At the time of conversion we’d retired from the commercial world and had been philanthropists for eight years, gifting our time, so cost management was a critical factor. We spent a good deal of time looking at costs, and the conversion has dramatically reduced our running costs. The logic is as follows:

Bukh annual running costs

I’m a reasonably capable with practical maintenance, however the single cylinder Bukh with its quirky oil seals and gaskets, took me days of work, so it was more practical to work with a professional engineer at a cost of around £300pa for parts and labour, fuel was around £100pa, my morse replacement in its last year was £268, and a new 12V engine starter battery at £120 making a total of £788 spent in 2020.

Electric sailboat running costs

The total cost of the engine set up, including engine battery controller etc. was £6,800. The chain hoist cost £35, 66mm drill bit £12, fuel £0 (free electricity supplies in Chichester Harbour) so total installation cost £6,847. This engine should last for decades.

Assuming a conservative write-down over 15 years, this equates to £456pa. Economically, going electric has been a great decision. It costs around half the annual cost of before, and is so much less damaging to the planet.

Electric sailboat liveaboards

Our three weeks away were an absolute joy – silent eco sailing and silent motor-sailing in the many days of calm we experienced this summer. Everyone stops us wanting to know how we do it, as we silently cruise past 38-footers!

Range anxiety? We are totally over it! We did passages of up to 40 miles in little wind and didn’t use more than 50% of our battery capacity.

We motored from the Solent into Poole Harbour where we spent several days pottering and stand-up paddleboarding, only charging from shore power prior to embarking on our next long passage as due diligence, since the calm weather had limited our wind generation.

We have found that, as with all electric engines, there is a huge amount of torque giving fabulous manoeuvrability and the joy of silent motoring.

At steady speeds she uses very little power, then faster speeds seem to push the effort up on a roughly cube basis. This is great at encouraging us all to be traditional and work with the wind and tides not despite them.

Having an electric engine also totally changes the way one sails, tacking up wind with just 2-300W gives an extra couple of knots and an additional 10° of pointing angle (as the apparent wind shifts), and all this silently. Wow!

Electric sailboat conversion: What we learned

Switching to lithium

We haven’t found anything to fear and it takes our sailing to the next level. The one thing that took us a while to suss out was how to run our leisure systems as lead acid batteries only last a couple of days with no alternator on hand!

Our learning was to ditch lead acid in favour of lithium, a quarter of the weight and you can use all the battery power, not just 50% of it. We now have so much power that we happily run a TotalCool fridge solar charged.

The future

We will never go back to hydrocarbons. Going electric is such an all-round better experience as well as making a significant difference to the fragile marine environment. Downsides? The only one we’ve found is that folk joke they’re reluctant to race us, as they can’t tell if we’re running the engine!

Looking to switch to an electric outboard engine? Click here for advice on how to choose the right engine for your type of cruising

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This feature appeared in the April 2022 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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