Solar arch

We have been trying to work out a design for a solar arch for a very very long time. Designs have come and gone multiple times. When I wrote our Solar Plan back in September, I said “I havenโ€™t quite given up on putting panels off the back of the boat” but at that point we hadn’t make the decision to go for an electric motor and we hadn’t connected the dots with self steering.

So we continued to think about what we can build. This video from Sailing Britaly has continued to be particularly helpful.

But a solar arch on Vida is very complicated ๐Ÿ™‚

We have three things that together make it very complicated.

  1. As a typical cruising boat design from the 1970’s our Rival 38 has a relatively narrow stern. That obviously restricts the space available for solar panels compared to a modern design where the beam at the stern could easily be doubled on another 38 foot design.
  2. Then we make it worse by having a ketch rig. Not just a ketch rig but one with a mizzen boom that stretches past the pushpit rail to end level with the very end of the stern. So we need to position the panels to avoid the boom, it’s sheets etc.
  3. Finally the extra thing that makes it difficult is something we don’t yet have. A Hydrovane Self Steering system (I mentioned that this might be needed in Zero fossil fuel sailing). We need vane steering to reduce electric consumption to a manageable level (electric autopilots use a ton of power, I’m guessing a 42 year old even more than a new one). With a centre cockpit and the wheel in a wheelhouse any vane steering that connects to the steering wheel via rope is a non starter. We don’t have space under the aft cabin bunk for a Cape Horn system that connects through the stern directly to the top of the rudder stock. The Hydrovane has the additional advantage of giving us a spare rudder.

So the plan is to shorten the boom a little (120mm). That should work without re-cutting the existing sails. When we replace them we will have a fully battened mizzen with a fat head and a shorter foot so the boom can be shortened a little more (as well as the sail being more efficient).

We have sent the details off to Hydrovane for a quote. We think the unit can be mounted high enough for the van to be above the boom and not hit the sail. The only time it might touch is in very strong winds (when the vane leans over more), but by then the mizzen would be reefed or lowered out of the way.

So now we have been planning the final piece of the puzzle. The solar arch.

We are going to have 3x Victron 175 watt panels high above the stern. That means a rectangle approx 2m wide and 1.5m long. Unfortunately even above the complications that I have already listed we have added 3 more.

  1. As solar generation is so important to us we need to be able to tilt the panels towards the sun to increase their efficiency.
  2. We need to be able to move them forward and aft. In a marina as well as in a storm we do not want solar panels sticking out 1.5m beyond the stern of the boat. So we need a “parked” position where they do not extend beyond the stern but instead extend over the mizzen boom (obviously in this parked position we can’t use the mizzen, a restriction we are happy to accept).
  3. Our budget is limited, we can’t afford to pay a professional to custom build something beautiful in stainless steel. Due to the height and restrictions that reduce the opportunities for cross bracing we don’t think that bolt together fittings (such as used by Sailing Britaly) are going to work. We can only find the range of joint connectors we need, for 25mm tubes which we don’t think is going to be strong enough.

We will document our design as we build it (and I really want to get the mizzen mast up and the hydrvane fitted first to check clearances as we go). However, this is the basic idea.

Two carbon fibre “masts”. The bottoms will be halfway down the stern, one each side. They will be vertical fore and aft (positioned so that the shortened mizzen boom just misses them) and they will slope outwards as they go up. So approx 1m apart at the bottom and just over 2m apart at the top.

There will be a pair of cross braces as an X to hold them vertical side to side. Also each of them will have a pole from just under the boom going forward to the size deck to keep them upright fore/aft.

The 3 panels will be in a tray that fits between the mast tops. We have figured a way for the tray to move to the forward or aft position and also for the whole tray to tilt to face the stern or to face the bow.

Fortunately, we think it is going to be a lot harder to explain than it is to build ๐Ÿ™‚

While the carbon fibre poles are quite expensive (over ยฃ700) everything else is going to be pretty cheap, so hoping to keep the total cost under ยฃ1,100. That for something that should be very strong, pretty light and give us really good functionality.

Sustainable Sailing and Human Power

I’ve been quiet on here during the COVID-19 pandemic so far. More urgent priorities and has seemed inappropriate when so many have been dying, ill or struggling in other ways. However, some countries are now starting to move beyond lockdowns and it now seems more appropriate to focus on building a better future. One that is more human in scale, more caring of people and planet, more sustainable. So here are some thoughts of another aspect of bringing Humans into Sustainable Sailing

With a goal of zero fossil fuels being central to our understanding of Sustainable Sailing there is a big gap in what we have been planning so far.

What about using human power?

I’ve come up with a number of potential uses for human power when Sustainable Sailing. Let’s see if any make sense.

  1. Moving the boat
  2. Replacing electric powered items on the boat
  3. Generating electricity
  4. Getting to/from shore
  5. Getting around on shore

Now we have a list, time to consider them in some detail.

Moving the boat

The best examples I know of for actually moving a yacht by human power come from two races. In the UK The Three Peaks Yacht Race (run to and climb the highest peaks in Wales, England and Scotland; sail between them; engines only allowed within specified areas of the ports) and the Race to Alaska (No motor, no support, all the way to Alaska.
The physical endurance, saltwater know-how, and bulldog tenacity to navigate the 750 cold water miles from Port Townsend, Washington, to Ketchikan, Alaska). There are great videos from Race to Alaska 2019

My conclusion is that if you want to be able to make any real progress with human power to move a yacht then 3 conditions need to be met

  1. You need a large crew so that you can have people who are rested enough to cope with a storm that follows a long calm where you have been using human power.
  2. The lighter and easier the boat to move the more practical it is. A racing multi-hull is the best option, a live-aboard heavy displacement mono-hull very bad.
  3. So far the most effective solutions for speed are also fragile and take up a lot of space. Neither good for long term cruising.

Therefore, it seems to me that it is better to invest in improved sailing performance in light winds to minimise the amount of time that human power could improve your speed. For shorthanded cruising (eg a couple living aboard) an electric motor is going to be far less risky in harbour situations where you don’t have spare crew or where you need to be able to cope with tides and headwinds while manoeuvring.

Replacing electric powered items on the boat

Probably the only electric powered item that we plan to have that we could easily (and more cheaply) replace with a human powered version, is the windlass for raising and lowering the anchor.

The electric windlass we are fitting can be used manually. However, having an electric windlass seems to us to be a great safety feature.

It allows us to have a much heavier anchor and chain,

it means we won’t put off moving to a more sheltered anchorage because we don’t want to manually raise the anchor,

if you need to leave an anchorage in bad conditions we won’t start sailing while physically exhausted from raising the anchor.

It raises the anchor much faster, which with the saving in physical effort makes sailing on and off anchor much easier

So we think investing in better electrical capacity is a better option here.

More and more yachts, particularly larger ones now have electric winches and/or electric sail furling. We plan to stick to manual as long as we are physically capable, possibly getting an electric powered winch handle rather than a whole winch when we need help.

Most of our other electrical systems are cooking or water related. So far no obvious human powered options (water-making would be great but falls far short of daily needs for a lot of effort).

Generating electricity

How about using a bike or something to generate electricity while we exercise? Our conclusion is that it can’t generate enough to be worthwhile (especially when you factor in a small crew). Time and money better spent ensuring maximum power from your solar by keeping it clean, shadow free and pointing at the sun.

Getting to/from shore

This is where I believe it starts to get very interesting.

We have gone for probably the most popular dinghy style (A rigid inflatable with aluminium hulls). Having inflatable hulls makes getting on and off the boat so much easier and safer with no risk of damage. An aluminium hull is both lighter than the traditional grp and much tougher for dragging up beaches (it is also fully recyclable). Ours is a Highfield Classic 290 which we should be able to store on our fore deck when sailing (just in front of the main mast), it also fits inside our van for transport to and from home (nowhere to keep it near the launching place near our mooring).

Ribs are pretty rubbish to row (the hull is too wide with too much water and wind drag, plus the seating position is inefficient. So we have an electric motor, but that means we sacrifice speed, it won’t be possible to plane (but we don’t expect to want to zoom to fantastic diving spots for example).

Could human power provide an alternative? We have looked at various “toys” to use when at anchor. SUP’s (stand-up paddle boards) are very popular and the inflatable ones easy to store. But practical and useful they are not, unless it is warm enough to wear just a swimming costume and you don’t need to go far and it is smooth water without much wind and you don’t want to carry anything. An inflatable kayak is a little better in practicality.

So instead we are wondering about carrying something designed to row well. The best option that we have found is from Angus Rowboats, they have an amazing track record (first human powered circumnavigation, rowing across the Atlantic, coming first in the under 20 feet category of the Race to Alaska). They have this beautiful Oxford Wherry available as plans or a kit. I’ve had a chat with Colin Angus and we agree it should be possible to make a minor adjustment so that the wherry can be divided into 3 nesting parts for storage on deck (we think it would fit on our aft cabin). We think that this would be the most efficient human powered dinghy that you could carry on a yacht. With a sliding seat you will be able to carry yourself and a passenger to explore rivers and harbours at a similar speed to our outboard engine on the rib.

We don’t think this would be suitable for our only tender, the key issues is that with the sliding seat you have to have outriggers for the oars and this makes coming alongside a yacht very difficult without causing damage (so instead we will use the rib as a dock/boarding platform). The lack of an engine option makes carrying large amounts of shopping or fighting the fast tide in the Menai Strait unattractive.

Getting around on shore

It amazes us how few of the sailing YouTube channels carry bikes with them to get around on the shore, particularly to go shopping. In a recent video Beau and Brandy had a 30 minute walk to the supermarket. They then had to push the loaded trolley back before an hours round trip returning the trolley.

Matt and Amy on Sailing Florence seem to be the best sorted with two Brompton bikes but we think they too are missing a key thing to transform using bikes for shopping. What they need is a trailer. For us there are two stand-out options (they need to fold and they need to be suitable for any bike and they need to resist corrosion). If we didn’t already have a trailer then the Cyclone Range from Radical Design are brilliant. The other option (and yes we have one) is from Carry Freedom We have an old Large Y-Frame but there are other options now. Here is mine in use (Cargobike sadly not so suitable for fitting on board boats, plastic box is just bolted on, anything else could be used). It works as a hand cart too for getting right to the loading point.


By far the most cost effective and transformative use of human power in Sustainable Sailing is a bike with a trailer.

A good rowing dinghy (probably in addition to a RIB) comes second.

For everything else your energy is better used improving your boats sailing ability and electrical generation and storage.

Reduction gears for yacht Electric Motor

So we have the main components for the reduction gears for our electric motor. Note that in the picture the items are laid out on their side, in reality the electric motor will be above the reduction box shaft.

On the left is a sheet of paper representing the electric motor (An HPEVS AC-34 ) out of the top comes it’s 1.1/8″ drive shaft.

Connected to the motor drive shaft is a 2012-1.1/8 Taper Bush (Dunlop) which is used to attach a 56-8M-30 Taperlock Timing Pulley The Taper bush has key (a length of square section metal that connects slots in the motor drive shaft and in the taper bush to keep them locked together when the motor spins).

This 56 tooth pulley is connected to a 80 tooth pulley by a 30mm wide timing belt with 8mm pitch teeth.

The ratio from the 56 tooth to the 80 tooth pulleys is chosen so that the motor can be set to spin the propeller at it’s designed maximum of 1400 rpm.

The 80-8M-30 Taperlock Timing Pulley is connected to a 1.1/4″ stainless sheet reduction box shaft via a 2517-1.1/4 Taper Bush (Dunlop) which again will be prevented from rotating with a key connected a slot (to be cut) in the shaft to the slot in the Taper Bush.

On the reduction box shaft there are two stainless steel thrust bearings. One of these will be bolted to each end of the motor frame. They will be facing in opposite directions to absorb the thrust from the propeller in both forward and reverse directions.

The ends of the motor frame are each made of 2 sheets of 3mm stainless steel sheet. These sheet frame ends will be bolted directly to the two ends of the motor and to these bearings. We have lengths of stainless steel right angle and flat bar to hold this frame together rigidly and attach it to the engine mounts (one we buy them). The motor will be bolted to slots in the frame so that the belt tension can be adjusted by raising or lowering the motor in the frame.

At the bottom of the picture we will connect the reduction box shaft to the existing 1.1/4″ propeller shaft. A Clamp on Coupling on the reduction box shaft will be bolted to flexible coupling on the propeller shaft. This means we don’t need to achieve perfect alignment of the reduction gear shaft and the propeller shaft. It also helps reduce vibration as the motor can be attached to more flexible mountings.

To keep the electric motor in as dry and salt free environment as possible the original stuffing box (that creates a waterproof seal around the propeller shaft as it exits the boat) will be replaced by a modern dripless model. While very reliable the original stuff box isn’t maintenance free and always drips a little salt water into the boat. We are looking at the Manecraft Deep Sea Seal at the moment (we are trying to avoid products that require a pressured water supply to the seal as we won’t have engine cooling water to connect to it). These dripless seals also cope better with vibration and movement in the shaft without causing wear in the bearings.

As the propeller shaft goes out of the boat in runs in a cutlass bearing. These wear out and ours needs replacing. Until we can get the existing one out I’m not sure of the dimensions we need.

The propeller needs a clean but otherwise is in good condition so we won’t be replacing it. The three bladed design creates more drag when sailing than either two bladed or folding designs. However, it is more efficient when using the motor and should also be better at regen (charging the batteries by turning when sailing and using the electric motor as a generator).

Once the motor arrives with it’s controller we can get the details of the frame sorted and start on all the connections to power and control the motor.

The biggest Electric Motor difference compared to Diesel

The biggest difference is availability.

With an electric motor instead of a diesel in your boat you can achieve the same/similar performance in power/speed. At the same time you can get better reliability and lower maintenance.

However, the biggest difference is that you have to manage availability.

With a diesel availability is taken for granted. We assume that if you have fuel the engine is available:

  • whenever you want it
  • however long you want it
  • at whatever speed you want it

these are not the same with an electric motor as everyone of them depends on your management, preparation and planning around availability of the battery bank.

Note that here I’m talking about electric motors that use battery banks that are charged primarily from renewable energy. If you have a generator (usually diesel in this case) that can generate the same power as the motor uses then you are in the same situation as with a diesel engine.

What affects availability?

There are three key variables that affect how much electric motor availability you have at any particular time. All these need to be managed and none of them can be changed instantly at the point of need.

Hence, using an electric motor requires a mindset, especially changes in how you manage the boat and the plans you make.

The three variables are:

  • Technical specifications (particularly of battery bank and renewable energy generation)
  • What you have been doing up to this point (ie what state is your battery bank in at this moment)
  • What you are planning to do (and what contingency plans you have made)

What makes things easier?

Spending more on the technical specification increases your capacity and reduces the amount of management and planning you need to do. For example a bigger battery bank or a larger solar panel array both mean you will have more capacity available and so less need to manage the capacity and the plans become easier to make.

Choosing a catamaran makes things easier as there is always going to be more space for solar panels.

Cruising less often or less intensively makes things easier as you have longer between passages to charge your batteries.

Cruising is warmer climates makes things easier as there will be more sun to get more power out of your solar panels (at the extreme, solar panels are going to be of zero use in a polar winter with 24 hours of darkness).

Longer passages (as long as there isn’t a tight schedule) makes things easier as you can sail for days while charging the battery bank ready for the next landfall.

Better sailing performance with special focus on light winds and going to windward (when people are most likely to motor or motor-sail)

What makes things more difficult

Tight and fixed deadlines.

Wanting hands off systems where you pay someone to do the maintenance and then have instant and complete availability 24/7.

Always available “luxury” (air conditioning, hot water, heating, large freezers and fridges, electric autopilot, electric winches)

Complicated coastal waters (tidal inlets, long and narrow harbour entrances, big marinas, headlands with big tidal streams, lots of traffic)

Managing availability

Diesel inboard engines have managed to create a reputation of always being available and for most weekend sailors this has been the reality. The engines get professionally serviced each year, they are not run many hours, people avoid bad weather and they keep their boats where high quality fuel, parts and expertise are all available. As you go further and for longer, especially to remote places, this changes a bit with care needed over fuel quality and parts availability being more challenging as well as having to be more self sufficient in maintenance skills. So management of availability with diesel engines is only an issue for more adventurous, intensive cruisers.

On the other hand Electric motors require a far more hands-on management process for all cruisers as the battery capacity is far less than a fuel tank and the rate of charge from renewable sources far slower. This means planning ahead and that has a much bigger impact on those who have not had to do this least with diesel engines.

If I motor-sail now to speed the passage, will I have enough battery left to motor into the harbour or up the river? That means thinking about tides/currents and the weather (how much solar power will I generate during the passage).

It means thinking about what might be needed in the next few days. Suppose the wind gets up from a different direction, do I have enough battery left to motor away from the anchorage if it becomes unprotected tomorrow.

It means being very aware of both consumption and generation. If I run the watermaker then when am I going to recharge the batteries, might it reduce the ability to get in or out of a harbour.

It will mean changing passage planning. Probably needing to be more flexible. If the wind drops you might not be able to motor fast enough for long enough to make a tidal gate.

Many sailors using harbours such as Chichester, have a working assumption of motoring from deep in the harbour to the open sea whatever the tide is doing. That might fully use your battery capacity with an electric motor.

If you are cruising outside the tropics in the winter your solar generation might only be 10% of what you would get in the Bahamas. The total power you can use over a period of time will be dramatically reduced so you will need to pay far more attention maximising the generation eg adjusting the angle of your panels (actively pointing them at the sun to increase their effectiveness), to keeping them clean and free of shade.

In some ways this is going back to ways of the past when yacht engines were unreliable and not powerful enough to push you against an unfavourable tide so that you didn’t factor motoring and consistent/predictable passage times into your plans.

What we are doing to handle this?

On the technical side

  • Efficiency is key everywhere. A brushless electric motor is better than one with brushes. Switch to low power everything eg LED, self contained solar powered wind sensors, wind vane self steering.
  • Lithium batteries. At the moment Lithium-ion phosphate (LiFePo4) technology has the edge with higher capacity, faster discharge and charge rates, able to be more fully discharged without damage.
  • Simple and basic. We are starting with no fridge or freezer in the UK. No electric winches, no electric toilets.
  • Improve the sailing performance as much as possible. So we are replacing a back of mast furling system with slab reefing on a longer boom with a larger sail area supported by battens. We are looking to changing from a single point mainsheet to a track. We are cutting lots of weight from the interior and systems.
  • Adjustable solar panels that allow extra capacity be deployed at anchor and in calm conditions.
  • We are keeping separate banks of batteries for house and motor while having the ability to transfer energy from either bank to the other
  • We have invested in a significantly oversized anchor to reduce the chances of having to evacuate anchorages.


We are using Victron monitoring tools (battery bank monitor, mppt controllers) that give us the most data possible on past and present energy generation and consumption.

We are following a revised version of the tradition that the engine starter battery should be kept separate from the house bank. This requires larger battery capacity overall and some extra components, however, we believe that this complexity does give us the reassurance of being able to protect our motor availability. At the same time, when in a protected anchorage we can choose to charge the house bank from the motor bank if you have a few cloudy days and are using a lot of power (maybe for clothes washing, cooking, or hot water). On the other hand when leaving an anchorage we can charge the motor bank (albeit not very fast) from the house bank although with the understanding that might mean we need tot turn off the house items such as electric autopilot, or fridge & freezer or no induction cooking. So our version has has some separation but also allows us to run DC to DC chargers at anytime to be able to “steal” power from one battery bank to charge the other.


More than anything else having an electric motor with a fossil fuel free goal means having realistic expectations. We expect to

  • sail on passages, using the electric motor for marinas, rivers and tight harbours
  • have more variable passage times as we won’t be using the motor to keep consistent average speeds
  • work more closely with the tides rather than be able to motor against them
  • work hard at maximising solar generation by using additional panels that have to be moved around, by tilting panels to their most efficient angles
  • work hard at minimising consumption of all appliances
  • by motoring more slowly to significantly increase range


I’d started this several times as a post about the disadvantages of electric motors, but I’d struggled with it. That is because, unless you have an unlimited budget, the issues are all about attitudes and expectations.

If you believe in reducing fossil fuel use then the differences are entirely manageable.

If you are not concerned about fossil fuels and the climate emergency then the inconvenience of managing availability is going to appear a deal breaker.

The technology is changing fast and modern boat design trends (such wider beam carried aft, fewer ketch rigs) make it simpler to fit larger solar capacity. It is likely that over the next few years there will be further gains in battery capacity. Monitoring and Management will be more sophisticated and automatic. So gradually the need to manage availability will diminish, especially for weekend sailors as a battery bank that is fully charged at your home marina will cope with a weekend of sailing and motoring.

Food progress

Now that we are confident that our multi-cooker is going to be part of our galley it opens some extra options.

So in December we joined a group making bulk purchases from a co-operative, vegetarian wholesaler. Our best bargain was a 10kg (paper) bag of dried chickpeas.

We’ve been using these in quite a few dishes in the multi-cooker. Very tasty and allows a shorter soak time and fully reasonable cooking time.

Jane has now started the next step which is making houmous (a staple favourite of ours) from these chickpeas. Latest batch is much tastier than a lot of supermarket packets and will be easy to make on board.

We have a whole load of other pulses (although sadly sold in smaller quantities that come in plastic bags).

Not forgetting grains

We want to start experimenting with sprouting some of these as a way of getting fresh stuff wherever we happen to be.

We really love the variety and taste of these pulses etc that are cheap, last for ages and with a pressure cooker are so easy to cook. They are so well suited to living on a boat as they are so adaptable (providing you can keep them dry). We think it is well worth making sure you can renewably generate and store enough electricity to be able to use an electric pressure cooker. These are so much easier to use than ones that you put on a gas stove. Plus a really big advantage is that you can put the cooker in the cockpit to avoid putting steam or heat into the cabin (steam particularly a problem in cold climates and heat in hot climates).

We find it quite amusing that one of of our favourite YouTube channels were concerned that they would have to live on lentils, we don’t see it as a negative ๐Ÿ˜‰

A beyond our dreams yacht

The sailing channels are full of amazing boats. What used to be the sailing magazines that my Dad would buy have been replaced by YouTube channels like Yachting World.

Consistently they present, as if it were normal a world view that everyone will be buying a brand new boat and that these days nobody would consider anything smaller than 40 feet (and that only if it is a “modern” shape which gives about 50% more accommodation than a more traditional design).

So the boats they show off start at about ยฃ 1/2 million (over 20x more than we paid for Vida and nearly 10x what we will have spent by the time we retire to live on her).

So they are far, far beyond our dreams, expectations and none of them have much focus on sustainability in any form.

To be honest not many of them are very attractive to us either. We absolutely do not need or want so much space, we absolutely do not want our sailing to be totally dependent on electrical power for sail control (especially as they all require fossil fuel electric generation).

Yes, nearly all of them will be much faster than Vida (so what, we are not planning to race). Their huge, flat wide sterns and twin rudders will be give more control downwind. Yet the costs of these benefits are huge (mooring/haulout/storage/repairs/complexity etc etc). With our experience a 38 foot boat still seems huge and daunting, we don’t want more ๐Ÿ™‚

Yet, I admit that I have just watched a video of one boat that if you happen to give me would be awesome (even if I’d want you to give me the money to make her fossil fuel free).

Actually, I think you would need to give me about ยฃ5M. I could buy a 5 year old Garcia Exploration 45 for about ยฃ1/2M, keep another ยฃ1/2M to keep her and ourselves in luxury for the rest of our lives and then give the ยฃ4M away to assuage my guilt at such indulgance ๐Ÿ˜‰

However, there is a lot we can learn from such experienced sailors as Pete Goss and Jimmy Cornell that we can and are putting into practice with our work on Vida. Plus others that we feel they and the rest of the sailing world need to learn about sustainable sailing in the light of the Climate Emergency and connected issues such as plastic pollution.

So what are we trying to learn and implement?

  • Redundancy: For example by adding a Hydrovane wind vane self steering we have 2 rudders, 3 self steering options, 3 hand steering options. Similarly with two battery banks, multiple solar panel circuits, two inverters, two electric hobs etc we have few single points of failure. See my post “The problems of interconnected systems
  • Insulation. Very clearly the levels of insulation make the Garcia Exploration 45 very quite and comfortable. We can’t get anything like as much but we are replacing the traditional ply plus foam backed vinyl with a minimum of 10mm closed cell foam and we already see it making a significant difference.
  • Understanding. Garcia do a week of training for new owners and provide lots of documentation. We are building up complete hands on experience of just about every single part of the boat.
  • Maintenance. A boat you don’t have to keep fixing things on. Our route to a similar goal is quite different. We are doing it through simplicity. eg changing from 3 fossil fuels + electricity to renewable electricity only, removing every seacock (apart from cockpit drains), composting toilets, no refueling or concerns with fuel quality.

What can’t we do?

  • An Aluminium hull and watertight bulkheads making the boat pretty worry free where there is ice in the water (but we can’t see a fossil fuel free heating system that would cope with such climates anyway)
  • A swim platform at the stern. Going to “make do” by sorting the best possible boarding system on the side of the boat.
  • A full deck saloon. We will be making sure we can enclose our wheelhouse for full water protection if not as warm as being “indoors”.
  • Have as much storage space. But we are creating more by getting rid of the diesel engine and tanks, the gas cylinders and the paraffin tank. Also by having less space for long term guests.

What they can’t do?

  • A brand new boat can’t have the same low carbon footprint as a 42 year old boat. We are keeping a cost the planet has already paid from being thrown away rather than using new resources (I’m guessing that everything we put onto Vida in new resources will be dwarfed by the fossil fuel impact of a few tonnes of diesel used each year).
  • Make a brand new 45 luxury boat as unattractive to thieves as a 42 year old 38 foot boat.
  • Reduce the cost to get to ocean crossing by a factor of 10

Maybe it is just self-delusion but we really don’t watch these video’s of new or larger boats and feel we wish we could have one. Well maybe except occasionally a Garcia Exploration 45 with an electric motor ๐Ÿ˜‰

Sustainable Sailing ideas becoming more mainstream

This Yachting World article is heading in the right direction. Skippersโ€™ tips: Bluewater sailing secrets of the million milers revealed

Some key items such as reduced plastic and renewable energy get mentioned.

I’m still desperate for them to connect the dots between all those parts and skills needed for diesel engines with the fossil fuel usage and advocate dumping diesel power completely. For 25kg you could carry a complete spare electric motor that it would be straightforward to swap into use at sea. With some spare solar panels you could make slow progress after really major gear failures. Plus all those hours finding fuel, paying for it, cleaning it, cleaning filters, changing oil, fixing water pumps, maintaining seacocks, worrying about fires etc.

Also no mention of sewage from toilets and grey water going into fragile coastal habitats. Yet again the simple, low maintenance option of composting toilets with no plumbing and no dumping at sea is ignored.

Good but the options now available should make sailing around the world far less costly to the planet, to our pockets and to our time.

Now is the time to switch to really Sustainable Sailing!

Making Electric Motor plans

So, if we do decide to fit an electric motor what are we looking at?

We follow five sailing channels on Youtube who have fitted electric motors:

Our plans are different, in part because we are in the UK and so pricing and availability is different. In the UK there are a small number of suppliers who will fit complete systems but they are outside our price range (about the same cost as the boat). Unfortunately we have not found UK suppliers of sailing boat specific kits.

So we are looking at buying parts and installing it ourselves. However, we are also not wanting to be too adventurous, so we are looking at components that have been used for marine applications by others.

This is where we are at so far:

How powerful should the electric motor be?

Calculating what size of engine to get is quite complex. The nature of a boat moving through water is that the power required to move faster rapidly increases with speed, until the point where adding more power does not give more speed (probably around 7 knots/13kph for Vida). So there is no point in buying a really powerful motor.

On the other hand, when you are motoring into a strong headwind more power is needed for the same speed. While we intend to be cautious and avoid dangerous situations where we can, however, we recognise that the time when a motor increases your safety most, is when you have to motor away from a shore in a strong headwind (and if that is somewhere with a restricted channel or an adverse tide then sailing will be most difficult). At these times more power is needed for the same speed.

In the end a sensible rule of thumb seems to be to replace a 39hp diesel with about the same hp in an electric motor (although the two hp figures are not directly comparable for reasons I still don’t understand).

Fortunately, at slower speeds (using less power – so that the batteries last longer), a 40hp engine at 25% power isn’t very different in efficiency than a 20hp engine at 50% power (and will be less likely to overheat).

So we are looking at a 40hp motor, unfortunately that restricts the options in the UK as the most widely available motors are less powerful than this (or are designed for speedboats rather than heavy cruising boats).


Most 40hp DC electric motors run at 72 or 96 volts. A few run a 48 volts. Higher voltages mean that at the same power the wires can be thinner as the current is reduced. Electric motors draw a lot of power and so with lower voltages the current can be very high.

However, there are two disadvantages of higher voltages. Firstly, they get more dangerous. Secondly, they need more batteries. You get high voltages by connecting batteries in series. So four 12volt batteries in series gives 48colts. You need 6 batteries for 72volts and 8 for 96volts. That gets expensive! If you decide you want to increase your range you can add extra batteries in parallel to your battery bank, but if your bank is 96volts you need to buy 8 batteries at a time.

So we have decided to look for 48 volt motors and start with a relatively small bank of batteries that we can add to in the future.


Unlike Kikka and Dan on Sailing UMA we have decided to go for a brushless motor. More expensive, hard to find secondhand but safer as they don’t have the same risk of sparks (some authorities and insurance companies won’t insure boats with motors with brushes, especially if they have gas on board due to the risk of explosions).


Some electric motors are water cooled (typically using fresh water with a sealed system and a radiator). Others are air cooled, some with integrated fans.

Our preference is for air cooled for simplicity, we will have to make sure we provide an adequate supply of dry air to the engine room.

Motor of choice

So we are looking for a 40hp, 48volt, air cooled, brushless motor.

The US supplier used by Beau and Brandy is Thunderstruck-ev and they have a HPEVS AC35 motor kit. I’ve have found a UK supplier of these HPEVS AC motors. So yesterday I was able to pop in and visit Falcon Electric who are focused on electric cars. That takes us a few steps forward.

So we are looking at an HPEVS AC51 motor package from Falcon Electric which gives 40hp at 48volts. It comes with a lot of the stuff we need (Controller, Wiring harness and display).

Other stuff

Of course we don’t just need the motor, there are lots of other bits too.


We hope to be able to reuse the propeller and the propshaft (after the existing coupling has been cut-off).

We will need to replace the cutlass bearing (this is the bearing through which the propeller shaft enters the boat, it is typically water cooled by the sea). Once the existing engine is out this should be straightforward.

We are looking at replacing the original stuffing box (this is what stops water from entering the boat through the propeller shaft opening). There are much more modern, drip free, reduced maintenance options now available.

We will need a thrust bearing as electric motors are not designed to resist the push of the propeller.

We will need a way of connecting the motor drive shaft to the propeller shaft. This will probably need to be a belt with pulleys as the motor has a maximum speed of 10,000 rpm and the propeller is much less (probably in the region of 3,000). This is something we need to calculate as the propeller speed needs to be matched with the propeller itself and the boat hull shape/speed. In the US Thunderstruck-ev sell these, I’ve not found anything but suppliers of parts here.

The engine will need a mounting (at one end part of the gear reduction). Fortunately, there is a stainless steel fabricator at Beaumaris we should be able to use. With the gear reduction we should be able to position the motor reasonably high so we can be confident it won’t get flooded even if the boat took on a lot of water. We will sort out some form of cover to direct cooling air and make sure that air is as dry as possible (and it might be nice if we can choose to divert the warmed air outside in warm climates and inside in cooler places).


The dimensions of the electric motor are far smaller than the current diesel so we will be able to fit the battery bank in the same space (giving us loads of extra space where the fuel tanks are at the moment). We will start with a small battery bank, probably four 12V 100AH Lithium-ion Phosphate. When we see how that works for range we can decide how much more to add.

We need to plan exactly how we will handle charging. Probably the simplest (but not most efficient) will be to install a DC to Dc charger so we can keep all our renewable energy charging our house battery bank and then charge the engine bank from that. Otherwise the voltage switching and balancing gets a bit complicated.

Controls and monitoring

We want to end up with a simple, single lever control that controls both direction and speed (eg push forward to go forward with speed controlled by how far you push, pull backwards for reverse). We will need to sort out displays of battery and range that we can see outside. Obviously, these are slightly different for boats than cars (speed is an order of magnitude different for a start).


This is going to need more thought. There are lots of dependencies to work out. For example, we are going to need the yard to lift the old engine off the boat at least (we probably need to get it out from under the cockpit floor which is under the wheelhouse roof ourselves). However, as the yard is very full that will need to wait until some other boats have been launched in the spring. At least this will allow us to workout all the details before rushing into it.

Other advantages

  • We don’t have to learn how to maintain diesel engines ๐Ÿ™‚
  • We should be able to sell the existing engine for more now than in a few years time.
  • We gain lots of space in the cockpit locker
  • We gain storage space in the corridor to our aft cabin.
  • We don’t have to replace the water coolant seacock, we can get rid of it.
  • Access to the cockpit drain seacocks and bilge will be much easier
  • The boat will be lighter
  • We should reduce the amount of maintenance we need to do in the future
  • Fossil fuel free ๐Ÿ™‚
  • Much quieter when motoring
  • No Diesel smell (brilliant for helping reduce seasickness)
  • Zero fuel cost and much more independence from harbours when cruising


  • Cost (rough budget about ยฃ12,000)
  • Reduced range (depends on the size of the battery bank but certainly only a few minutes at full power initially)
  • Renewable generation limits. How fast can we charge everything? We are going to need to cover the boat with solar and move them around to maximise power generation.
  • Restricted cruising grounds by availability of enough sun to charge everything – we might need to go south for the winter ๐Ÿ˜‰
  • With electric cooking, electric dinghy motor and this electric motor we will need to carry petrol generator in case we can’t keep up through renewable generation.

The problems of interconnected systems

I’m not writing about IT or programming here (although there can be similar problems).

By this I’m thinking of Single Point of Failures (SPOF) and taking that a bit further. By SPOF I mean the danger of one item failing and causing a cascade of failures. For example suppose your hot water comes from the engine, your emergency bilge pump is powered by the engine shaft, your battery charging comes from the engine alternator, your hydraulic system for bow thruster, windlass and winches is powered by the engine. Then there would be lots of simple small failures that would cause everything on the boat to fail eg some dirty diesel blocks the fuel filter, the sea water cooling fails in any one of 10 different ways.

One of the shocking things when you look for SPOFs is how critical to your safety some very small items are. So far too much of Vida’s systems relied on the engine working (battery charging and hot water being obvious examples). Although the engines themselves tend to be very reliable there are far too many individual things that can stop a diesel engine from working (on boats the most vulnerable things are fuel supply and water cooling).

Generally though on boats as old as Vida (42 years) things were not very integrated. Modern boats will have far more integration of electrics (eg electric toilets, so any electrical failure and you can’t go to the loo) and also electronics (where all the instruments talk to each other but if the main data cable fails due to corrosion nothing works).

However, the area that is proving most challenging in terms of interconnected systems on Vida isn’t about direct connections, it is about space.

Back in the 1970’s boat hull shapes were very different to modern boats. They were much narrower overall and the stern particularly was much narrower (in fact modern 38 foot boats will have a stern that is about the same width as Vida is at her widest). Typically the sides are much more vertical with a hard(ish) transition from the side to the bottom, Vida is more of a wine glass shape. The modern boats have a lot more height above the water (less depth below the water but not by as much).

All this means that there is far less interior volume to fit everything in. Our centre cockpit exacerbates this problem (but is still a design feature that we love and a key reason for choosing Vida).

So getting to the point, the over all boat shape combined with the centre cockpit and through access to the aft cabin means that they suffered from a real lack of space for “machinery” (engine, batteries, water systems, bilge pumps, autopilot, fridge compressor). I suspect that if the production run had been longer than about 6 boats they would have made changes (indeed one of the drawings shows making the galley larger so it is a U shape rather than an L shape – that would have helped this problem a lot).

What the lack of space for all the “machinery” did was create a whole host of problems caused by the various systems getting interconnected by being squashed into a very limited and inaccessible space.

They wanted to have a cockpit locker on the port side as the passageway to the aft cabin means there is no space for one on the starboard side. Storage for gas bottles, sails, fenders, rope etc etc is very limited so they made the locker as big as possible. However, that meant squashing all the “machinery” either under the cockpit locker floor (diesel tank and batteries) or forward of it (underneath where you stand when steering).

What we have found that this meant was that we couldn’t inspect, maintain or replace lots of machinery directly because you couldn’t get access until you had removed other items.

For example to remove the hot water tank (calorifier), which the electrics for heating were condemned in the survey, we had to do the following:

  • Empty the contents of the cockpit locker
  • Remove two levels of floor in the cockpit locker (and all the stuff hidden under the first floor)
  • Disconnect and remove four 12 volt batteries,
  • Disconnect and remove one (very rusty and leaky) paraffin fuel tank for the heating system.
  • Disconnect and remove the pump for the domestic water system
  • Remove the wooden shelf for the water pump
  • Cut out a wooden post supporting the cockpit floor where the person steering stands
  • cut away the top of the wood cradle for the hot water tank
  • disconnect the wiring
  • disconnect the domestic cold water in and hot water out
  • disconnect the two hoses from the engine (which used the hot water from the cooling system to indirectly heat the domestic water)

Having removed all this we now have access to be able to replace the bilge pump hose, also to replace the hose for the cockpit drain (perished where it clamps to the drain and also clearly partially blocked), also to get to the vent hose for the main water tank.

My point is that, because all these systems were packed into such a tight space, with inadequate access, they all became interconnected. If anyone of these failed while at sea a repair would be very difficult. Potentially dangerous so many potential failures could disable the boat completely (at least if a repair was attempted).

There would be no point in carrying a service/repair kit for the water pump if installing it would mean taking all the batteries out of the cockpit locker and the heater fuel tank in order to be able reach it. To do all that while at sea would be very dangerous (eg no engine or instruments while the batteries are disconnected; let alone the danger of lifting heavy lead acid batteries out of a locker onto the deck in any kind of rough weather).

This is why our new plumbing system is not using the engine for hot water (and also because eventually we won’t have a diesel engine anyway) and is all being located under a seat in the saloon. We lose a very useful food storage space but suddenly all the plumbing is accessible.

Obviously we are potentially creating a new set of SPOFs by relying on electricity for everything (cooking, navigation, heating, water heating etc). However, we are trying to minimise this by the way we do things. For example:

  • Using busbars to connect 3 batteries in parallel means any one battery can be easily disconnected without affecting the wiring of any of the others, without affecting the voltage (just the capacity).
  • Using multiple solar panels and multiple MPPT controllers
  • Using two 2,000 watt inverters instead of one 4,000 watt
  • Using two individual 2,000 watt hobs instead of a double hob

We are also very focused on making sure we have easy access to everything. That is helped by getting rid of stuff which took a lot of space and needed to be accessible (hot air heating ducts, seacocks for toilets, basins, sinks, gas bottles, hoses and cut off taps).

Living aboard a boat and sailing it around is often likened to “doing boat maintenance in exotic places”. It is amazing how much YouTube video time is taken by shots of people stuck in lockers or around the engine trying to fix things. Also the jokes when experienced people look at potential boats and joke about how much time they will spend in the “engine room” and how comfortable or not that will be.

So I’d much rather have far less integration of space (and systems) so that when maintenance is needed it is simpler and less potentially dangerous. Against this the cost of losing some storage space to make things more accessible is a small price.

Fortunately, it seems that the more sustainable choices have a nice side effect of reducing this integration and dependence Composting toilets are a great example. They have no integration with or dependence on anything else (eg no plumbing connections at all). So lots of nasty (as in particularly smelly) points of failure are eliminated. Plus no need for any access to or maintenance of hoses, joints, pumps and seacocks.

As is often the case sustainable choices have all kinds of side benefits ๐Ÿ™‚

A helpful example from Sailing SV Delos

Sailing SV Delos is one of the big, successful YouTube channels. We have just been watching a series on their electric setup after they switched to Lithium batteries and induction cooking a year ago.

They have been sailing around the world for more than 10 years in a much larger and more complex yacht than Vida. Their key motivation for this change seems to have been to get rid of propane due to it’s inconvenience (filling up around the world with many different connector standards), unreliability and dangers.

Our initial solar setup isn’t going to be very different in size (although ours are going to be less fit and forget due to the limitations of where we can put them). Our battery bank is a bit larger and will be 12volt rather than 24volt (for reasons which are complicated and which I’d rather not be the case, but it was driven by space and finances as much as anything).

However, we are not planning on connecting to shorepower, not going to have a generator nor are we expecting much changing of the domestic bank from our engine (because we don’t want to become reliant on the engine given that the goal is to use it as little as possible and replace it with electric as soon as we can) . This should be fine until we get to being liveaboards (not for a few years yet) but by then we will have a much better idea about both consumption and generation (very little to go by on large boat solar systems in the UK).

Fortunately, with only 2 of us and far fewer electrics (they have 4 busy videographers with their computers, plus freezer and a couple of fridges, electric toilets, and only an electronic autopilot) our consumption should be much reduced.

Anyway enjoy these 3 very helpful videos (with 4 more to come in the series):