The need for Active Solar power generation

With the our commitment to Zero fossil fuel sailing we have been having to review and update our initial Solar plan. Designing our Solar Arch has been part of that.

The traditional “passive” approach to solar is not going to work for us. By that I mean the idea of putting up a few solar panels and forgetting about them. We need to generate far more electricity from solar than this approach achieves.

So what do I mean by “Active Solar power generation”. Unlike shore based like people living on boats are used to being proactive about energy use and supply. So the mindset includes managing consumption and keeping an eye on battery state. However, for a long time this has been done with the expectation that you can always charge the batteries by running the diesel engine or a generator or by going into a marina and using the shore supply.

We are making a determined effort to keep electric consumption down through a number of deliberate choices:

  • Wind vane self steering, keeping the electric autopilot only for redundancy
  • No freezer. Yup it does constrain the food you can take and keep but fridge and freezer are huge electrical power hogs.
  • Reduced Computer consumption. We are going to be minimising laptop use by having Raspberry Pi single board computers for navigation, entertainment and “office work”. They run on 12 volt.

However, by committing to Zero fossil fuels we are increasing our electric consumption significantly and reducing our energy sources.

Increased consumption:

  • Electric Motor. This uses a lot of energy and is the opposite to the norm. When we motor we will be drawing lots of energy from our batteries rather than putting it in. While we will have regen (charging the batteries when the propeller spins while you are sailing) the change is incredibly significant as the norm is to see the diesel engine as a provider of almost unlimited “free” electricity and hot water. Of course it isn’t free at all, but more a desirable side effect that has resulted in a significant increase in the number of hours the engine is used. So has become a norm to motor whenever the wind speed drops because at the same time you will charge the batteries and heat the water.
  • Electric cooking. All forms of electric cooking (Induction hobs, Microwave, Pressure Cooker) use a lot of power (although mostly for a relatively short time). The norm is to burn bottled gas (occasionally diesel or paraffin). By cutting out another fossil fuel we increase our electric consumption.
  • Dinghy Outboard. We have an electric dinghy outboard engine. So far the boats we have seen with electric motors (Sailing Uma, Beau and Brandy) have not switched to electric outboards (despite the hours they spend maintaining their petrol outboards). In part that is because they want to be able to go faster in the dinghy (see this video from Sailing Atticus for a good reason for this) but it is also about the need to charge the outboard engine battery.

Increased generation

So this is the heart of the challenge. By committing to no fossil fuels all our energy needs to come from renewable sources. We have three options:

  • Engine regen. We are hoping this is going to be significant for us. On longer passages it will do more than recharge the motor batteries from leaving harbour but will contribute something to the daily consumption. It also has the potential to provide power through the night. However, it is only available while sailing and only while you are sailing fast enough (probably won’t contribute much below 5 knots). As liveaboard cruisers typically spend the vast bulk of their time at anchor the contribution isn’t that great.
  • Wind generators. These have the significant advantage of potentially providing significant power at night and through the winter. However, there are problems. Many people complain about the noise and vibration. Fitting them without causing shading on solar panels is a challenge. They do require a lot of wind, probably more than you would normally be looking for in a sheltered anchorage. We’ve looked at the Rutland 1200 but at the moment feel the cost and installation challenges are too great.
  • Solar. The typical installation of solar has been changing quite significantly. For liveaboard cruisers the norm now seems to be to have a solar arch with between 300 and 600 watts of solar panels. That is enough for minimal electric motor use (see Sailing Uma, Beau and Brandy or Rigging Doctor) but not for electric cooking, electric outboard etc.

So Active Solar

This is where our plan differs. We are going to have to be far more active about our solar generation. That means a number of things.

Our solar arch needs to be tiltable to increase it’s efficiency (both Sailing Uma and Beau & Brandy do this but the vast majority of solar arches do not).

When sailing we will need to be active in adjusting our solar generation. Some panel positions will be pretty much setup and forget (such as covering the upturned dinghy on the foredeck with panels before leaving harbour). Others will only be possible in lighter conditions (some along the guardrails for example).

The goal will be to have enough permanent solar when sailing (solar arch and wheelhouse = 510 watts) so that with the regen and battery bank we will be able to get through a gale when we have to put all the other panels below. That shouldn’t be too hard as in those conditions you are not likely to be doing much cooking and you can put off charging the dinghy outboard.

When conditions improve we should be able to sail in light to moderate with an additional 1,050 watts (2 x 175 watts on the dinghy, 4 x 175 watts on the guardrails from the cockpit to the stern. Some of this is going to suffer from massive shading at times so we are assuming it will be about 1/2 as efficient as the solar arch.

Then at anchor we need to have lots of solar panels that come out and are positioned dynamically. We will need to have solar panels positioned above the mizzen boom, around most of the guardrails and possibly above the deck. How many of these we will need is still uncertain (it depends so much on where we sail – if Coronavirus and Brexit mean we have too stay around the UK then we are going to need a lot more solar in Scotland than the Caribbean).

So far we are planning on a total of around 2,400 watts (13 x 175W + 4 x 40W) which so far I have only heard of on large catamarans.

We will need to be active in working with these panels. We will need to adjust the tilt during the day so that as the sun and boat move their efficiency is kept as high as possible. We will need to move them if other boats come alongside or if we are in a marina. We will need to put a lot of them below when sailing.

So I’m going to be building a standardised wooden surround for each panel. This will provide attachment points so that any panel can be fitted to any section of guardrail (and be tilt adjustable) or to the supports above the boom and dinghy. The edging will provide bump protection when moving them around and allow panels to be stacked without scratching the glass. We have chosen the 175W Victron panels as our standard because they are about as large as we can lift, manoeuvrer around the boat and fit through the main hatch into the cabin.

Exactly, where we will store all the panels that need to be “reefed” (taken down) in a gale is currently not fully sorted. Some might go on the aft deck or aft cabin. Some in the corridor to the aft cabin where one of the diesel tanks was. Some in the forecabin (which is likely to be mostly storage when there are only 2 of us).

We are under no illusions that we can achieve zero fossil fuel without ongoing, daily labour to maximise solar generation. But while that might seem a lot of work remember that we won’t spend any time (or money) finding and visiting fuel docks or carrying jerrycans around in the dinghy.

In summary

We believe we can capture several orders of magnitude more solar power than is generally the norm for monohull cruising yachts. But it will require us to work at it every day.

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.

Zero fossil fuel sailing


The goal for the environmental element of Sustainable Sailing has to be a zero use of any fossil fuel, at least for energy when using the boat. I don’t think we will be there in terms of all inputs for a long time yet (zero fossil fuel food supply or clothing or replacement parts as examples).

Starting point

When we bought Vida there were 4 fossil fuels aboard her.

  • Diesel: For the main engine providing propulsion when not sailing
  • Paraffin: For the hot air heating system (used batteries as well for fans)
  • Propane Gas: For cooking
  • Petrol: For dinghy outboard engine (petrol included, engine not)

Where we are at

So far we have removed 3 of these (Paraffin, Propane and Petrol). Two of these we have replaced with electricity (cooking and outboard engine) and we are confident that we will have enough solar power generation for these to be powered fully by renewable energy.

But here on the challenges get bigger. We haven’t replaced the boat heating system yet and we can only have hot water if we burn diesel in the main engine (which heats hot water as a side effect). We will be removing the current hot water system anyway as it is 42 years old, totally inaccessible and the immersion heater doesn’t work. It is less dangerous than the risk we had of paraffin leaking all over the engine compartment but it is a metal tank full of water right by the alternator that I can’t inspect. So it will come out.

So we need electric only heating and hot water. This is a significant challenge and I’m struggling to find examples of people who have done this at all and certainly not without running fossil fuel battery charging.

The main engine

So far I haven’t mentioned replacing the diesel engine with an electric motor. To reach zero that will be essential, but for the moment our plan is to simply minimise it’s use by a) improving sailing performance & our skills so that we use the engine less b) not relying on the engine for hot water heating or electricity generation. An electric motor will have it’s own battery bank. It will also have the potential to generate some electricity when you are sailing (water turns the propeller and the motor turns into a generator). So it can be possible (in some circumstances) to consider this a as a separate, self contained system (if like us you intend to keep motoring to an absolute minimum)

Challenges and calculations

However, there are more challenges. There are other significant electric uses and we need to limit the daily average electric consumption to the daily average renewable generation. At the moment we don’t know what the real levels of power generation will be (see the post on Solar generation for our current plans).

For the rest the calculations all get tricky because generation and consumption both vary according to the current climate/weather and activity (sailing or anchored). Unfortunately, in colder places in bad weather energy consumption will rise (as you want to stay warm and are less tolerant of cold water for washing) and solar generation will drop (less sun).

There are also significant differences between when you are sailing and when you are anchored (or in a marina or whatever).

  • Cooking: much less energy when sailing as tend to restrict hot meals and do simple one pot cooking.
  • Hot water: much less energy when sailing as showering will be tricky and so reduced, also little washing up
  • Lighting: Much more when sailing due to navigation lights and someone up all night long
  • Navigation: All instruments on when sailing. Particularly heavy users include Radar and AIS.
  • Autopilot: If using electronic (all we have at present) then a pretty high use when sailing

Other things will probably vary less when sailing or at anchor eg refrigeration and heating.

Contrary to what we expected it seems that the biggest challenges are not the high draw items (induction hobs, watermaker, windlass) that are run for small amounts of time but the things that need to run for long hours at a fairly constant draw (refrigeration, autopilot, navigation, heating). That is especially true if you can use high power systems when you are generating renewable energy with a fully charged battery bank.

Gaining freedom

One of the key advantages of heading for zero fossil fuels is the longer periods of independence possible as you don’t need to refuel. However, the three other key factors frequently limiting independence are:

  • Food: Not much we can do differently, however, if you choose you can stock up for longer periods if you are willing to sacrifice fresh food after a while.
  • Water: This is where a game changer is available. A watermaker (turns sea water into drinking water) can significantly increase independence and in many cases save money (as well as being higher quality and safer in many places). However, it uses a lot of energy.
  • Laundry: The two most common options seem to be a) laundromats (time consuming, quite expensive, reduces independence) combined with occasional hand washing when you run out or b) a standard home washing machine on larger boats.

The plans

I’m now going to review all the main electricity uses and what we are planning (or just thinking about). Of course at the moment many of these are provisional and will depend on what we find in the real world is possible in solar generation (and whether we go for other means of generation).


We are starting with 2 separate 1 hob induction cookers. We will have a gimballed tray so that one of these can be used safely when rolling around at sea. We are going for two separate hobs as this provides redundancy. It also means the gimballed tray is smaller. This way each hob is capable of 2,000 watts, when you have a double hob the total is less than 4,000 watts, either one hob is less powerful or both can’t be run on full power. We will look at other items in the more distant future if there is power to spare (oven, breadmaker etc).


Fridges and freezers can easily become the biggest users of energy when in the tropics. We don’t have anything at present so will be fitting a keel plate based fridge condenser (most efficient) and in our refitted galley will be creating a new highly insulated fridge space. We will not fit a freezer.


The three most common types of boat heating system are:

  • blown hot air
  • fuel burning “stove” typically diesel or wood
  • hot water radiators

I’ve found no examples of any of these using renewable energy.

The most promising option that we are going to try (it will at least work while we are in a boatyard with mains power) is an electric radiant heat wall panel. These are 240 volt and can work with electric socket thermostats/timers. They claim to be highly efficient. There are far too many unknowns at present to know how viable this option will prove to be, all we can say is it is the most promising option with the fewest energy losses that we have found so far.

Hot Water

The two options I have found so far are:

  • A “standard” marine calorifier (hot water tank with immersion heater and often additional heating from the engine cooling water), with the immersion heater potentially changed from 240volt to 12 volt or powered from the inverter. These need an expansion tank.
  • A 12v all in one water heater tank from Whale.

Getting hard information to compare these is difficult.


Before we start living aboard we will be installing a watermaker to increase our freedom from expensive marinas or lots of time and labour carrying water bottles to and from the boat. As water becomes more expensive and scarce this saves money and reduces demand on a limited resource in poorer communities. We will need to build a system ourselves from parts (cuts the cost to about 25% of a ready packaged system), the downside of this is a higher power consumption. Likely to be restricted to times when we are at anchor with the sun out


Our preference is to combine a hand powered washing machine with an electric spin dryer as allowing us to avoid the need for laundromats while keeping energy use way below a washing machine. The key benefits are:

  • Time: finding and using laundromats/laundry’s is costly in time, money and location
  • Space: a standard electric washing machine is much larger, not portable and will require permanent plumbing.
  • More suited to boat needs. The hand powered washing machines are robust and give good results. A spindryer will get clothes much dryer than the washing machines typically installed on boats.


Vida has very poor internal lighting (eg just 2 12v lamps in the main cabin), none of the lighting is LED. So we will be able to get much brighter lights that are more reliable and use far less power.


Currently the masthead light doesn’t work. None of the lights are LED so we can save power and gain reliability.

In terms of instruments the systems are very old. We are not going to rush to replace them but they are not complete and are not connected together. The total draw is likely to grow a bit over time. Plenty more research to be done.


Vida still has an original working Necco autopilot. They are supposed to be effective although we don’t know how much power it will use compared to a more modern one. We need to add an external on/off switch as the original broke and has been bypassed (it isn’t safe to have to go below to turn the autopilot on or off in an emergency). The controls are very limited compared to a modern autopilot. You have to set the compass dial to the course you want. The two key features we will miss compared to modern ones are follow current course and tack.

The good news is that it is installed in a really good way. The drive unit is completely protected from the weather and has an excellent connection via a chain to the steering rods.

For the short term we hope that this will be enough. If it fails then I would expect we would replace it with another electric autopilot. I can’t imagine us not wanting to have one. However, in the long term if we are finding ourselves making long ocean passages then we will be looking hard at installing a mechanical windvane self steering system as they work well without using any electrical power at all. We would probably fit a Hydrovane as it doesn’t need any connection to the existing steering system (which would be tricky due to the layout and space constraints). A hyrdovane also gives the option of attaching a very small/cheap electric autopilot to it as a backup, it is also the only common system that also acts as an emergency rudder if your main rudder fails (one of the most common worst case scenarios when crossing oceans).


We are upgrading to an electric windlass to raise the anchor (more in future posts). The current draw when in use is large, however, it is not used for very long and so we are not concerned about the impact on our power capacity.


As we look at what other people are using we are clearly aiming at the lower consumption end of the spectrum. No big audio visual systems, no scuba tanks, no massive computer power for continuous high quality video editing, no air conditioning, no bow thruster.


Our goal remains to get to zero fossil fuel dependency. So we will change the consumption side to match what we can achieve from maximising the renewable generation side. That will not just affect the renewable generation we fit but also where we cruise. For example if we can’t generate enough renewable energy to stay warm and comfortable in a cold climate then we will move to a more temperate one. If we need to stay at anchor for a few extra days to fully recharge batteries then we will do so.

Dinghy cradle

So Highfield provide a pdf download plan for a cradle to store your dinghy so that it is under least stress.

I’ve just knocked up one using the wood from the pallet that our solar stuff arrived on. It isn’t going to win any prizes but should be practical enough. The intention is that the cradle will fit in the van to make carrying the dinghy easier (the front section might need to be lifted a bit so that the front of the dinghy will fit between the front seats).

I’m going to add some rubber padding and if it works in the van will paint it so that it lasts a bit longer.

The Electric plan: Outboard

A key element of our goals for Sustainable Sailing (as we have hinted at many times) is going to be replacing fossil fuels with electricity with the assumption that the electricity comes from renewable resources. So this is where we are at so far:

Outboard Engine

Vida didn’t come with an outboard engine or a dinghy (at least one we think is suitable). So we have gone for an electric outboard. In many ways it seems like an obvious option. There are many obvious advantages of electric outboard motors to power a dinghy to make getting to and from the shore easy.


  • Replaces petrol with (renewable) electricity. The key and obvious win, should be enough reason on it’s own. We have to massively switch away from fossil fuels as an essential response to the Climate Emergency.
  • More portable. Compared to a petrol outboard engine this is so much easier to move. The battery is removable and so you end up with two parts that are both light enough for me to easily lift on and off the boat, in and out of the van, up and down the beach.
  • No spills or smells. Petrol outboard engines smell, the fuel tanks smell, spills smell. Petrol gets split and smells. Electric outboards have none of these issues. you can keep them anywhere in the boat without worrying about spills, they don’t have to be kept the right way up. You don’t have to make sure you have used up all the fuel in the carburettor to avoid spills.
  • Safer. No risk of explosions or fire! Petrol in enclosed spaces (like a locker, or in your vehicle travelling) is explosive.
  • More reliable. Petrol outboards are notoriously high maintenance and unreliable. Always needing servicing.
  • Simpler and easier. No difficult pull start, just turn on and twist the throttle. To reverse just turn the throttle the other way. Full torque immediately available without any need for chokes or warming up.
  • Waterproof. The battery actually floats, not just waterproof but if you drop it in the sea it will float! Compare this to the hours of video on YouTube of people having to rebuild their petrol outboards if they get dunked.
  • Silent. Especially useful for when we arrive late at night. We will be able to get our to the boat without disturbing anyone else.
  • Zero maintenance. Comes with a promise of being Lifetime Maintenance free


  • Speed. We are not going to be able to go anything like as fast as would be possible with a petrol outboard. The maximum size of engine for our dinghy is 15hp which will comfortably plane, the recommended size of 10hp will also plane if not fully loaded. Without paying silly money electric motors max out at about 3hp equivalent. So we will pootle rather than zoom. The only issue for us is the speed of the tide in the Menai Straits which will run faster than we can motor. We will just have pick times carefully or hug the shore to avoid the main tide.
  • Range. Essentially unlimited with a petrol outboard as you can always carry extra tanks of fuel. With electric once the battery is flat you are stuck until you recharge it. The range at full speed should be about 6 nautical miles (7 miles, 11km) which can be doubled by slowing down. We are giving ourselves some comfort space by having a 2nd battery, also by having both a fast mains charger (that we can take ashore to charge at almost anywhere) and a DC charger that means we can charge efficiently on the boat.

So we have bought an Epropulsion Spirit 1kW unit with extra battery from Nestaway Boats, doing so before the recent plummeting pound was reflected in the prices. We haven’t yet used it yet so more when we have. Meanwhile have a look on YouTube to see plenty of positive experiences.