Adding more simplicity :-)

We have been busy with the rest of life this month (September is always a very busy time at work for us both).

However, our thinking has been progressing and we have been finding lots of inspiration from very small boats and from other people’s projects. So for example this video from Sailing Magic Carpet

It ties in with our Foredeck and Forecabin plans update or at least it confirms that we are making some different choices.

Our chain lockers were quite similar. We totally agree on the need for more space for chain and for the weight to be further aft. Initially our plans were quite similar (see Plans for anchoring). However, this is where we have been able to simplify things a lot.

A combination of things have meant that we are completely changing our forecabin, it will be a lot simpler in many ways. We started that thinking in Foredeck and Forecabin plans update but we can now go further.

The two key things that have led us to a simpler solution are Water and Beds.

Water

When we decided to remove the stainless steel water tank and use some of the space for our batteries we have been through a number of ideas for water tanks. Now we have realised we can build them into the hull and this gives us huge advantages:

  • far greater capacity as no wasted space
  • much safer. They strengthen the hull and create extra crash boxes

We also realise that we can use the same technique for the batteries (rather than a drop in box build it into the bull), for the chain locker and for storage/crash boxes.

Beds.

Already we have reduced the number of beds by removing the fold out pilot berth above the starboard settee (it has saved weight and created a much more usable space). We have also replaced the “V” berth in the aft cabin that worked best as a 2 singles with one double Pullman style berth.

When we realised that the “V” berth in the forecabin wasn’t actually long enough for an adult, let alone 2 it simplified things a lot. It also means that we have a chance to create a much better chain locker than Magic Carpet 2.

So.

The key limit on the “V” berth length was avoiding having the chain pipe come down through the middle of the bunk. By moving to one single bunk we can move the chainpipe slightly to starboard so that there is plenty of space for the single bunk to extend past the chainpipe on the port side. Not only does this make the bunk full length and a good width it also means that we can use the chainpipe to drop the chain vertically into the chain locker despite moving it aft. That is a huge advantage over our original plans and what Aladino can do on Magic Carper 2 where the chain slides into the chain locker almost at the bottom – the chain can stack better, be further aft and have a deep crash box forward of it.

I’m now planning 4 watertight areas under the original”V” berth height. Each of them will be considerably higher than the waterline and all of them will be able to have a removable, watertight lid.

At the very forward end there will be a proper crashbox that we will probably fill with foam (there will be another forward of this beyond the foot of the bed that will also be filled with foam). These crashboxes will mean the whole bow from below the waterline to the bow roller will not be able to flood the boat if damaged.

Aft of the crashbox will be the chain locker. When at sea we will disconnect the chain from the anchor and attach a line between a deck bung for the chainpipe and the chain which will drop down to the locker. That will allow a watertight lid to be fitted over the chain locker. The bottom of the anchor locker will drain into a much smaller locker aft of it. This will have a pump to remove any water that comes in to the chain locker with the chain. This small locker will also have a watertight lid so that the two act as another crashbox.

Aft of this will be a full width built in water tank. The top of this will be the “footwell” when sitting on the bunk. It too will act as a crash box so a hole in the hull here will contaminate this water but not flood the boat.

The doorway into the forecabin will no longer be full height. The bottom will be level with the top of the water tank with a step in the heads compartment so that you can get up and into the cabin (no standing headroom but full sitting headroom on the bunk). The heads compartment will be your dressing area. There will be a door for this cabin, separating it from the heads.

Additionally, I want to learn something from the older Amels (like Delos). So we will carry a sheet of wood that can be bolted over the doorway on the forward side of the bulkhead. It will have a rubber seal so that the whole forecabin can be turned into a watertight crashbox. I can imagine that when sailing with only the two of us we might put that in place quite often when at sea (and just use the forehatch for access to the forecabin as a storage area.

Simpler

By embracing the limits on the size of the forecabin which mean a V berth for two adults isn’t practical we end up with a much simpler, stronger and safer boat that will suit our needs much better. We don’t need to be able to sleep 3 couples and 2 singles on board, but we do need to carry enough water and would like extra protection from potential damage caused by debris floating around our oceans.

Thinking about this has also helped us think about simpler supports for the Bow Roller, Anchor Windlass and Inner forestay. So we can hopefully progress them soon.

Once I can get the companionway steps removed, this approach of watertight compartments built into the hull is going to make the battery boxes much simpler and more compact. I think the outcome will be larger water tanks and being able to move the Inverter and Mains Galvanic Isolator into the motor room so that we can keep the wet locker behind the steps.

It takes a long time to simplify things, but the results are well worth it.

Battery bank installation progress

Today has included a huge amount of lifting and moving. A large part of that was lifting all 8 batteries on board. You can see the preparation for this in Low down progress

First battery bank has a nearly finished box (needs final epoxy coating and painting plus a lid).

The second battery bank will sit on top.

We need to make some changes to the floor supports. We will fit a new central floor board that will be the watertight lid of the top battery bank.

The top bank will also be 4 batteries and is both longer and wider than the lower bank. The hull shape means the batteries take up a lot less space this way round. Fortunately we have bluetooth access to the BMS of the lower batteries (and the top one that will be under the steps).

We are going to make sure that even if the bilge filled with water our batteries would not get wet (and there will be no exposed battery connections under the water at that point).

Anyway the bilge that water flows into is nearly a metre deeper that where the batteries are, that bilge will have an automatic electric bilge pump, a high water alarm and a manual bilge pump.

Low down progress

On Saturday we managed a few jobs that are about as low as we can get.

Water getting low in the wrong places

During the heavy rain on Friday we discovered a key source of the water in the (very deep) bilge at the aft end of the keel. I’d left a few holes in the floor of the anchor locker when we had removed the old windlass and chain guide. So water getting into the anchor locker was falling into the chain locker, from there it flowed down a hose (so that it gets past the shower sump) onto the front end of the keel (where we had cut the old hose so for the first time we could see the water coming in, when we had the floor up).

So I filled the holes and we went down in the depths (currently about 1m below the electric motor frame) and pumped out 5 buckets of water (we had removed a lot more with a temporary bilge pump a few weekends ago).

Battery storage on the keel

With a dry bilge we did some cutting and planing of the battery box we had started months ago (when the 120AH batteries were going to have to sit above the motor). It now fits on the keel under the companionway and saloon floor.

It just needs ply ends, epoxy coating and the batteries installing. A battery box for the 4 x 300AH will sit on top of it (one of these batteries will be behind this and a bit higher as it is behind the ladder and the space is not wide enough at that point).

Fortunately all the lower 120AH batteries and the 300AH at the aft end have bluetooth enabled BMS (battery monitoring systems) as these will be quite inaccessible. The other 3 x 300AH will be easily visible to check.

We will make these boxes as watertight as we can and they will be fixed in place so that there is no danger of a couple of hundred kilo’s of battery smashing everything and everyone should we ever be rolled over.

We have also done some detailed design work for how we plan to connect the battery banks. We are (seemingly unusually) planning to keep them entirely separate as it isn’t a good idea to combine different sizes of battery into a single bank. We want the flexibility of using each bank for either house or motor depending on need. However, never both connected to either house or motor at the same time. We also want to be able to direct the solar panel charging to either bank according to need. The 70A mains charger built into the Victron MultiPlus II will always go to whichever bank is connected to house (so when we connect to mains we always put the most depleted bank as the house to get charged first) .

Water in the right places

We think we can fit a 70 litre water tank in front of the batteries and an 18 litre one in front of that. Plus another 18 litre tank under the aft most 300AH battery. Finally one more 18 litre tank in the forward top half of the bilge under the motor.  That makes 124 litres nice and low down that will all be fully plumped in (you get a set of taps to choose which tank the water comes from for a tap or the shower).

In addition we think we can fit 4 x 25 litre portable water tanks above the propeller shaft aft of the motor. As well as taking us to 224 litres in total, these will be convenient for collecting water in the dinghy (providing we take a trolley to save carrying them by hand).

This should be plenty of water for coastal cruising but we still need more (and would like a watermaker) for ocean crossings.

Dave not getting stuck in the bottom

Using a temporary “ladder” I went into the cockpit locker to check the setting on the dehumidifier and the position of the forward mizzen chainplate.

Low on money

Well not so much low as actually sitting down to price all the things we need to be able to launch in March 2022 (in time for a 3 month sabbatical). It is a long list, however, it looks manageable and there are not so many unknowns now. Actually a bit of a confidence builder.

Lower Mast

Next will be back to tasks to get the mizzen mast (the lower one) back up but with dyneema rigging. In part that is to prove the chainplate and rigging design but also so that we can sort out the windvane self-steering, pushpit and aft solar panels. We still need to finish the new supports for the foot of the mizzen mast, cut and fit the backing plates for the forward stays and running backstays. Also need to finish repairing the pillar drill to make the tangs (and order the bolts for them). Then we can add the FR4 backing plates (and the on deck “mushrooms”, do the drilling for the chainplate dyneema loops and then make all the chainplate loops and shrouds/stays.

All that will allow us to finish the aft cabin, at least for the moment. The bed head needs finishing as it is part of the mizzen mast foot support. We need the step onto the seat to get to the bed, cabin sides need insulating (ceiling etc can wait as can the headlining). Then a quick paint and we can move back in (hopefully the work Jane is doing at home to remodel the bed mattress will be finished).

A restful wet day

We had a wet journey here and it continued to rain until mid evening.

In fact as we parked several puddles decided to flow into the area we parked in, close to the boat. So after trying to jump to get to the boat with dry feet I simply swapped trainers and socks for crocs are bare feet by that time it was ankle deep.

So after a very busy and physical week it has been good to rest, to update our budget and check a few things.

The battery box we built thinking it would go above the motor will fit as a waterproof battery box on top of the keel right in the centre of the boat. So 4 x 120AH Lithium Iron Phosphate weighing 56.8kg as low as possible.

Above that will go another waterproof box for the 4 x 300AH LiFePO4 batteries. They weigh 150.8kg. They wouldn’t fit in the same orientation if they were the bottom layer which means there would be a lot of wasted space.

Instead of the wasted space there will be room for a smaller water tank in front of the battery boxes. We will need to add extra water tanks elsewhere so that we have enough capacity even for a Pacific crossing.

This evening we have been watching YouTube videos and relaxing. Now high tide so will be lulled to sleep by the waves breaking on the beach.

Old water tank removed

We took a long time to decide that we would take out the original stainless steel water tank. As with lots of jobs it was daunting. However, in fact it was relatively straightforward. Using the man overboard block and tackle I was able to get it out whole.

Very glad we have done this. It was sitting in a bit of a puddle (looks like it blocked the last bits of water running into the deep section of the bilge).

We already knew the inspection hatches were grungy. We had seen some rust on internal welds. Now we can see that the welds for the baffles are rusting on the inside and outside.

So very happy we have done this.

We can see that we will be able to fit all our batteries in the aft part of this space, that keeps them together and the weight very low). Very happy with that.

We can then have a smaller water tank in the forward end (we will have other water tanks elsewhere). Having multiple water tanks is also a good safety feature. If there is a problem with one you haven’t lost all your fresh water in one go.

So very happy 😁 Jane is going to attack it with bilge cleaner now while I rest my back, that is mostly precautionary but I have had a few more twinges.

Now we are definitely going to 48volt house battery bank

This answers our pondering House Battery Bank: Should we go 48 volt

So we managed to get these two items from the clearance section at Energy Solutions.

The new MultiPlus II (looks like a decent upgrade from the original MultiPlus). Sized with a 48 volt, 5000 Watt inverter and a 70 amp charger. For the price of a much less powerful 48 volt charger on it’s own.

We had planned to have two smaller MultiPlus units to give some redundancy. We don’t really need that before we set off world cruising so we can wait and add a second smaller one in a few years. The feature set is amazing. For example we can have two power circuits on the boat and one of them will only be supplied if we have shorepower or a generator running. Also we can tell it the shorepower capacity and it will make sure it doesn’t overload it. It can do all kinds of clever stuff mixing shorepower, battery and solar in clever ways (that will mean that we can minimise our shorepower usage as the solar is prioritised).

The Isolation Transformer was an even bigger bargain, the case has some damage (looks like it was dropped onto one corner hard enough to bend the side and bottom panels). It can support a 32 amp 7.0kvA mains supply. It handles 230v and 120v, sorts reversed polarity and protects us from electrical currents that can cause metal fittings on the boat to corrode.

We are very much looking forward to getting these installed (might need to do some weight training to get the MultiPlus II up the ladder and it will need a very strong bulkhead to be fastened to).

Our Scandinavian challenges part 2

In Our Scandinavian challenges part 1 I covered the time/permission complications of getting to spend time in the fantastically beautiful (and remote) parts of Scandinavia and the Baltic given the impact of Brexit.

I ended with “In part 2 I’ll look at the other key challenges these cruising grounds have for us (particularly heating and renewable energy).” so here we are.

We are not (definitely not!!!!) planning to spend winters where the sea freezes unlike some of those crazy YouTubers I linked to in the last post 🙂 However, we are going to be spending time where some heating is going to be needed, whether that means wintering in the UK or being further north in the Spring or Autumn (either heading towards to back from a summer in or close to the Arctic). As we are going to be living aboard full-time in or retirement we want to give ourselves as many options as possible.

It should be no surprise that when it gets cold an electric boat that is aiming to have zero fossil fuels gets hit by a double whammy.

If the weather is cold enough to need heating then it is almost certain that you will get very little energy from solar panels (even on those bright sunny winter days the sun isn’t very high in the sky for very long).

If it is cold then you are going to need to heat the boat and all forms of electric heating use a lot of electrical power. Plus of course we tend to prefer hot food and drinks when it is cold and on a n electric boat that too will use lots of power.

So we generate less power but need more power. Ouch.

If we stick with a zero fossil fuels target then there are a number of options to help out but no magic solution:

  • Sail the boat to somewhere warmer 🙂 Given Schengen I suspect Turkey, Croatia, Cyprus and Algeria will be more popular for UK cruisers than they used to be. But the weather in the Mediterranean is no picnic, if anchoring you can end up moving often to find shelter from different wind directions. Winds can be very strong coupled with large waves that might come from a different direction. Another option is to go further south for example to the Cape Verde Islands, but then you could continue across the Atlantic to the best season in the Caribbean 🙂 But we do want the option to be able to winter in the UK so that we can visit family and friends.
  • Insulate the boat better. This is an obvious improvement that miraculously helps in both hot and cold climates 🙂 We have been working on going from zero insulation to a minimum of 10mm closed cell foam. See here for our first attempt to fit the foam – it didn’t stay up. Next plan is here but probably we will put more layers of foam to increase this to at least 20mm and reckon the purchase cost will be worth it in increased comfort and reduced energy use.
  • Heat locally. So rather than heat the whole boat do so in zones (we already have not heated the forecabin at all, in very cold conditions we could close off the aft cabin and stay in the saloon) and also use thicker duvets, heated blankets and hot water bottles (yes we won’t use a hot water bottle with an electric blanket!!) to avoid heating the cabin as much.

However, these are not going to be enough when it gets very cold.

We do have electric heaters (both wall panels and fan heaters). I think we will try some of the low power “greenhouse” style tube heaters under the bunks. That will give us 3 options to compare for warmth, control, comfort and energy use.

Despite all these efforts we are sure that in winter, despite all our solar, we will consume a lot more battery power than we can generate.

That leaves us with two more avenues to pursue. a) what other options are there to recharge the batteries b) what else can we do to make the battery bank capacity last longer.

What other options are there to recharge the batteries

One strategy that solves the problem is to spend time connected to shore-power. We have seen many cruisers on YouTube spend the winter in Marinas (Salty Lasses, Uma, MJ Sailing, Sailing Fair Isle are all examples). This way you get a permanent connection to mains electric. You can keep your batteries charged, have all your electric heaters running and stay warm.

But there are disadvantages. In the UK this quickly becomes costly (a winter marina berth for us will range from maybe about £1,500 for 4 months to £2,500 for up to 6 months that without going to the more expensive parts of the country where £800 a month would be a starting point). More than just the cost is that we want to live aboard our boat so that we can go sailing not sit in a marina for half the year.

So we want to explore options where we extend the time we can manage on batteries and go into marinas/harbours for a night every so often to get the batteries fully charged (and maybe have groceries delivered). It looks like we could expect to pay up to about £40 a night. One option would be to spend a winter along the South coast of Cornwall and Devon. There is beautiful sailing along that coast, lovely harbours, rivers and towns to visit. There are very lots of rivers with good shelter and many where you can anchor (eg Helford, Fal, Percuil, Fowey, Tamar, Yealm, Dart). Then you have a wide choice of marinas and harbours when you need to charge the batteries. If we can keep that under 10 days a month in marinas then not only do we get the sailing and beautiful views we also save money.

One obvious strategy will be to invest in wind generators, given that cold and windy weather often come together. They work out at between £1K and £2.4K per generator (remember we need 48volt ones). Calculating how much difference this can make is difficult, it depends how sheltered a spot you find and the weather conditions. We have a few options for where we might install one or more wind generators. It is important that we don’t end up casting shade onto our solar panels from the wind generators as that would have a dramatic impact on the solar performance. Also, as with the solar panels I would prefer to be able to take them down and inside if we are expecting a storm. If the demountable option works well then potentially we could have a position at the side of the mizzen mast that could be used when sailing. Then we would only put them wind generators up when the gain will be greater than the loss in solar due to shading.

As a starting point I’m thinking one wind generator using a demountable pole fitting towards the bow. With that we would only have the wind generator up while at anchor and it would be as far away from the solar panels and where we sleep as possible so that neither the shade nor the noise will be a problem. That will let us properly evaluate how much difference it makes. If we think it is enough then we could explore other options.

With our ketch rig the only option for that won’t cause shading and can be used both at anchor and when sailing is a permanent mounting on top of the mizzen mast. That doesn’t excite me. The top of a mast is the last place you want to add weight. It will also be moving around a lot in waves which will affect it’s performance. Finally, the foot of the mizzen mast is above the head of our bed. I’m concerned about noise and vibration disturbing our sleep. However, it would be out of the way and (until it breaks) very convenient. If we want that option to be available we need a generator that can be remotely braked (manually or automatically) if the wind strength is too high.

It is very hard to estimate how many nights in a marina having a wind generator would save us. We would have to save about 40 nights to recoup the cost. We could achieve that saving over a couple of winters if we could reduce the need to get shore power to once every 10 days instead of once every 5 days (both are guesses and will be very weather and location dependant). Of course it would also help avid the need for shore power a bit in other seasons, particularly if permanently mounted.

What else can we do to make the battery bank capacity last longer?

The most obvious answer is to install another form of heating that does not use the battery bank. All the YouTubers who have visited the Arctic Circle or Scandinavia in the winter have some form of heating that is not electric. They all say they can’t manage long at anchor otherwise. While our goals are not so extreme (the midnight sun is attractive to us but the sun not rising above the hills at all is not) we would be crazy not to learn from them. So what do they have besides electric heating (that they all only use when connected to shore power). There is a great video from Alluring Arctic on this, our takeaways from what we have seen are:

Wood burning stove

Uma have one of these and we have seen a few others. However, recent reports that we have seen on the high levels of pollution they release into the boat (mainly ash whenever you refuel it) and the air pollution from the chimneys mean we have ruled this out.

Diesel powered hot air

Probably the best known brand is Eberspächer, these install out of sight and burn diesel to heat air. Then then use a fan to blow the heat through the ducts around the boat. They are a more modern replacement for the paraffin heater we removed. The provide lovely warm dry air all around the boat. However, the ducting takes up a lot of space in lockers and they use quite a lot of electricity. Ran Sailing for example can only use it for one night or so before needing shore power to charge their batteries. Sailing Yacht Salty Lass have one and it is clear that these also require regular, quite time consuming maintenance to keep the insides clean and efficient. Obviously they need a diesel tank (and would normally take it from the main diesel engine tank which we don’t have).

So we are ruling this out for the loss of locker space, the significant electric use (which is what we are trying to avoid) and the amount of maintenance needed.

Drip fed diesel heaters

The brand that seems to offer heaters most suitable for us is Refleks. Their 66MW would fit neatly to a bulkhead which would be safe and not get in the way much. However, there are other options. The 66MV is insulated so it only heats the boat by hot water radiators, we could position that in a custom locker out of the way. The 66MK includes a stove top for kettles etc which would really help cut out electric consumption but I’m not sure where we could fit one. It seems some models can provide hot water for domestic use such as showers but I’m finding the information about which models do that a bit hidden.

As they are gravity fed they don’t use any electricity (I don’t think they even need a pump for the radiators?) and they are supposed to be very low maintenance.

We think at the moment a Refleks heater would be a good option. Whilst it does mean some fossil fuels it is far more efficient to directly heat the boat rather than run a generator to charge batteries to then heat the boat. It also gives a backup heat source should we have a catastrophic electric failure.

Conclusion

By combining lots of these options we hope to get to the point where we can cruise in Arctic summers, stretched Scandinavian sailing seasons and British winters while stretching out the time we can go without needing to connect to shore power.

We will work up to the full combination of insulation, localised heating, wind generation and a Refleks heater (hopefully for radiators in all cabins and hot water for showers) with the goal of being energy independent (with care and some help from the weather) for a couple of weeks at a time. Only time will tell. If nothing else works we can sail to the middle the Azores high pressure and bob around for a few weeks to warm up 🙂

House Battery Bank: Should we go 48 Volt?

While we wrote Going 100% electric: the “house” after Going 100% electric: the Motor we had in fact made most of the decisions around the house electrical system before we made the decision that we would go straight to an electric motor instead of the diesel.

Now we are thinking about making a change. The things prompting us to consider a change include:

  • The high cost of 48 volt battery chargers. We do need the option of charging our battery bank when in a marina or harbour (or even ashore in the boatyard). We can imagine spending sometime alongside in winter or even popping every so often just to get the batteries fully charged (the expectation of needing to live in colder climates in Winter is influenced by both Covid and Brexit which might limit our options for where we spend our time).
  • We think our house battery bank has ended up a bit small (4 x 120AH) and so are going to be needing to charge it from the Motor bank (4 x 300AH) quite often.
  • Having two battery banks at different voltages ends up creating quite a lot of extra complication.
  • With one exception (the anchor windlass) we have realised that our 12 volt usage is relatively low (LED lighting, boat instruments, water pumps).
  • While we have specified really thick cabling with big busbars and fuses, it is challenging to power 2 x 2,000 watt inverters from a 12 volt battery bank. The current that we need to safely pass is huge and this is where the vast majority of our house consumption will be (induction hobs, microwave, multi-cooker, watermaker, water heater).
  • We didn’t understand enough about how you can power 12 volt systems from a 48 volt battery bank. We thought they were too inefficient but have now realised that we either incur that inefficiency when charging a 12 volt battery bank from the 48 volt bank for all house uses OR when using a 12 volt house appliance (but not a mains powered item from a 48 volt inverter). The total losses are much smaller if we incur them only as we need the 12 volt power rather than to keep a whole batery bank charged.
  • We deliberately chose 4 batteries for the house bank that had enough output so they could be re-wired to be a 48 volt battery bank for the motor if the main bank failed. However, it would take ages to do. So a bigger 48 volt bank with two sets of 4 batteries wired in series and then the sets connected in parallel gives immediate access.

So a little maths about the issue with power over 12v cables.

P = power in watts (W)
V = voltage in volts (V)
I = current in amps (A)

Power = Current x Voltage or P = I x V

Switching it around we have I = P / V
So 4,000 watts from 12 volts = 4,000 / 12 = 333 Amps
Whereas on a 48 volt system we have 83 Amps

More amps = thicker cables and lots of care to avoid melting connections or high losses.

The disadvantages of changing from a 12 volt hour battery bank

Our current thinking

  • As we install them, we will configure all 8 batteries as a single 48 volt battery bank. This is pretty straightforward.
  • We will sell our unused 2 x 2,000 watt Victron Phoenix inverters (get in touch if you are interested).
  • We will use our Victron Orion 48 volt DC to 12 volt DC converter to power all our 12 volt appliances. We can always add extra Orion’s to run together if we need more power (eg for the electric auto-pilot)
  • It would be very expensive to add enough Orion’s to provide all the 1,500 watts at 12 volts for the windlass. So we will add a 12 volt battery close to the windlass. When the windlass isn’t being used we can charge the battery through the standard 12 volt system.
  • We will add 2 x 48 volt 3,000 watt Victon Multi-plus charger/inverters (2 of them to provide redundancy, we can run appliances with some limitations off one of them).

The Multi-plus inverters are smart. They provide mains power to the boat circuit and they automatically take that power from a shore power connection or if that isn’t available from the battery bank. When connected to shore power they automatically charge the battery bank. Two of them can put a total 70 amps into the battery bank.

We will have a 48 Volt battery bank with a total capacity of 1,680 AH (4 x 300 plus 4 x 120). Suppose we arrive at a marina with it fully depleted (ie down to 10% charge). That means we need to put in 90% of 1,680Ah which is 1,512 AH. At 70 Amps charging we are talking about 21 hours to fully recharge the battery bank (realistically we would expect many marinas to be limited to either 16A or 32A supplies so this will be a lot slower). Gradually we would expect marinas to upgrade their electric supply as the number of electric boats increases.

While there are costs to this change it does simplify a number of things, particularly with cabling and charging. All our charging goes into the one battery bank without having to switch solar panels between banks or do inefficient bank to bank charging.

It gives us much simpler use of the battery capacity as we can choose how we allocate the available power between house and motor. For example if we are not going anywhere and expect some sunny days in a while we can use all the capacity for the house. Or if we are motoring up a river to a marina all the house capacity is available for the motor.

In the long term we would expect more boat appliances to be available in 48 volt versions which will gradually reduce the need for DC to DC converters.

We haven’t made a final decision on this yet, but it does look like we are heading this way at the moment.

Avoiding engineering calculation paralysis

Two recent examples have in equal measures frustrated and amused me.

In their plans for Ruby Rose 2 Nick and Terysa have oodles of calculations but they appear to be aimed at justifying fitting large diesel engines because an all electric boat isn’t possible. They seem to have totally missed what was shown to be possible in their interview with Dan and Kika from Sailing Uma.

Then there is the subscription website “Attainable Adventure Cruising, The Offshore Voyaging Reference Site” with an article in the last week “Induction Cooking For Boats—Part 1, Is It Practical?” where I joined a discussion coming from our very different approach.

Both these present a numbers based “engineering” approach to decision making about the “practicalities” of moving away from fossil fuels. Sadly due to the initial assumptions the approach almost always leads to the conclusion that renewable energy sources cannot provide enough power for either propulsion or cooking.

The approach rejects working examples because they don’t present numbers in an “acceptable” way.

Our problem with this approach is that it is simply too easy to make assumptions about what is needed and the conclusion depends far more on the assumptions than on the calculations. In both these cases the assumptions are based on the expectations and lifestyle of a couple.

Ruby Rose have assumptions about never compromising on a luxury lifestyle with every modern convenience.

John and Phyllis have decades of experience cruising in high latitudes and strong views on what is safe and seaworthy. They have a stated goal of not considering anything that has not got a 10 year history of reliability.

Both these approaches are flawed if the goal is sustainability (or if budget constraints are tight). So if your assumptions are that you need to motor for an hour at full speed, and 500 miles at cruising speed, cook for a couple of hours every day, run a water maker, washing machine, multiple fridges and freezers, electric auto pilot, video editing laptops every day then you are going to conclude that renewable energy sources can’t cope.

Cynically if you control the list of things that you want to run all the time or anytime regardless of the conditions then you can guarantee that you will never be able to manage with renewable resources (at least until the last oil well has run dry and the Netherlands has disappeared under the sea).

Yet there is another way. One that we find most often from people with limited resources.

Embrace the limitations

Or start at the other end. Start with the resources that are possible.

  • What battery bank capacity can I afford?
  • What size battery bank can I fit (size and weight)
  • How many solar panels can I fit (and afford)?
  • Is wind generation going to fit my boat, my budget, my geography?
  • Is water power generation either from regen on an electric motor or something like Watt and Sea going to work (how much time sailing at suitable speeds)

These provide the constraints. Then sustainability becomes how you live within the constraints. There are plenty of options.

  • A vegetarian or vegan diet (as recommended as a key way of reducing our carbon footprint) can reduce the cooking energy significantly (no a roast chicken cooked for several hours is not required every week, if you want it then save your energy up first, or use a solar oven)
  • Set your passage plans according to the energy you have, probably slower (but then the whole point of sailing is surely to sail)
  • Set your cruising ground according to the season and energy available and required (so you probably can’t sail sustainably into an Arctic winter which is just a constraint, like the ones the majority of people live with all the time)
  • Have food available that doesn’t need to be cooked if you are short of energy (Huel and the like)
  • Plan to use appliances when you have the energy, keep the ones that have to be on to a minimum (eg freezers, fridges, autopilots).
  • Embrace the constraints. Do you really have to be able to do the washing, make water and cook for 2 hours on the same cloudy day – if yes then why?
  • To be honest the list is endless, we have gone in just a few years from it being normal to only use an engine in harbours to expecting to motor constantly for days at a time. From no refrigeration and basic hobs to dishwashers and ovens and drinks coolers in the cockpit.

The argument that it isn’t possible to live within the constraints of renewable energy is disproved by history. It is disproved by the examples already documenting their experiences eg Sailing Uma; and Beau and Brandy.

The challenge is to our assumptions, our privilege, our expectations of luxury. The opportunity is to open ourselves to the impact our lives have on others and to stop seeing ourselves as deserving something that our actions deny for others both now and in the future.