How about this solar powered achievement!
Electric Boat Completes All-Solar Generated Cruise to Alaska that is really impressive.
So much looking forward to seeing what we can achieve once we get to the solar part of our refit.
How about this solar powered achievement!
Electric Boat Completes All-Solar Generated Cruise to Alaska that is really impressive.
So much looking forward to seeing what we can achieve once we get to the solar part of our refit.
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.
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).
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).
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:
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.
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.
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:
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.
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.
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.
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 🙂
From the beginning we have been planning Solar panels fitted to the guardrails. We have seen lots of boats with Solar Panels attached to the guardrails. However, as we are wanting to have zero fossil fuels we need more solar than most.
We have gone for Victron 175 watt panels for the guardrails and will start with 2 each side (as a centre cockpit we have more length available without blocking our view).
Later we plan to add more, although the extras will probably only be put in place when we are anchored.
The goal is for the panels to be:
We have been through lots and lots of ideas for attaching the panels looking at all the examples we can find while trying to keep the costs and amount of work to a minimum.
The existing stanchions are too widely spaced to be used to directly attach the panels (and a little too low). The wires between them will not be rigid enough (and neither are designed for these loads in addition to the load if someone is thrown against them). So we looked at adding legs to support them panels but then everything was getting very complex, heavy and time consuming.
Currently we have just one stanchion between the pushpit and side gate. That length is plenty for two solar panels.
So the current plan is to remove the one stanchion and replace it with four. Two per panel.
The panels will have two wood beams across their underside and these will bolt a point along the long edge of the panel to the top of a stanchion. The panel can hang down from the stanchions in it’s stored position and a dyneema guy-line going up to a low fiction ring attached to the nearest shroud will be used to lift the outer edge of the panel to adjust the tilt.
The aftermost of these stanchions will be very close to the pushpit (the panel will overlap the first part of the pushpit). We will use dyneema lifelines and as these stanchions are taller than the rest we will have 3 lines at this point (top one goes up from the pushpit and down to the gate).
To remove a panel we just need to undo the two bolts and disconnect the dyneema.
It looks like it will be cheaper to buy carbon fibre tubes and make our own way of attaching them to the deck than to buy stainless steel stanchions and bases. Plus Carbon Fibre tubes won’t need any bolts through the deck but it will be a bit more time consuming to fabricate. However, it is something we can put off for a while – we don’t need this to launch.
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:
So a little maths about the issue with power over 12v cables.
P = power in watts
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
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.
Sadly, we can’t do much but plan at the moment. However, that does at least give us the opportunity to improve those plans.
In More on sustainability, I included a bit about Jimmy Cornell needing to abandon his attempt to sail around the world with zero carbon emissions. So another incentive to improve our plans.
This is what we have so far:
4 x 40 watt panels (total 160 watts) for the top of the wheelhouse roof. To be connected so that the two sides are in parallel reducing the impact of the considerable shading as the main boom is just above the wheelhouse.
4 x 175 watt panels (total 700 watts) to be fitted alongside the guardrails. They will be moveable, tiltable and removable. So we can have up to 4 on either side of the boat (to catch the sun). While sailing we should be able to have 2 per side (positioned about 3/4 of the way aft), with the option to drop them to be vertical (like canvas side dodgers but with a gap for water drainage below them) for docking or if waves are a problem. But there are plenty of people sailing with these pretty permanently mounted (eg Rigging Doctor, Millennial Falcon, Sailing Project Atticus). We can also remove them and store them below in really bad weather (recognising that ours are larger and hence more windage).
We have been exploring lots of potential ways of fitting these. Quite a lot will end up depending on how our budget goes over the next few years, we explored a cheap getting us started option using lightish timber struts. However we now have a better solution Simplifying guardrail solar panels.
By adding a solar “arch” (see below) we should have a grand total of 1460 watts. That is more than Jimmy Cornell, plus we will be able to rotate and tilt most of them to improve efficiency. Coupled with significantly reduced power consumption (only 2 people, wind vane steering, only one fridge, no electric winches etc) we think we are heading towards the right ballpark figure.
We have lost count of the number of design options we have been through. Here was one. It got pretty complicated as we work around all the constraints. Our fairly narrow stern, mizzen boom and need for Hydrovane self steering make the structure very challenging.
Our current thinking is to mount two 300 watt panels almost completely independent of each other (total 600 watts). Through a combination of rotating and tilting we will be able to position them for maximum efficiency while also being able to have them either clear of the mizzen sail (ie sticking out aft beyond the boat length) or safe for docking or storms (ie extending forward over the mizzen boom and aft cabin) at which point we would not be able to use the mizzen sail. They will also be removable, even at sea so that again we can stow them (probably on deck due to their size) if needed.
Our plan is to first shorten the mizzen boom as much as we can for the existing sails. Longer term we might get a new mizzen sail with a shorter foot but fully battened with a fathead sail (google images of Fathead mainsails), that would keep the boom further out of the way,
Then the implementation we have agreed with Hydrovane puts the actual vane a little higher than normal so that it is clear of the mizzen boom and sail (thus allowing us to tack without having to touch the vane mechanism).
The solar support will start with an upright carbon fibre tube in each aft corner of the deck (or possibly just down the transom a little), these will be positioned so that they are just clear of the boom as it swings across. They will have a diagonal strut going forward and another diagonal going across the stern. There is a vast array of carbon fibre tubes available up to 54mm diameter so we have some calculations to do. We will mount a smaller carbon fibre tube through the deck that will go down to the full where it will be epoxied in, this will stand clear enough of the deck for the main upright to drop onto it and be close to fully self supported, the struts will add more rigidity as a precaution.
The top 500mm or so will be above the diagonal struts and the top part will be filled with thickened epoxy. This is then a base onto which the pole for the solar panel drops. These Carbon Fibre Tubes are designed so that each size slides into the next size up. So the poles for the panels will be one size up from the fixed upright tubes. They too will have a thickened epoxy filling in key places but leaving 500mm open to drop onto the upright tubes. Connecting the tubes this way allows the upper section to be rotated or removed. We will have a hole for a pin will allow the rotation to be locked in two places (and will also stop the top tube lifting off).
A smaller tube will be fitted horizontally to the top of the solar panel upright. Using a smaller diameter will allow us to attach it by through drilling the upright for the horizontal to fit though. The joint area will then be filled with thickened epoxy to lock everything in place. The horizontal tube will only project out on one side of the upright (like an inverted L). Using the rotation and locking pin this can be forwards or backwards from the upright. This horizontal will be approximately 3/4 of the length of one of the solar panels.
To attach the solar panel we have two slightly oversized square tubes. These are the long enough to be fitted to the solar panel (going across the width of it). They have holes drilled in the middle, with short lengths of tube (next size up from the horizontal) fixed into them so that they can slide onto the horizontal tube. This attached the solar panel and allows it to tilt.
To support this we add a smaller tube as a diagonal brace between the upright and the unsupported end of the horizontal tube. At which point it will look a like we have a pair of gallows on the boat with solar panels on top 🙂
All the fixed joints will be created by smaller diameter tubes going through the larger, the smaller tubes will have smaller holes inside the joint so that when the joint area is filled with slightly thickened epoxy they get locked into place. We will also use epoxy fillets on the outside of the joints.
We will use dyneema guys to control the tilt of the panels with the option to use them to lock the rotation in other places than the locking pin allows.
To remove the panels we will use a halyard. We will rig it so that the pull is up a topping lift, that means as the upright tube comes free the whole thing won’t swing wildly about into the mast.
This give us multiple positioning options:
There are obvious concerns about having large panels relatively high in the air. However, there have now been multiple Atlantic crossings by boats similar in size to Vida with panels this size on solar arches.
We do recognise that our design is a little different due to the complications (mizzen and hydrovane). We do not think this design is possible with the typical stainless steel tubing designs. However, carbon fibre tubes can be used for a wide variety of purposes including masts and wind turbines, that support significant loads on unstayed uprights.
Unlike other solutions we have a variety of options do deal with different conditions. We are not creating a fit and forget solution but one that fits with our expectation of Active Solar Generation which we believe is a critical factor in achieving zero fossil fuels. The real potential to increase solar generation isn’t clear but a 30% increase is possible when you can angle correctly and far more if panels can be moved to avoid shading.
We can potentially add a similar pole support base on each side of the boat by the mizzen mast. In suitable conditions a wind generator can then be deployed. Again using the active generation principle. Wind generators are only effective in certain conditions, so why would we want the noise and windage all the time? However, they are the best option for reducing the need for a generator when we need electric power for heating while anchored in winter when there isn’t much sun.
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.
Or start at the other end. Start with the resources that are possible.
These provide the constraints. Then sustainability becomes how you live within the constraints. There are plenty of options.
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.
Our process for designing the electric motor compartment has had to be somewhat adaptable. We started from knowing nothing and so it has been a constant process of learning and then changing our plans.
The work over the last two weeks (Stuffing box flange is off, Yanmar Diesel 3JH5E for sale and Friday progress #21) has been a catalyst for some more changes. We now have a much clearer understanding of how all the parts between the motor and the propeller fit together. We also have a much better idea of what we need to fit (and many thanks to Tristan for his comments on our post Staycation Electric Motor Progress which got us rethinking our drivetrain).
So we are now close to deciding upon a PSS Pro Shaft Seal to keep the water from coming into the boat through the stern tube. We like this dripless seal as we shouldn’t need to provide a raw water supply to lubricate it. That is good because as our motor is air cooled we don’t have any raw (salt) water to divert into the seal. Some brands require 4 litres per minute which would mean installing both an extra seacock and a pump.
The challenge of providing water lubrication to the dripless seal isn’t just that we would need to provide it when the motor is running but that we would also need to provide it when sailing and using the spinning propeller to generate electricity using the regen feature.
So the PSS Pro shaft seal allows you to provide an air vented hose if your speed will be less than 12 knots (if we ever reach 12 knots it will be a short lived and no doubt terrifying moment!). However, if we find that water lubrication is required to reduce wear when running in regen mode for days at a time, then we can add a seacock salt water inlet and connect it directly to the seal without needing a pump.
The PSS Pro shaft seal is also available with a wider range of support for propeller shaft and stern tube flange sizes. We hope/plan to reuse the flange that used to hold the stuffing box, it is a larger diameter than would otherwise be the case and most dripless seals can’t cope with that.
So that is all good 🙂 The only downside is that the PSS Pro Shaft Seal is a bit longer than many of the solutions.
That brings us to then next piece of the puzzle which is where Tristan was so helpful. Our initial plans used thrust bearings within the motor frame to absorb the push and pull from the propeller. These have two grub screws that pass the thrust from the propeller shaft onto the motor frame and then that gets passed through the motor mounts to actually move the boat.
It turned out that as a very basic and cheap solution it was flawed. Two grub screws are not very much when it comes to transmitting the thrust generated by a 40hp motor spinning a propeller ar 1600 rpm to move 9 tons of boat. Also if the motor mounts need to transmit all the thrust to the boat they can’t be very flexible and so they won’t absorb much vibration.
So we are adding an Aquadrive to the drivetrain. This helps us in several ways. The propeller shaft ends at the Aquadrive which is fixed in perfect alignment with the cutlass bearing. So vibration and wear is minimised. The Aquadrive then passes all the thrust directly to the boat, so no thrust is acting on the motor which can therefore be mounted on much softer mounts so less vibration is passed onto the boat. Plus the connection from the Aquadrive allows for a lot of freedom in alignment for the motor requiring a less accurate installation.
Apart from the cost of the Aquadrive (nearly £1,000) this is all good. However, the impact on our layout is that the Aquadrive is over 250mm long.
With the PSS Pro Shaft Seal and the Aquadrive our motor needs to be moved forward so much that instead fitting the motor batteries (2 rows of 2) in front of the motor there is barely space for one.
So, we think we are switching things around. We will move the motor to the forward end of the motor compartment, a longer shaft will connect the motor frame to the Aquadrive. The motor batteries will then go aft of the motor above the shaft and Aquadrive (it raises them by about 200mm).
We will probably move the house bank batteries to above the motor to keep the weight distribution approximately the same fore and aft. The centre of gravity will be a bit higher although we think still lower than with the diesel and full tanks.
We have not tried to fully plan where all the electrical items will go (motor controller, and inverters are the biggest) yet.
The plan is to build from the bottom up. So
Fortunately, while the list is long the uncertainty is getting less. The biggest unknown is now how well the default program settings of the motor controller will work. Will we need to hire or buy the tool to reprogram it? Within that the biggest questions are about the regen and we won’t be able to know much about that until we are actually sailing.
So quite happy with all this :-).
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:
However, by committing to Zero fossil fuels we are increasing our electric consumption significantly and reducing our energy sources.
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:
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.
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.