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 🙂

Simplifying guardrail solar panels

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:

  • removable (so we can take them down and put them below in a storm)
  • foldable (so we can let them hang down alongside the guardrails when we are docking etc)
  • tiltable (so we can improve efficiency by improving the angle to the sun). This will also allow them to compensate for the boat heeling so we can keep the ones on the “downside” out of reach of waves.
  • stackable (we want the edges to provide protection so that we can stack them on deck or below without damaging the actual panel sections).

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.

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.

Continuing Solar planning

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:

Wheelhouse roof

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.

Guardrail mounted

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.

Longer Term Plans:

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.

Solar Arch.

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:

  • Preferred sailing option. Turning the panels aft so clear of the mizzen, with the ability to tilt them either for maximum solar efficiency or for minimal windage (compensating for the boats heel) depending on the conditions.
  • Preferred docked option. Turning the panels forward, the mizzen can’t be used but they are fully within the deck outline so not going to snag on other boats or be a hazard to people on the dock.
  • Moderately bad conditions. Assuming that you have taken the mizzen sail down, turn the panels forward and take the tilting control lines forward for maximum stability (better angle and braced to the deck rather than the support post).
  • Storm conditions expected (whether sailing, at anchor or in a marina). Lift the panels up so the uprights come off the fixed supports (using a halyard that has a low friction loop so that it runs up the mizzen topping lift giving a close to vertical lift). Lower to the deck and secure.
  • At anchor. Rotate and tilt so the panels are close to right angles to the sun, adjust to compensate for both the boat and the sun moving.

Safety

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.

Wind generators

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.

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.

Electric Motor compartment changes

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

  • Remove the old bulkhead to the corridor to ease access to the motor space. Finish the cleaning, then sand the whole area.
  • Fill the old seacock holes from the cockpit drains and the diesel water cooling (these will end up somewhat hidden by the battery box).
  • Paint the whole of the motor compartment and the cockpit locker.
  • Fit new Cutlass bearing (need to sort out grub screws to hold it in place), then the propeller shaft with the dripless seal. Add the (still to be fully cleaned) propeller and an extra zinc for galvanic corrosion protection.
  • Next will be the Aquadrive, which includes building the frame that will transmit the thrust. We should be able to fix this to the moulded in engine bearers.
  • That will allow us to mount the motor and fit the new shaft connecting it to the Aquadrive.
  • Now we will be able to fit the new cockpit drain seacocks where we can get easy access and route the hoses efficiently.
  • Then the battery box for the 48 volt motor battery bank of 4 x 300AH can be built above the shaft/Aquadrive.
  • Then the battery box for the 12 volt house battery bank of 4 x 120AH (position a little uncertain at the moment)
  • This will allow us to build the full bulkheads separating the motor compartment from the cockpit locker and from the corridor (and also steal a bit more space into the aft cabin).
  • Then we can fit all the electrical items and wire everything up (big job).

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 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.

Solar arch

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

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

But a solar arch on Vida is very complicated 🙂

We have three things that together make it very complicated.

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

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

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

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

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

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

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

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

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

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

Fortunately, we think it is going to be a lot harder to explain than it is to build 🙂

While the carbon fibre poles are quite expensive (over £700) everything else is going to be pretty cheap, so hoping to keep the total cost under £1,100. That for something that should be very strong, pretty light and give us really good functionality.

Sustainable Sailing and Human Power

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

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

What about using human power?

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

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

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

Moving the boat

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

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

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

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

Replacing electric powered items on the boat

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

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

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

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

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

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

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

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

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

Generating electricity

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

Getting to/from shore

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

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

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

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

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

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

Getting around on shore

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

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

Conclusion

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

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

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

Reduction gears for yacht Electric Motor

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

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

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

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

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

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

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

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

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

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

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

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

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