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.

The biggest Electric Motor difference compared to Diesel

The biggest difference is availability.

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

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

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

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

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

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

What affects availability?

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

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

The three variables are:

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

What makes things easier?

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

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

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

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

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

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

What makes things more difficult

Tight and fixed deadlines.

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

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

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

Managing availability

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

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

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

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

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

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

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

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

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

What we are doing to handle this?

On the technical side

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

Management

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

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

Expectations

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

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

Conclusions

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

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

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

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

Food progress

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

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

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

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

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

Not forgetting grains

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

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

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

A beyond our dreams yacht

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

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

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

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

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

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

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

Actually, I think you would need to give me about £5M. I could buy a 5 year old Garcia Exploration 45 for about £1/2M, keep another £1/2M to keep her and ourselves in luxury for the rest of our lives and then give the £4M away to assuage my guilt at such indulgance 😉

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

So what are we trying to learn and implement?

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

What can’t we do?

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

What they can’t do?

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

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

Sustainable Sailing ideas becoming more mainstream

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

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

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

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

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

Now is the time to switch to really Sustainable Sailing!

Making Electric Motor plans

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

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

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

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

This is where we are at so far:

How powerful should the electric motor be?

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

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

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

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

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

Voltage

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

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

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

Brushless

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

Cooling

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

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

Motor of choice

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

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

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

Other stuff

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

Drivetrain

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

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

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

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

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

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

Power

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

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

Controls and monitoring

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

Timing

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

Other advantages

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

Disadvantages

  • Cost (rough budget about £12,000)
  • Reduced range (depends on the size of the battery bank but certainly only a few minutes at full power initially)
  • Renewable generation limits. How fast can we charge everything? We are going to need to cover the boat with solar and move them around to maximise power generation.
  • Restricted cruising grounds by availability of enough sun to charge everything – we might need to go south for the winter 😉
  • With electric cooking, electric dinghy motor and this electric motor we will need to carry petrol generator in case we can’t keep up through renewable generation.