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).


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.


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).


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.


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).


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).


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


  • 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.

The problems of interconnected systems

I’m not writing about IT or programming here (although there can be similar problems).

By this I’m thinking of Single Point of Failures (SPOF) and taking that a bit further. By SPOF I mean the danger of one item failing and causing a cascade of failures. For example suppose your hot water comes from the engine, your emergency bilge pump is powered by the engine shaft, your battery charging comes from the engine alternator, your hydraulic system for bow thruster, windlass and winches is powered by the engine. Then there would be lots of simple small failures that would cause everything on the boat to fail eg some dirty diesel blocks the fuel filter, the sea water cooling fails in any one of 10 different ways.

One of the shocking things when you look for SPOFs is how critical to your safety some very small items are. So far too much of Vida’s systems relied on the engine working (battery charging and hot water being obvious examples). Although the engines themselves tend to be very reliable there are far too many individual things that can stop a diesel engine from working (on boats the most vulnerable things are fuel supply and water cooling).

Generally though on boats as old as Vida (42 years) things were not very integrated. Modern boats will have far more integration of electrics (eg electric toilets, so any electrical failure and you can’t go to the loo) and also electronics (where all the instruments talk to each other but if the main data cable fails due to corrosion nothing works).

However, the area that is proving most challenging in terms of interconnected systems on Vida isn’t about direct connections, it is about space.

Back in the 1970’s boat hull shapes were very different to modern boats. They were much narrower overall and the stern particularly was much narrower (in fact modern 38 foot boats will have a stern that is about the same width as Vida is at her widest). Typically the sides are much more vertical with a hard(ish) transition from the side to the bottom, Vida is more of a wine glass shape. The modern boats have a lot more height above the water (less depth below the water but not by as much).

All this means that there is far less interior volume to fit everything in. Our centre cockpit exacerbates this problem (but is still a design feature that we love and a key reason for choosing Vida).

So getting to the point, the over all boat shape combined with the centre cockpit and through access to the aft cabin means that they suffered from a real lack of space for “machinery” (engine, batteries, water systems, bilge pumps, autopilot, fridge compressor). I suspect that if the production run had been longer than about 6 boats they would have made changes (indeed one of the drawings shows making the galley larger so it is a U shape rather than an L shape – that would have helped this problem a lot).

What the lack of space for all the “machinery” did was create a whole host of problems caused by the various systems getting interconnected by being squashed into a very limited and inaccessible space.

They wanted to have a cockpit locker on the port side as the passageway to the aft cabin means there is no space for one on the starboard side. Storage for gas bottles, sails, fenders, rope etc etc is very limited so they made the locker as big as possible. However, that meant squashing all the “machinery” either under the cockpit locker floor (diesel tank and batteries) or forward of it (underneath where you stand when steering).

What we have found that this meant was that we couldn’t inspect, maintain or replace lots of machinery directly because you couldn’t get access until you had removed other items.

For example to remove the hot water tank (calorifier), which the electrics for heating were condemned in the survey, we had to do the following:

  • Empty the contents of the cockpit locker
  • Remove two levels of floor in the cockpit locker (and all the stuff hidden under the first floor)
  • Disconnect and remove four 12 volt batteries,
  • Disconnect and remove one (very rusty and leaky) paraffin fuel tank for the heating system.
  • Disconnect and remove the pump for the domestic water system
  • Remove the wooden shelf for the water pump
  • Cut out a wooden post supporting the cockpit floor where the person steering stands
  • cut away the top of the wood cradle for the hot water tank
  • disconnect the wiring
  • disconnect the domestic cold water in and hot water out
  • disconnect the two hoses from the engine (which used the hot water from the cooling system to indirectly heat the domestic water)

Having removed all this we now have access to be able to replace the bilge pump hose, also to replace the hose for the cockpit drain (perished where it clamps to the drain and also clearly partially blocked), also to get to the vent hose for the main water tank.

My point is that, because all these systems were packed into such a tight space, with inadequate access, they all became interconnected. If anyone of these failed while at sea a repair would be very difficult. Potentially dangerous so many potential failures could disable the boat completely (at least if a repair was attempted).

There would be no point in carrying a service/repair kit for the water pump if installing it would mean taking all the batteries out of the cockpit locker and the heater fuel tank in order to be able reach it. To do all that while at sea would be very dangerous (eg no engine or instruments while the batteries are disconnected; let alone the danger of lifting heavy lead acid batteries out of a locker onto the deck in any kind of rough weather).

This is why our new plumbing system is not using the engine for hot water (and also because eventually we won’t have a diesel engine anyway) and is all being located under a seat in the saloon. We lose a very useful food storage space but suddenly all the plumbing is accessible.

Obviously we are potentially creating a new set of SPOFs by relying on electricity for everything (cooking, navigation, heating, water heating etc). However, we are trying to minimise this by the way we do things. For example:

  • Using busbars to connect 3 batteries in parallel means any one battery can be easily disconnected without affecting the wiring of any of the others, without affecting the voltage (just the capacity).
  • Using multiple solar panels and multiple MPPT controllers
  • Using two 2,000 watt inverters instead of one 4,000 watt
  • Using two individual 2,000 watt hobs instead of a double hob

We are also very focused on making sure we have easy access to everything. That is helped by getting rid of stuff which took a lot of space and needed to be accessible (hot air heating ducts, seacocks for toilets, basins, sinks, gas bottles, hoses and cut off taps).

Living aboard a boat and sailing it around is often likened to “doing boat maintenance in exotic places”. It is amazing how much YouTube video time is taken by shots of people stuck in lockers or around the engine trying to fix things. Also the jokes when experienced people look at potential boats and joke about how much time they will spend in the “engine room” and how comfortable or not that will be.

So I’d much rather have far less integration of space (and systems) so that when maintenance is needed it is simpler and less potentially dangerous. Against this the cost of losing some storage space to make things more accessible is a small price.

Fortunately, it seems that the more sustainable choices have a nice side effect of reducing this integration and dependence Composting toilets are a great example. They have no integration with or dependence on anything else (eg no plumbing connections at all). So lots of nasty (as in particularly smelly) points of failure are eliminated. Plus no need for any access to or maintenance of hoses, joints, pumps and seacocks.

As is often the case sustainable choices have all kinds of side benefits 🙂

Building the battery box

So I’ve started building the new battery box at home. So far just a dry assembly. All the timber will be sanded and epoxy coated before using epoxy to glue as well as screws.

Apart from the plywood base (left over from settee bases) the rest of the wood comes from old Ikea bed slats.

Among the complications is the access. I’ve built as much as I can that will actually (hopefully) fit through the cockpit locker opening. This will be fixed into the extended original battery box and so will hold the batteries from moving forwards, backwards or side to side. Once all in place I’ll fix slats to stop them falling out if we ever get knocked right over.

Here you can see all that can be pre-assembled. The cockpit locker opening is about half the length.
First battery will be lowered in and slide forwards
Battery 2 goes straight down through the hatch.
Slats added to hold battery 1 down and provide a platform for battery 3
Battery 3 in position (fills the remaining space above battery 1). It does go a bit further forward as it isn’t blocked by the diesel fuel line.
Looking from above you can see all the battery terminals and the little Battery Management System displays.

The smaller battery for engine starting (which is still Lead Acid because it doesn’t need all the fancy features of Lithium) will be on the aft end (left in the pictures) on the top of battery 2. It will be in a sealed plastic box as unlike the Lithium batteries can leak.

Once all these batteries are all in place I’ll fix the busbars (copper bar that the battery terminals connect to) above forward end of battery 2 (right next to the lead acid battery box so they don’t cover battery 2’s terminals). 6 identical cables (3 red and 3 black) connect the batteries to the busbars (this way we can ensure the batteries are evenly charged and discharged).

From the busbars for our supply we run 2 big cables for +ve and 2 for -ve to the main switch , due to the high current demands. The -ve cables will have a shunt in them (used to measure battery condition and use). From the main switch we go onward to the inverters, windlass and 12 volt system.

Also from the busbars we will run a slightly smaller pair of cables to a common connection point for all the solar and wind controllers (that keeps the cable runs to the batteries much shorter).

Once the cabling is in then I’ll add a waterproof top and seal it off from the cockpit locker and engine compartment (with sound insulation to the engine side).

Quite pleased with this. The main struggle at the moment is to find a supplier for tinned copper bar (50mm x 6mm should be about right) to make the busbars from.

Gentle start to Friday #9

A quiet and gentle start today after a busy week.

First job has been to fit our 2nd Radiant wall panel heater. This is 320 Watts and is in the main cabin (no printed image at the moment). Again using a radio thermostat and timer that controls the 13 amp socket that the heater is plugged into.

Of course when not posing for pictures the thermostat isn’t tight next to the the heater.

We won’t know for quite a while whether we can generate enough electricity to use this when afloat. However, even if we are only able to use it when in the boatyard it is still a cost effective way to heat the boat.

Of course the real benefit is when the electricity comes from renewable energy. We have no control over the boatyard electricity supplier, which is why running it from our own system would be preferred.

I’m working on long term plans to automate the maximum use of our renewable energy when the boat is unoccupied. Even in winter our full solar panels (when installed) will be far more than is needed to keep the batteries fully charged. So normally a lot of the solar power will be thrown away.

Our Victron solar panel controllers (MPPT) have an open interface and tools so that a computer can talk to them. So does our Victron battery monitor.

How can we use that? Well I’ve started playing with Raspberry Pi zero w computers. I’ve used bigger Raspberry Pi’s before, but these are tiny. I can connect temperature (and humidity) sensors. I can control mains sockets and I can get information from the Victron systems.

So eventually I should be able to have a Raspberry Pi in each cabin measuring the temperature and knowing roughly how much energy can be generated each day. It can then control the heaters to use exactly that much energy so that the boat is as warm as possible while still fully recharging the batteries each day.

I’m also going to be able to use Raspberry Pi’s to run our navigation systems (using something called OpenPlotter), act as a media player, general purpose computer for Internet browsing, wordprocessing etc. All with a far lower power need than a PC or laptop and no moving parts. Plus very much cheaper and more reliable.

[UPDATE] The heater is keeping the main cabin at 19 degrees C, even with the hatch open (the cover for the wheelhouse is nearly fully closed). And we can see snow on the mountains 😍

More clearing progress

Had a gentle day as we were both pretty worn out by the work on the windows over the previous 5 days.

Still we have managed to fully clear the forward heads compartment including headliner. We have found 3 common types of backing. One is a black with netting. It pulls off really easily. Another is a foam that is quite orange and just crumbles into dust, any remaining bits can be vacuumed off the plywood. Finally there is a more yellow foam which is firmly glued to the plywood after the vinyl lining is removed. This is a pain to scrape off.

At least temporarily we have removed the multi way door to the forecabin (it could either close off the cabin or the toilet). It needed a piece of wood across the “entrance to the heads” that I kept banging my head on. We have also adjusted the sliding door so that it closes a bit easier. Again this is up for potential redesign.

We want to use the area for our 2nd Natures Head composting toilet, a wash basin, a holding tank, a shower and possibly there is space for a spin dryer (we plan a hand cranked washing machine but a powered spin dryer to minimise electricity use but also to keep drying clothes as easy as possible).

From the heads we switched to the ongoing task of clearing the cockpit locker. Again very pleased with the progress. We have at last got rid of all the remaining metal hot air heater hose and exhaust (it was in very poor condition and made a huge mess).

Then I tackled the wood container from the paraffin Jerry can. That meant I could get to the broken water pump and water filter. Then the big triumph after a lot more cutting we got to take out the old calorifier water heater. It was was still full of water but started leaking from seams as well as all the connections.

We setup a block and tackle giving Jane a 5:1 mechanical advantage to pull it up while I manipulated it past the obstacles.

Then as it was pouring with rain we just threw it over the side to sort out later.

We also got rid of the last hose used to extract air from the battery compartment and engine, ironically it was full of water.

We have also cut away most of the old battery cables (very convoluted and all different lengths and specifications).

So now we can see better possibilities.

We should be able to provide access to the pump thru hull valve from the galley.

We want to site water pump and hot water tank where they can be maintained. Not yet sure where but certainly clear of electrics like the alternator.

This means we can make a better space for our new batteries with shorter cables and leaving more useful space in the cockpit locker.

We finish off the day with well earned Fish and Chips 😊

Added comfort and luxury

So we now have some LED lights (mains only) in the aft cabin and the corridor/tunnel to it. Got them from Costco, 3 individual strips with one of them as the controller. Wave your hand in front of it to turn them on or off. Going to be very useful for boatyard winters, especially until we have got the 12 volt wiring installed.

Plus we also have our new infrared radiant heating panel installed. Just need to get some batteries for the wireless timer/thermostat. Time will tell if it is as efficient and effective as the very bold claims.

Heating panel has arrived

So our infrared radiant heating panel had arrived.

This is definitely an experiment. The size is the smallest available, calculated by wall space rather than how much heating is needed.

It will plug into a switched mains socket which is controlled by a wireless timer and thermostat.

So we don’t know whether it will keep our cabin at a comfortable temperature and we don’t know if the energy consumption will limit it to use when plugged in at the boatyard. But it does look cool 🤔

Project shopping

So I’ve been shopping. Hunting for cheapest options did mean several suppliers as I didn’t want to buy unbranded, low quality components in safety critical areas (such as 600A switches).

We now have most of the supplies for all the glassfibre work. Plus the majority of things to get the batteries, inverters, solar and 12v distribution installed.

Plenty of other things will be needed but this is enough to keep us busy for quite a while 😊

Bio-epoxy resin and hardener; glassfibre mat; pumps/trays/filler etc; lots of wire of different sizes, battery monitor, 12v distribution switch, circuit breakers for inverters, main battery switch; dielectric grease, glassfibre mat scissors.
metal for busbars, various crimp connectors for wiring, MC4 connectors for solar, nuts and bolts for building busbars
General purpose crimp tool (initially for solar MC4); big crimp tool for sizes 10mm2 to 120mm2

The Electric Plan: Wiring

We were very fortunate to have a lot of help at the weekend from our son who is halfway through an HND in electrical engineering. So we now have a wiring diagram and all the technical details worked out for the solar charging, batteries, through to the inverters and to the 12v circuit breakers.

The plan is to keep the engine starting and alternator charging almost entirely separate from the Lithium house battery bank. The only connection will be a battery to battery charger that can be manually turned on to top up the house battery bank if we are using the engine and it’s starter battery is fully charged. We do not want to plan to run the engine just to charge the batteries. Short term that means using less diesel and it means we don’t spend money upgrading the alternator (which would be pushed far too hard by the demands of directly charging the big lithium house battery bank). Long term that is because we want to end up with an electric motor anyway so money spent improving the engine charging ability is wasted.

This simplifies things. However, due to my decision to keep a 12v battery bank, for wide availability of appliances and to make it cheaper to expand battery bank capacity (you can add individual extra 12v batteries rather than needing multiples), makes the wiring more critical for safety and to avoid lots of inefficiency with the high current needed for big appliances (particularly the inverters [producing 240v AC] and the windlass).

So our batteries will be in two layers using the original battery box.

Bottom of the image is the original battery box with the space next to it on the right for the old paraffin fuel tank for the old hot air heating.

The engine starter battery will be at the bottom left of the picture. House battery 1 will run lengthwise to fill the rest of the bottom of the battery box. The other two house batteries will sit side by side on top of the first two (on a shelf, not directly on top). They will be set slightly aft of the lower battery so that it’s little lcd screen for it’s BMS (Battery Management System) will be visible (fortunately for us these big batteries have the terminals and LCD screen all at one end). Should we ever need it we could potentially add a 3rd layer of batteries (for a potential massive bank of 1,500AH), although this would reduce access to the rest of the cockpit locker).

One of the challenges will be lifting 38kg batteries down into the cockpit locker. So I’m going to sort out a “crane”, basically a block and tackle fastened to the wheelhouse above the locker. However, I’ll also need one to get the batteries from the ground onto the boat in the first place. I’m going to need to put my thinking cap on for that as the “normal” solution would be to use the main boom but the mast is currently down.

The space reclaimed from the paraffin fuel tank will be used for a +ve and a -ve busbar (following advice from Nigel Calder‘s book) for the house batteries. This allows the most even balancing of both load and charge for the batteries. We are over-sizing this busbar by using Stainless steel 30mm by 5mm bar and M10 bolts, all mounted into a wood frame with a transparent acrylic top to prevent shorting by tools etc falling on it, plus it keeps water off. After the -ve busbar everything on the load side goes through a “shunt”, this comes as part of a Victron battery and power monitoring system. It will give us a display of the battery condition as well as things such as total current power use, total power use etc.

We carefully priced all the big cables between the batteries and inverters (and windlass). It was 25% cheaper to buy the cable in reels, with connectors and tools than to buy them ready made. These are massive and are going to be a huge pain to bend when we are installing them. However, they are sized so that we have no worries about overloading them, even if we were to run both inverters at full power (that is 4,000 watts!) plus have the windlass running at the same time (12v 1,500 watts).

We are going to re-purpose the “wet locker”, the hanging space between the engine and the steps as an electrical supply cabinet. So on the load side two big cables for the -ve and two for the +ve will come to a big 600A on/off switch mounted under the steps down to the cabin so it is easily accessible. From the switch power goes to another pair of busbars to which all the big electrical stuff is connected: 2 x inverters (each with a circuit breaker); windlass circuit breaker; and two 12 volt distribution boards with circuit breakers.

“Wet locker” as it was when we bought Vida

That means we are going to be pretty much replacing all the 12v wiring in the boat. Given it is all over 40 years old we feel that isn’t surprising. It does mean we can move the switch board from over the galley which will create more space there. We were going to need new lighting cable anyway as there are so few lights in the cabins at the moment. It also means we can sort out the problems with the lack of a continuous earth at the same time.

Current 12v switch panel
Inside the existing 12v switch panel

The solar charge controllers (initially 3 Victron MPPT controllers) will also go in the “wet locker” and be directly connected to the main battery bank busbars again with overspecced wire for efficiency and safety. We can monitor and control these using bluetooth from our phones.

Whilst the wet locker is “round the corner” from the companionway so should be very protected from waves it does have an open front at the moment so we will make a canvas “curtain” to stop any water from ever getting in. It is the best place we can find for a combination of accessibility, weight distribution and closeness to the batteries. It should mean a total cable length between battery and inverter of under 5m. That would be acceptable with 70mm2 wire but we are using 95mm2 so we are well oversized.

As there won’t be an official wet locker anymore (not that it has been used for that in the recent past) we expect to use the forward heads compartment for our wet waterproofs where they can drain into the shower sump. If we have lots of guests it will just have to be only in dry weather 😉

Renewing the electrics is one of the bigger jobs we have to do so we are really pleased that we now have concrete plans and lots of the parts on order.

The Electric Plan: Solar

So in my last post on Introduction to generation I outlined the options and challenges for renewable energy generation and concluded that we were going to start with solar.

This video from Desiree and Jordan, Project Atticus, has been helpful. Like us they have a ketch (although smaller) which means a radar arch doesn’t work.

The simplest first step is going to be 4 x 40w solar panels on the top of our wheelhouse. It has a perspex “window” slot in the middle to allw you to see the mainsail when steering. That restricts things a bit but we can essentially fit one 40watt panel in each corner. Hopefully only one side at a time will be in shade from the boom & sail. So the panels will be connected in series along each side and then the two sides connected in parallel. That way the shaded side doesn’t affect the output of the other side. These will connect using a single Victron MPPT controller to the house battery bank.

The second step is to setup 4 large 175watt panels. They are approximately 1.5m long by 0.7m wide. We are starting with 2 controllers for these (one per side of the boat). The intention is to do some experimenting and end up with a variety of places they can be setup depending on whether we are at anchor or in a marina or sailing.


We are going to fit legs to the middle of the short sides. The bottom of the leg will be fixed just inside the edge of the boat. So the panel can be “stored” vertically or it can be swung out and the angle adjusted for maximum effect. They probably will need to tacked with the boat so that on the downwind side they don’t hit waves (ie we fold them away on the side we are heeling towards). At anchor they can be fully deployed and should get minimal shading. They will go from the back of the boat forward about 3m which should mean they are clear of where we get in and out of the dinghy as well as clear of sheets (the ropes that control the sails) when sailing. We probably won’t be able to use them when tied up in a marina as they will either overhang the dock where people walk or be in the way of other boats. We will make them reasonably quick for us to remove so that we can put them in other positions when that will be more effective.

Mizzen Boom

When we are anchored or in a marina they should fit across the boat while resting in the middle of their length on the mizzen boom. Not quite sure what will be the easiest way to fasten them here as the legs won’t be quite as long as the boom is high.

Stern Gantry

I haven’t quite given up on putting panels off the back of the boat. It would require a “goal post” that is clear of the swinging boom (and sufficiently braced). I’m thinking the panels would need to be able to slide either behind the boat (when using the mizzen) or forward (blocking the mizzen but out of the way for docking).

Wheelhouse Sides

I’m not sure if this can be made practical enough. I was wondering about fitting one long edge to the top side edge of the wheelhouse and then supporting the panel to stick out horizontally. They would not stick out much beyond the side of the boat but you would have to duck under them to walk forward and they might catch on ropes (particularly jib sheets).


The 4 x 40watt and 4 x 175watt panels we have at present should give us 860watts which is a good start, although we have to assume that due to shading we will be looking at more like 400watts effective at any particular time (depending on whether we move the big panels around when on anchor).

If tests show that all the places I’ve mentioned are possible then we might be able to get to over 1,500 watts which would be awesome (and enough to start considering an electric motor).

Beyond that if we can sort out storage when not in use we could potentially fit another 4 around the sides of the boat when at anchor.

By this time traditional conservative sailors are going to be horrified about what Vida will look like 🙂 To us though not needing fossil fuels is incredibly beautiful and very worthwhile.

To facilitate the flexibility we will end up with a variety of connection points around the boat supported by multiple MPPT boxes. Until then we will experiment using longer extension leads while we work out what works best.

One of the big challenges is that most of the examples (on YouTube that includes channels like Sailing Uma, Project Atticus, Beau and Brandy Sailing, Rigging Doctor) were at least started in the tropics where the experience of the sun is quite different to North Wales. We need more panels and we need to angle them more efficiently than they do.

We also need to focus a lot of attention on minimising the use. Having a large battery bank and big inverters needed for induction hob cooking could tempt us to be heavy electric users meaning we will never be able to generate enough renewable energy, I’ll be writing about that side of the equation too.