Electric motors on a Woods Flica 34' sailing catamaran

[mariobrothers88]

Hi guys, I am currently building a woods flica 34' sailing catamaran and I am planning out how to fit it out. I was thinking of installing an electric inboard engine (in particular, the EP-12 electric inboard by Elco motors: EP-12 Electric Inboard - Elco Motor Yachts https://www.elcomotoryachts.com/product/ep-12-electric-inboard/) on one hull and using an electric outboard engine (the EP-9.9 electric outboard by Elco motors: EP-9.9 Electric Outboard - Elco Motor Yachts https://www.elcomotoryachts.com/product/ep-9-9-electric-outboard/). I want to have 4x440watt solar panels (total of 1.76 kwatt) and a lithium ion battery bank. I don't want to use any diesel or gasoline for anything. I want to use an electric pressure cooker like the instant pot for all my cooking. What do you guys think of this plan? Are there any issues with using a single inboard and a single outboard that I'm not aware of? Also would I even need to install diesel or gas tanks since I will be relying solely on electric? I want to be able to do blue water cruising and be off grid/self-sufficient as possible. What do you guys think of having a small generator like the predator from Harbor freight or honda as well to make it a hybrid boat? I actually don't want to carry it as I don't think it will be necessary so I can save on weight/maintenance issues. Would that be foolish?

 

[fallguy]

Don't do it Ron!

The industry is not ready.

You will still want your solar for fridge and others, but cooking is super hard on supply; so I went propane cooker.

 

[mariobrothers88]

Hey Fallguy, I'm curious why you say this. What do you mean the industry is not ready? There are several sailing channels on youtube who have electric engines and they seem to be doing pretty good. Certainly lithium ion batteries are well proven and have significant advantages over lead-acid batteries. Are you saying the electric motor industry isn't ready? Or that there's not enough infrastructure to support electric boats? I want to keep my electricity use down to a minimum so most likely I won't have a fridge or air-con (I plan on canning my food). I like the electric pressure cookers because they are efficient in their cooking. I will also carry a propane cooker as backup as well. I appreciate any insights on this!

 

[fallguy]

The engine costs are too high.

The range of vessel on electric is too low. Sailboats need electricity when there is no wind. No wind and cloudy and you are dead in the water.

cost out the electric engines and batteries for 100 mile range or even 50 miles; pretty sure you need lotsa batteries

 

[mariobrothers88]

Thanks for the input! The elco electric outboard EP-9.9 goes for $2910 and the elco electric inboard goes for $7995, which isn't too bad. I would need a lot of batteries though, you are correct about that!

My plan is to do as much sailing as possible, I don't really plan to use the motors if I can sail. I like to have the inboard for hydrogeneration and the outboard would work for a dinghy as well. If I include a generator, then I can use diesel or gas as well.

I've heard sailors get pretty good amount of energy from solar panels even on cloudy days. But this is just from watching youtube videos and reading forums- any real world input would be greatly appreciated!

The engine costs are too high.

The range of vessel on electric is too low. Sailboats need electricity when there is no wind. No wind and cloudy and you are dead in the water.

cost out the electric engines and batteries for 100 mile range or even 50 miles; pretty sure you need lotsa batteries

 

[bajansailor]

Have a look at this article about Jimmy Cornell's latest venture - he is building an all electric Outremer catamaran for another round the world voyage at the age of 80.
Jimmy Cornell explains his electric multihull project: Zero-carbon cruiser http://nauticmag.com/2020/04/10/jimmy-cornell-explains-his-electric-multihull-project-zero-carbon-cruiser/

 

[Rumars]

All depends on your definition of "cruising". Having electric propulsion is only marginally better then going engineless, so all planning has to be done accordingly. If you are ok with this, then yes, electric is feasible. As for your motor choices, remember that the plans specify two 9-18hp diesels, and the EP-12 is a 6.8hp motor, while the EP-9.9 is a 6.3hp motor. With both running full bore you are barely above the minimum recommended power. But, as above, all depends where and how you want to "cruise".

For going hybrid there are better options then a small petrol generator. On a catamaran the most sensible option is "through the water", meaning you have two completely independent propulsions, one electric and one fossil fuel based. This could mean inboard diesel in one hull and inboard electric in the other, or two outboards, one gas, one electric, etc. Simply because you have an engine does not mean you need to use it all the time.

What does not make sense is you wanting to keep electricity use at a minimum and not having a fridge but having electric cooking. Regardless of what electric cooking system you use (induction plate, thermomixer, etc.) it will draw more in an hour then the fridge and freezer in a day. There is no reason whatsoever to not have it that is related to energy consumption. Aircon is a different thing, a boat with a serious enough battery capacity can have it, but recharghing the batteries can be a problem.
Anyway, you can try your chosen lifestyle beforehand, unplug the fridge, buy an electric pressure cooker, and switch off the aircon. By the time you finish the boat you will have a good ideea how you like it, just don't cheat by buying fresh chilled things every day unless you plan to cruise this way.

 

[fallguy]

Rumars answers far more eloquently, as usual.

The real problem with electric engine systemd is the run time. For a sailboat; you generally are only counting on them to get you in n out of ports. The amount of solar required is really high and battery higher still.

My boat will not use electric for heating or cooling or cooking. Consumption rates are too high. Refridgeration is the big one, and autopilot can use a lot at times.

For propulsion, an engine pulling 95 amps at 48V is going to take down a 200 amp hour bank really fast. So, you say, well, I'll go to 400 amp hours. Basically, that is 8 batteries or 240 pounds for two hours run time or maybe three; lotsa factors. But 240 pounds in equivalent fuel tanks and fuel is about 60 gallons! 60 gallons can run for days. And the batteries need to be accessible. That means placement somewhere for maintenance. Guess what. Fuel tanks go in bilges with either removable panels or access to senders or no access.

So, then you option for lifepo4 banks. Those are really expensive and for me; a cold climate nightmare.

Electric motors will be here, but they are super expensive for the return. The solar needs and the battery needs are very high. All drives cost.

 

[fallguy]

A lot of people forget battery bank life drops when you deep discharge; so just because you have a 100ah battery doesn't mean you want to discharge at that rate.

once you start an excel sheet and start seeing your consumption rates and discharge allowances and real needs; you are going to be very sad

Then if you are out at sea and need to get in, but have poor winds and it is night; your bank will deplete and you are stuck; perhaps in a storm's path. Did you read Richard Woods Eclipse sos call story?

If you want to spend the small fortune on electric; take Rumars advice and give yourself fuel on one hull

 

[alan craig]

I just had a very quick look at pressure cookers and they are rated at 1200 to 1500W - but I didn't find out how long they need to be on. I've had enough of lead batteries in my very small boat and am now looking at lithium options, I've discovered that used electric car batteries are now becoming readily available and are being reused in other vehicles, cell modules are also available and that's what I will probably use, not for crossing oceans though. Solar panels suffer from shading so keep them as far away from shade of sails etc. as possible. Split panels are now available; essentially two panels wired in parallel in one unit. When one half is partially shaded the other half can still produce full power.

 

[mariobrothers88]

I recently bought the instant pot duo crisp which is a combination air fryer and pressure cooker. It's a pretty amazing device that makes delicious food at the touch of a button I highly recommend it. It is 1500 watts and it takes about 20 minutes to cook so if you use it twice a day let's say conservatively it uses up 1500 Watt hours. The solar panels should generate enough energy to run the instant pot air fryer in an hour of sunlight if my math is correct (and please correct me if I'm wrong!). I would much prefer to use the instant pot air fryer combo than to use a fridge/freezer.

Yes I've heard of people using old tesla and electric car lithium batteries with success.

Per Rumars suggestion I might go with an electric inboard in one hull and a diesel outboard in the other hull. I really want the benefits of regen to have power while cruising but be able to motor during emergencies if there's no wind or sunlight.

 

[mariobrothers88]

Hi Rumars thanks for your fantastic input! According to the spec sheets on the website, the EP-12 electric inboard is 12hp and the EP-9.9 electric outboard is 9.9 hp. Where are you seeing that it's 6.8hp and 6.3 hp respectively?

I like your suggestion of having an electric inboard in one hull and a diesel outboard in the other hull. However

Also I plan to sail when there's wind and fish when there isn't so I'm ok with cruising that is marginally better than going engineless. Or read a good book while I wait for wind. I'm in no hurry.

If there's a storm coming, I would assume there would be good wind prior to the storm to allow me to sail out of the way of the storm? Or is that wishful thinking on my part?

All depends on your definition of "cruising". Having electric propulsion is only marginally better then going engineless, so all planning has to be done accordingly. If you are ok with this, then yes, electric is feasible. As for your motor choices, remember that the plans specify two 9-18hp diesels, and the EP-12 is a 6.8hp motor, while the EP-9.9 is a 6.3hp motor. With both running full bore you are barely above the minimum recommended power. But, as above, all depends where and how you want to "cruise".

For going hybrid there are better options then a small petrol generator. On a catamaran the most sensible option is "through the water", meaning you have two completely independent propulsions, one electric and one fossil fuel based. This could mean inboard diesel in one hull and inboard electric in the other, or two outboards, one gas, one electric, etc. Simply because you have an engine does not mean you need to use it all the time.

What does not make sense is you wanting to keep electricity use at a minimum and not having a fridge but having electric cooking. Regardless of what electric cooking system you use (induction plate, thermomixer, etc.) it will draw more in an hour then the fridge and freezer in a day. There is no reason whatsoever to not have it that is related to energy consumption. Aircon is a different thing, a boat with a serious enough battery capacity can have it, but recharghing the batteries can be a problem.
Anyway, you can try your chosen lifestyle beforehand, unplug the fridge, buy an electric pressure cooker, and switch off the aircon. By the time you finish the boat you will have a good ideea how you like it, just don't cheat by buying fresh chilled things every day unless you plan to cruise this way.

 

[mariobrothers88]

Thanks everyone for all the fantastic feedback!

Let's say, theoretically, I equipped the flica with an electric inboard in one hull, and a comparable diesel inboard (with alternator) in the other hull and I balanced the weight between the two hulls. I plan to carry enough diesel fuel to get me out of any sticky situation I might encounter on a long voyage. I feel like a lot of the potentially dangerous scenarios could be overcome with good seamanship, planning, and good sailing knowledge.

The best way to be safe is to strive for excellent seamanship. Which means being in the right ocean at the right time, reading weather forecasts, ability to heave-to and sailing knowledge in general, good route planning, and so much more.

Even with the best of seamanship, eventually you will encounter heavy weather. In which case, I would heave to. If I really need power, and the battery bank is depleted, I could use the diesel to motor.

Are there any other scenarios you guys can think of that would be potentially dangerous in a flica equipped with one inboard electric and one inboard diesel/alternator?

The diesel/alternator could also charge the lithium batteries during long stretches of cloudy days. And I wouldn't need a generator, which is a plus.

I also plan to put in a watermaker, most likely the seawater pro. I spoke with them and they said that they will soon be selling a 12V brushless high pressure pump motor within a few weeks, I think I will probably go with that.

I spoke to Elco motors directly and they said that all their inboards have regen. However, I couldn't find anything on the website about regen, which is surprising. I feel like if they really had regen, they would definitely put it on the website, so maybe the person I spoke to was a trainee or just didn't know. If you guys think this is fishy, I will definitely call again to confirm if they really have regen.

I'm thinking of steering with a monitor windvane as autopilot isntead of installing an electronic autopilot.

I want to be able to circumnavigate with this so I want to make sure I can handle any situation that might come my way. During the long stretches like the Pacific crossing, I do not plan to use the instant pot/air fryer, fridge/feezer, aircon, or anything really other than the essentials to save my power for the engines. I won't use the diesel engine at all except for emergencies, and will only use the electric engine if there's no wind but plenty of sunshine. I probably won't install aircon, but will probably install a small fridge/freezer, but won't use it during ocean crossings.

 

[Rumars]

Hi Rumars thanks for your fantastic input! According to the spec sheets on the website, the EP-12 electric inboard is 12hp and the EP-9.9 electric outboard is 9.9 hp. Where are you seeing that it's 6.8hp and 6.3 hp respectively?

Their own published technical specifications, it says there for the EP-12 "Kilowatts (continuous output kW rating) - 5.1 kW", and the EP-9.9 "INPUT POWER (WATTS) 4,704W". This is a marketing trick called " electric horses are bigger", but they are not, a Watt is a Watt regardless of generation source.
As for regen, yes both have it (as does any AC or PM motor) but they don't mention it because it's not important for their customers, wich are mostly inshore poweboaters. Regen is a function of fitted propeller and boat speed, and the result is not very predictable without actual testing. Anyway, before you spend big money on Elco you can also look at something like this Curtis 1236SE-5621 HPEVS AC-9 Brushless AC Motor Kit - 48 Volt, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits https://www.evwest.com/catalog/product_info.php?cPath=8&products_id=341&osCsid=4rfsf0m390jppqe86htn0nha02

You need to understand power consumption and generation: 1.76kW of solar will make you energy independent with fridge, freezer, watermaker, broiler and autopilot and have energy to spare. If we take 50% efficiency over 8 hours of sunlight we have a generation of 880W×8h= 7040Wh for the day. Stop thinking like a hermit, there is no need for it. Once the battery is full, power is free, you can't "save it for the engine" anyway. Your bigger problem will be how much battery you can afford to stuff all that free energy into.

Yes, you don't need a generator, there are 48V alternators available, up to 5kW. As for how much diesel to carry, that is personal preference. Just don't overload the boat, cats don't like that.

 

[gonzo]

It is possible if you have the funds. Realistically, the output of solar panels is about 30% of their rating. Large banks of Li Ion batteries can't simply be thrown together in a box. They need power management software and cooling to keep them from going up in flames. Mixing an inboard and an outboard can be done, but I see no reason why unless it is a proof of concept. Also, batteries and solar panels degrade. That fact should be taken into consideration as cost through the life of the system.