Arcona

[Fr J Hackett]

Wonder what the energy density of latest generation batteries is compared to diesel..
Presumably the electric version is a bit lighter hardware-wise so potential weight saving there?

The boat looks quite tender which I have put down to the removal of engine and other stuff. It is quite quick though for a 50 year old boat.

 

[lustyd]

Wonder what the energy density of latest generation batteries is compared to diesel..
Presumably the electric version is a bit lighter hardware-wise so potential weight saving there?

Very few people burn batteries, and even fewer get all the energy out of their diesel. This is a pointless comparison brought up by people who for some reason don't like electric power. Practical experience is completely different to this comparison since electricity will be replenished by sun, wind and sailing while diesel is a one and done event which is extremely inefficient. The theoretical energy density of diesel is completely irrelevant.

 

[lustyd]

The boat looks quite tender which I have put down to the removal of engine and other stuff. It is quite quick though for a 50 year old boat.

Are you suggesting they need to add 200KG of batteries?

 

[Fr J Hackett]

And if you pay attention they are trying out the genny to see what happens. They certainly didn't need to, and they changed their minds pretty quickly due to noise.

No they didn't need to at that point because they had about 50% left in their batteries but it wouldn't take long to deplete them and at below 5 knots they are int negative regeneration capacity and are going to have to start switching things off.

 

[Fr J Hackett]

Are you suggesting they need to add 200KG of batteries?

No just making a comment about the boat as it stands.

 

[lustyd]

But they could just have easily waited for wind, which did appear. They are thorough though and wanted to show what happened with the genny, which was good viewing.

 

[Yealm]

Very few people burn batteries, and even fewer get all the energy out of their diesel. This is a pointless comparison brought up by people who for some reason don't like electric power. Practical experience is completely different to this comparison since electricity will be replenished by sun, wind and sailing while diesel is a one and done event which is extremely inefficient. The theoretical energy density of diesel is completely irrelevant.

What an unimaginative post !
(and so incorrect - I LOVE the concept of electric power)

 

[BabaYaga]

The difference being that a diesel with an empty tank can't dock when it gets in (easily) whereas the electric yacht will potentially arrive with a full charge. Yes, both have to sail, but the electric never needs to explicitely refuel at the dock and so is unlimited range on the engine if used appropriately. Diesel power will never achieve this, while electric will gradually redecue the period where the motor can't be used.

Yes, unlimited range, provided that you have unlimited time.
(I'm sure there are some people that would travel in such a fashion, after all some well known cruisers have sailed very far with no engine at all. But I think they are too few to drive technological development).

 

[Laser310]

On the contrary, I would have thought the very limited range was the main obstacle for electric propulsion to take off?

I tend to agree

I think it would be okay for coastal cruising and weekending, as long as it is used intelligently.

but for offshore passages i think most people want several hundred miles, at least, of motoring ability in case of emergency. A mid 40ft boat can easily have over 500 miles motoring range.

 

[fredrussell]

Will a genny provide enough power to run an electric drive on its own, if the battery was flat? That would seem to be the answer if so - a sort of hybrid system. All this talk of just waiting while you’re battery recharges seems to ignore the fact that sailing is very often done to a strict timescale - ie tidal gates, minimum depth over river bars and the like. As long as the genny could run the boat’s electric motor I’d happily convert.

 

[lustyd]

Will a genny provide enough power to run an electric drive on its own, if the battery was flat? That would seem to be the answer if so - a sort of hybrid system. All this talk of just waiting while you’re battery recharges seems to ignore the fact that sailing is very often done to a strict timescale - ie tidal gates, minimum depth over river bars and the like. As long as the genny could run the boat’s electric motor I’d happily convert.

Yes, Uma showed that test. That said, it's mostly unnecessary even with current generation yachts which can easily motor for 6+ hours. Unless you're motoring all the way accross the channel then it wouldn't be necessary. If you're doing that on a regular enough basis for it to be an issue, then you're a motor boater and should probably not be buying an electric yacht in the first place

 

[[3889]]

But they could just have easily waited for wind, which did appear.

Like in the old days when sailing vessels had no auxiliary engine at all? Electric motors are a step up in convenience from that situation but diesel engines are a bigger step up from electric given current technology.

 

[lustyd]

Like in the old days when sailing vessels had no auxiliary engine at all? Electric motors are a step up in convenience from that situation but diesel engines are a bigger step up from electric given current technology.

Not sure what your point is. Nobody is disputing the convenience of motor boating, this discussion is about electric sailing yachts.

 

[rotrax]

Not sure what your point is. Nobody is disputing the convenience of motor boating, this discussion is about electric sailing yachts.

A nice thing to have, quiet, no engine and fuel smells and can be recharged from renewables.

But, we are a long way from being there at the moment.

The Chichester Harbour eco-tour electric catermaran is a case for examination. Roof full of solar, plugged in at night, still has a short range.

The vessel, Solar Heritage is a pensioned off Swiss ferry, so possibly old tech.

It is extremely quiet.

 

[flaming]

The modern marine Diesel has allowed cruising boat designers to get away with a lot... A lot of cruising boats in the last 30 years or so are completely hopeless at sailing in light winds. Partly due to the hull, but largely due to the rigs, which have been undersized and underspecced with hopeless bags as standard for a long time.

As a result of which people think that they need long cruising range under engine, because they are used to needing it when the wind is light. Which of course it often is in the Summer....

Swap the design philosophy to "This boat will make meaningful progress under sail in 5 knots of wind or more" and suddenly a range under power of say 5-6 hours of motoring seems completely reasonable for a coastal cruiser.

Also swap the mindset "I'm going to Weymouth this weekend" becomes, "Forecast is for light winds, stay local". I mean, I never really go that mindset anyway. No wind forecast all weekend, yet still people motor for 6 hours from the Solent to Weymouth, then motor back again on Sunday.... I'd far rather spend a few hours making a couple of miles up the Solent, then anchor up for lunch.

The reality is that internal combustion has not got a long term future. It might take 20 or 30 years or more for it to really disappear, but it will go.

People thought EVs weren't practical until Tesla showed it could be done, and could be done well. Clearly the sailing world needs its Tesla, pushing the tech, learning all the time and proving to the rest of the sailing world that it can be done. Arcona seemed to have picked up that challenge, good on them.

 

[Fr J Hackett]

The modern marine Diesel has allowed cruising boat designers to get away with a lot... A lot of cruising boats in the last 30 years or so are completely hopeless at sailing in light winds. Partly due to the hull, but largely due to the rigs, which have been undersized and underspecced with hopeless bags as standard for a long time.

As a result of which people think that they need long cruising range under engine, because they are used to needing it when the wind is light. Which of course it often is in the Summer....

Swap the design philosophy to "This boat will make meaningful progress under sail in 5 knots of wind or more" and suddenly a range under power of say 5-6 hours of motoring seems completely reasonable for a coastal cruiser.

Also swap the mindset "I'm going to Weymouth this weekend" becomes, "Forecast is for light winds, stay local". I mean, I never really go that mindset anyway. No wind forecast all weekend, yet still people motor for 6 hours from the Solent to Weymouth, then motor back again on Sunday.... I'd far rather spend a few hours making a couple of miles up the Solent, then anchor up for lunch.

The reality is that internal combustion has not got a long term future. It might take 20 or 30 years or more for it to really disappear, but it will go.

People thought EVs weren't practical until Tesla showed it could be done, and could be done well. Clearly the sailing world needs its Tesla, pushing the tech, learning all the time and proving to the rest of the sailing world that it can be done. Arcona seemed to have picked up that challenge, good on them.

I was impressed with the Pearsons sailing ability even if a little tender so I think you are right given a boat that can sail well in 5 or 6 knots then what they have is viable but as you say people would have to sail within the limitations and forget about time

 

[whaup]

Will a genny provide enough power to run an electric drive on its own, if the battery was flat? That would seem to be the answer if so - a sort of hybrid system. All this talk of just waiting while you’re battery recharges seems to ignore the fact that sailing is very often done to a strict timescale - ie tidal gates, minimum depth over river bars and the like. As long as the genny could run the boat’s electric motor I’d happily convert.

Beta hybrid?
Heat Exchanger Hybrid Propulsion - Marine Propulsion Engines Beta Marine

 

[flaming]

I was impressed with the Pearsons sailing ability even if a little tender so I think you are right given a boat that can sail well in 5 or 6 knots then what they have is viable but as you say people would have to sail within the limitations and forget about time

Not forget about time, just be more realistic about what is a good destination for a windless weekend.

 

[gregcope]

Uma does not have significant Solar (IMHO) compared to other yachts. Ie there are many yachts with much more solar of similar size. There is a Pogo 10.50 with Flexible panels on their statpack.

They did one you tube vid about making a wind generator (vertical one) but have gone quite in a while, I assume because they are in the far north where getting supplies for DIY is tricky.

If they wanted they could extend range by adding more Batteries and/or Solar generating capacity.

I would assume the same with Arcona who could add more Batteries and Solar panels. For example a Bimini and sprayhood with panels. Solar panels instead of cockpit dodgers. You could easily get to a 1kw of capacity.

Like Cars, Boats that are converted are often not optimised for the task. Ie a Tesla has more range and better performance than nearly any electric version of a thing. Same with a VW ID4. Same logic would apply to electric boats. Load them up with solar panels and LifePO4 cells from the buildstage.

 

[Fr J Hackett]

Uma does not have significant Solar (IMHO) compared to other yachts. Ie there are many yachts with much more solar of similar size. There is a Pogo 10.50 with Flexible panels on their statpack.

They did one you tube vid about making a wind generator (vertical one) but have gone quite in a while, I assume because they are in the far north where getting supplies for DIY is tricky.

If they wanted they could extend range by adding more Batteries and/or Solar generating capacity.

I would assume the same with Arcona who could add more Batteries and Solar panels. For example a Bimini and sprayhood with panels. Solar panels instead of cockpit dodgers. You could easily get to a 1kw of capacity.

Like Cars, Boats that are converted are often not optimised for the task. Ie a Tesla has more range and better performance than nearly any electric version of a thing. Same with a VW ID4. Same logic would apply to electric boats. Load them up with solar panels and LifePO4 cells from the buildstage.

Their solar panels are 480 watts which they say gave them 3 to 3.5 Kw a day in the Caribbean with a boat use of 2Kw. and a battery capacity of 15Kw
With their latest motor providing they stay in sunny places I don't think they have much problem but UK and north it's not going to work unless they sail for 8 to 10 hours a day at 6 knots or thereabouts as their regeneration at that speed was giving them 500 watts. Their solar panels will generate less than 1Kw probably a lot less.
Flexible panels are not that efficient so covering the boat with them still won't cut it for sailing in northern latitudes for a greater part of the year.