Sodium ion batteries

Yes, but this is the same between diesel and electric. Eventually sailors run out of wind.

You’re confusing unlimited range with perpetual running. Most boats move once a week and could easily recharge in between. My point though is that if a diesel and an electric motor into the pacific, the diesel may never be seen again because it’s range is definitely finite and a fuel refill depends entirely on others. The electric may take time but will refill and motor without outside help forever effectively (and the components will last longer with no maintenance too).

The only issue is most sailors are in a hurry due to work. That doesn’t alter the fact that solar electric has infinite range while diesel does not.
Typical range of a yacht under electric propulsion is between 20 and 50 miles, OK at a pinch for a long weekend coastal but could be a considerable handicap offshore unless you are in one of the worlds windier places when you don't need a motor anyway which is the essence of a sailing yacht.
 
When you need speed to make a tidal gate of you are heading back to your home port after two weeks summer holiday and their is no wind, speed and range become important. Being able to manage 1kt under motor because you have no battery power available isn't offering anywhere near the convenience of a tank of diesel.
It makes far more sense to keep the diesel and ditch the gas in my experience. Our solar has harvested 1.1MW of power since July last year. We still have 4/5th of the tank of diesel we left La Gomera with in November last year.
As ever, it's about matching the technology to the requirements.

We met an all electric Ovni last year who had covered far more miles than us in their season. Very impressive boat. Most of their mileage was ocean crossing where there are no tide gates.

I would go all electric for a boat doing an Atlantic circuit, but I might not for a weekend cruiser in home waters where I had to be back at work on Monday morning.
 
LiFePO4 is a sort of grey rock - to make a battery out of it, it's smashed in to tiny pieces and coated in something like carbon nano-tubes to make it conductive.

As for Sodium - LiFePO4 took about 25 years to corner the market from the first batteries being made in the mid 90s. Sodium battery prototypes have some interesting properties, not least the wider temperature range over which they operate and the fact sodium is far easier to get than lithium.
 
As ever, it's about matching the technology to the requirements.

We met an all electric Ovni last year who had covered far more miles than us in their season. Very impressive boat. Most of their mileage was ocean crossing where there are no tide gates.

I would go all electric for a boat doing an Atlantic circuit, but I might not for a weekend cruiser in home waters where I had to be back at work on Monday morning.
Crossing the pond from east to west would not be such an issue in an electric drive boat. A friend has just done this in a Contessa 32.
However, the trip back can be a mixed bag of weather. I would definitely want diesel power for that leg. Its nice to be able to motor for 24 hrs if you need to avoid a coming storm or hook into some new wind that you would otherwise miss with very limited range.
There is a skippered TradeWinds charter cat here that is electric drive. It also has a diesel generator onboard because the solar can't keep up. They run that generator a lot. Its also really noisy. They really haven't achieved anything with electric drives.
 
I think that storage batteries are a mature technology and electric motors are incredibly efficient....solar is the hole in the chain....a sail material that could effectively harvest sunlight would make everything viable
 
I think that storage batteries are a mature technology and electric motors are incredibly efficient....solar is the hole in the chain....a sail material that could effectively harvest sunlight would make everything viable
Innefficient actually unless they are Brushless - then you have a much better form.

I have storage battery of 7Kw in my house based on the 13Kw solar system. I cannot imagine having that storage on-board ...
 
Innefficient actually unless they are Brushless - then you have a much better form.

I have storage battery of 7Kw in my house based on the 13Kw solar system. I cannot imagine having that storage on-board ...
I think that yachties worldwide are going to have to come to the same painful admission.....they need a catamaran
 
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Innefficient actually unless they are Brushless - then you have a much better form.

I have storage battery of 7Kw in my house based on the 13Kw solar system. I cannot imagine having that storage on-board ...
We have 14kw of storage on the boat. Its kept charged by 1300w of solar in the tropics. Now we are getting towards summer we have an excess of solar power. I have to keep thinking of stuff to use electricity for🤔
It already makes all our hot water, all our fresh water from RO, all our cooking, run our ice machine fridges and freezers.
This are all relatively minor loads that are easily met by about 5 or 6kWh per day. It can't reproduce the kW needed to drive the boat for 10 of hours at a time thst we very occasionally need
 
My 30ft boat has tankage for about 150 miles at 5 knots or so. Electric boats I’ve read about often seem to have a range of 60 miles of so. When that ‘typical range’ for a given weight of batteries raises to 100 or more, and it surely will soon, I wouldn’t hesitate to go electric. I have an electric outboard- it is pure joy to use after the many IC outboards I’ve had over the years.
It is well over 100 miles if you want it to be but that still misses the point that only electric can regenerate when you run out. Electric range is not what the battery manages, range is how far you can go before going to port. Electric is unlimited.
 
Being able to manage 1kt under motor because you have no battery power available isn't offering anywhere near the convenience of a tank of diesel
Oh remind me again how fast a diesel goes when the tank is empty? Reread my post. Electric with solar has infinite range.
 
Typical range of a yacht under electric propulsion is between 20 and 50 miles, OK at a pinch for a long weekend coastal but could be a considerable handicap offshore unless you are in one of the worlds windier places when you don't need a motor anyway which is the essence of a sailing yacht.
Absolutely wrong. Range is the distance you can go between ports and with solar that’s infinite. If you have a time related issue that’s different.
 
This are all relatively minor loads that are easily met by about 5 or 6kWh per day. It can't reproduce the kW needed to drive the boat for 10 of hours at a time thst we very occasionally need
That’s time pressure, not range. A self filling tank has infinite range. If you’re in a hurry then a product with lower range but faster execution is a good option. The diesel absolutely has lower range though.
 
Absolutely wrong. Range is the distance you can go between ports and with solar that’s infinite. If you have a time related issue that’s different.
I would say the range is what you could achieve with whatever batteries you have without charging just as the range of a diesel engined yacht is whatever it can achieve with a full tank of diesel which is how boats are described.
 
That’s time pressure, not range. A self filling tank has infinite range. If you’re in a hurry then a product with lower range but faster execution is a good option. The diesel absolutely has lower range though.
You do have a point but it is an argument against not for as with a typical 48V 40kW hybrid motor with somewhere between 500 and 1kW solar array that's going to take quite a while to put enough in the batteries especially if you don't want to ruin them by continually depleting them to zero charge. Food and water would become more of an issue.
It's why all the boats that are touted as having such propulsion have popping great generators and big diesel tanks.
 
I would say the range is what you could achieve with whatever batteries you have without charging just as the range of a diesel engined yacht is whatever it can achieve with a full tank of diesel which is how boats are described.
Really? Even if you could gather more fuel as you go? Seems like a definition used to prevent progress rather than describing how far the power system could propel the vessel?
 
I would say the range is what you could achieve with whatever batteries you have without charging just as the range of a diesel engined yacht is whatever it can achieve with a full tank of diesel which is how boats are described.

Absolutely agree.

It does not matter what charging regime you have .. from a plug and cable or a solar array ..... range is the distance you can travel on a single 'tank / battery setup' .....

Agreed that you can recharge batterys by solar ... but how long will it take ... and no fun if drifting about ....

If you have a 'diesel' engine - you intentionally limit distances needed to available fuel on board allowing a margin for safety.
 
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