Twin Electric! Salona Yachts

[kof]

I think you would need very good regen to push back in the power needed to fill the batteries again. I know when I drive up a hill in my car for an hour, I will see a lot of power usage (gravity sucks!) but once I get to the top and start going downhill, regen kicks in and I actually start pushing power back into the car - BUT, and this is important - I never regen 100% of what I've used on the way up. Not even close (and I tried this on the Stelvio a couple of years ago). You have friction and heat losses that mean that regen is never 100%.

I also think that the hull design and weight impact electric a lot - a nice, slippery light and easily driven hull might work a lot better than a heavy displacement one (basic physics) so the choice of boat matters. You can't back off on revs once you reach your cruising speed or the water resistance will drop your speed very quickly (unlike a car). Having 2 regen props also means that you get the best possibility of good regen as one prop is always in the water flow.

It's an area I'm really interested in - not convinced yet and there are times I know electric regen would never have worked (low batteries and zero wind would mean no regen possible). Will be interesting to see how it improves over years but I'm not ready to jump in right now.

This is kind of the opposite of what the Uma guys are saying, and they have been pure electric for 5 years with full time live aboard and ocean passages. They say you need a marina if you have diesel since your batteries need a recharge after a day sail. And I agree - my solar helps keep my batteries full during the day but on my night passages the batteries get low. But with regen, your batteries are full at the end of every sail so no need to find a marina!
I'm trying to think what the longest continuous period I have run under motor and I guess in the last 6 years it's probably about 6 hours, but that was followed by 18 hours of high speed sailing.
At the moment the cost differential is probably discouraging volume builders from offering this. Kudos to Salona!

 

[dunedin]

This is kind of the opposite of what the Uma guys are saying, and they have been pure electric for 5 years with full time live aboard and ocean passages. They say you need a marina if you have diesel since your batteries need a recharge after a day sail. And I agree - my solar helps keep my batteries full during the day but on my night passages the batteries get low. But with regen, your batteries are full at the end of every sail so no need to find a marina!
I'm trying to think what the longest continuous period I have run under motor and I guess in the last 6 years it's probably about 6 hours, but that was followed by 18 hours of high speed sailing.
At the moment the cost differential is probably discouraging volume builders from offering this. Kudos to Salona!

I would like to see the maths underpinning these claims for Sailing Uma and “batteries recharged after every sail”, without use of shore power. It kind of depends on whether you are
(a) sailing for 24 hours at 7 knots or 7-8 hours at 4-5 knots
(b) solar powered by Caribbean / Med Sun or northern European
(c) power demands.
So look forward to seeing the maths.

Note that Jimmy Cornell’s latest high speed 46 foot cat with special sail drives and propellers optimised for regeneration, abandoned his Elcano voyage as even cross ocean he could not generate enough to run all the systems and batteries went flat.

In this topic, IMHO, without maths / figures there is generally more hype than reality.

PS. The maths (though generally not the economics) do now work for a car, for inland river craft, and for marina based day sailers, but not for most coastal cruising yachts unless hybrid.

PPS. I gather sailing Uma are on their second electric drive setup in this time, so presumably the first was not as successful as they claimed at the time

 

[Buck Turgidson]

This is kind of the opposite of what the Uma guys are saying, and they have been pure electric for 5 years with full time live aboard and ocean passages. They say you need a marina if you have diesel since your batteries need a recharge after a day sail. And I agree - my solar helps keep my batteries full during the day but on my night passages the batteries get low. But with regen, your batteries are full at the end of every sail so no need to find a marina!
I'm trying to think what the longest continuous period I have run under motor and I guess in the last 6 years it's probably about 6 hours, but that was followed by 18 hours of high speed sailing.
At the moment the cost differential is probably discouraging volume builders from offering this. Kudos to Salona!

I have a 30lt tank and 20lts jerry can. The longest I've been between marinas is 19 days or 1600nm. 120W of sola and 200Ah battery. My limiting factor was cigarettes.

 

[Ningaloo]

I think you would need very good regen to push back in the power needed to fill the batteries again. I know when I drive up a hill in my car for an hour, I will see a lot of power usage (gravity sucks!) but once I get to the top and start going downhill, regen kicks in and I actually start pushing power back into the car - BUT, and this is important - I never regen 100% of what I've used on the way up. Not even close (and I tried this on the Stelvio a couple of years ago). You have friction and heat losses that mean that regen is never 100%.

I also think that the hull design and weight impact electric a lot - a nice, slippery light and easily driven hull might work a lot better than a heavy displacement one (basic physics) so the choice of boat matters. You can't back off on revs once you reach your cruising speed or the water resistance will drop your speed very quickly (unlike a car). Having 2 regen props also means that you get the best possibility of good regen as one prop is always in the water flow.

It's an area I'm really interested in - not convinced yet and there are times I know electric regen would never have worked (low batteries and zero wind would mean no regen possible). Will be interesting to see how it improves over years but I'm not ready to jump in right now.

Watt&Sea quote 200W @6kts, 400W @8kts, so more than sufficient to keep up with the 10-12a draw on batteries when sailing, but as you say, it could take a while if you have depleted a battery bank of the size used in the featured yacht. I don't think you can equate a yacht with a car as the car always needs the engine other than coasting or braking. Most of the time a sailing boat will not be using any engine whatsoever and the regen will be working 100%. Weekend sailors might "sail" when there is no wind, but when I live aboard, I would not leave port without a reasonable chance of sailing (without motor) at least 75% of the passage.
Like you, for me this is "interesting". I may dabble with the ePropulsion EVO outboard, especially if that can recharge the house batteries, but for now my auxiliary remains diesel.

 

[Ningaloo]

PPS. I gather sailing Uma are on their second electric drive setup in this time, so presumably the first was not as successful as they claimed at the time

I think they are pretty genuine and really did start with a scrap boat and very little money. Their first "salvaged" electric motor did not have regen. They were gifted the OceanVolt by a "patron" who had fitted four into his cat and found that he only needed two.
I'd also be interested in the maths from Uma's solar and engine regen. I think they only fitted the OceanVolt last year (in Plymouth) and are currently in Norway, so certainly not able to rely on 12 hours of Mediterranean sunshine! For me the issue is how long it takes to recharge a heavily depleted battery after motoring and how to keep the batteries topped up on anchor with limited solar hours.

 

[lustyd]

I would like to see the maths underpinning these claims for Sailing Uma and “batteries recharged after every sail”, without use of shore power.

Uma have never claimed that for their own boat. For the boat being discussed they hit 2KW regen at 8kt sailing, and they have (I think) 15KWH bank so the maths is easy enough and suggests that after 10 hours you'd have a "full tank" again, or more likely 12-15 hours easy sailing. Remember that that's day or night, so unless you're becalmed for weeks it's probably more than sufficient alongside a smallish solar installation. Obviously no good for delivery trips or impatient sailors who start the donkey if the wind is below 10kt but certainly feasible that you'd generally arrive fully charged.

 

[Frogmogman]

Kudos to Salona!

Couldn't agree more. And Kudos to the customers who put their cash on the table.

Although this Salona is not the perfect answer to the problem, without builders dipping a toe in the water in this way, and early adopters getting on board, these systems will not develop and move forward.

In time, with the advances being made in battery technology (thanks to the car industry), and initiatives such as this, I'm sure we will see more evolved systems appearing quite quickly.

 

[dunedin]

Uma have never claimed that for their own boat. For the boat being discussed they hit 2KW regen at 8kt sailing, and they have (I think) 15KWH bank so the maths is easy enough and suggests that after 10 hours you'd have a "full tank" again, or more likely 12-15 hours easy sailing. Remember that that's day or night, so unless you're becalmed for weeks it's probably more than sufficient alongside a smallish solar installation. Obviously no good for delivery trips or impatient sailors who start the donkey if the wind is below 10kt but certainly feasible that you'd generally arrive fully charged.

I have again searched the Salona 46 info and not found the tech details of the installation. If anybody has a link to this please share.

A 15kWh battery sounds very low. That is equivalent to a diesel tank of just 5 litres nett. And with twin engines, depending on whether the OceanVolt 10kW or 15kW version, running twin engines the battery would last in theory between 30 and 45 minutes at full power. And that would be draining battery from 100% to 0%, which is unrealistic. So more likely 20-30 minutes at full power.

And full power could easily be needed on occasion. A modern 46 footer would typically have a 60-75hp diesel. Even 2x15kW drives is only 30kw, or around 40hp equivalent.

These calculations don’t equate with a claim of 3 hours range at 8.5 knots (which sounds like full chat for just 30kw engine power)
=> 3h x 30kW = 90kWh (which would be much bigger, heavier and costlier than a Tesla 3 battery pack, and take a very long time to recharge]

The claim of 10 hours at 6.5 knots (in a mirror calm) is consistent with the 3 hours at 8.5 knots, as reducing speed by 2 knots is indeed likely to increase range threefold. But again even if shut down one motor and ran the other at 2/3 power (ie just 10kW), that would be 100kWh. And can you really push a cruising 46 footer at 6.5knits with just 13hp?

So I must be missing something here, and hence would love to see a proper tech spec to review. Or got my maths very wrong, in which case please correct my maths.
PS. From the plans the Salona 46 seems to have a dedicated space for a generator. That makes sense

 

[lustyd]

Yes, you're missing a great many things. I have lost the motivation to try to explain them in this thread, and I suspect you'd still
play dumb even if they were explained. You quote posts explaining regen maths and then try to convert that to motor and power stats. Much of the spec is in the video and online, feel free to do the research if you have a genuine interest. Suffice to say that accelerating a heavy boat uses more power than maintaining velocity in one. You've made some figures up yourself there, the 8.5kt quoted was sailing and for regen of power, and nothing to do with motoring, although I imagine if pressed it might hit that speed motoring briefly. Diesel and electric have no equality so putting electric power in terms of litres of diesel is a waste of your time.
The range and speed of the boat aren't up for dispute, these boats are real and have been tested. You can do all the maths you want, but your conclusions are irrelevant against real world results.

 

[lustyd]

Sorry I just checked the video and it was 30KWH - I did say I was unsure

 

[dunedin]

Yes, you're missing a great many things. I have lost the motivation to try to explain them in this thread, and I suspect you'd still
play dumb even if they were explained. You quote posts explaining regen maths and then try to convert that to motor and power stats. Much of the spec is in the video and online, feel free to do the research if you have a genuine interest. Suffice to say that accelerating a heavy boat uses more power than maintaining velocity in one. You've made some figures up yourself there, the 8.5kt quoted was sailing and for regen of power, and nothing to do with motoring, although I imagine if pressed it might hit that speed motoring briefly. Diesel and electric have no equality so putting electric power in terms of litres of diesel is a waste of your time.
The range and speed of the boat aren't up for dispute, these boats are real and have been tested. You can do all the maths you want, but your conclusions are irrelevant against real world results.

I am not making up figures - from the Sail Croatia article .... “Salona 46 is fitted with an electric engine that has 10 hours of autonomy at the speed of 6.5 knots or a maximum speed of 8.5 knots and 3 hours of sailing.”
Think there are some language translation issues there, “sailing” meaning like a ship.
This was about propulsion, as the next sentence moves on to regeneration ... “When the ship sails, it generates electricity again, and from a completely empty battery to a fully charged one, it needs about 20 hours of sailing at a speed of five and a half, six knots”

Actually there is reasonable comparability measures available between diesel and electric. And the maths used works well comparing to things like the Spirit 44e boat test.

I see you have now posted a revised battery size of 30kWh (I won’t comment about making figures up yourself
Less out of the ballpark but still doesn’t seem to equate to the range and speed figures quoted.

 

[lustyd]

“Salona 46 is fitted with an electric engine that has 10 hours of autonomy at the speed of 6.5 knots or a maximum speed of 8.5 knots and 3 hours of sailing.”
“When the ship sails, it generates electricity again, and from a completely empty battery to a fully charged one, it needs about 20 hours of sailing at a speed of five and a half, six knots”

There we are then, you do have the numbers.

Actually there is reasonable comparability measures available between diesel and electric. And the maths used works well comparing to things like the Spirit 44e boat test.

And yet here you are seemingly suggesting the maths doesn't work. Perhaps you have a formula that worked once, but if it's not lining up with the numbers here then the maths evidently doesn't work. I have also never seen a method to generate diesel while sailing, so your determination to compare them like for like will never reflect reality. Diesel will always have a smaller range than any electric boat with regen or solar. Timescales for the range are a variable, but the fact that electric range is infinite is not under dispute. There is a question around whether a range of 80NM in one sitting is sufficient, sure, but that is a different question. Most of us would probably think 80NM is sufficient on a sailing yacht if we looked at real world usage rather than trying to bash a new solution.

I see you have now posted a revised battery size of 30kWh (I won’t comment about making figures up yourself
Less out of the ballpark but still doesn’t seem to equate to the range and speed figures quoted.

Yes, perhaps you missed the part where I said I wasn't sure, and then again said sorry that I had not been certain. You could have looked these things up yourself, of course, I was just trying to help you along

 

[dunedin]

There we are then, you do have the numbers.

And yet here you are seemingly suggesting the maths doesn't work. Perhaps you have a formula that worked once, but if it's not lining up with the numbers here then the maths evidently doesn't work. I have also never seen a method to generate diesel while sailing, so your determination to compare them like for like will never reflect reality. Diesel will always have a smaller range than any electric boat with regen or solar. Timescales for the range are a variable, but the fact that electric range is infinite is not under dispute. There is a question around whether a range of 80NM in one sitting is sufficient, sure, but that is a different question. Most of us would probably think 80NM is sufficient on a sailing yacht if we looked at real world usage rather than trying to bash a new solution.

My point was that the maths does work for other examples of electric propulsion, but don’t seem to add up in this case for the claims of the Salona 46 - but until we can get a proper technical spec and measured range and recharge in practice let’s leave there.

PS. The claimed range for the Salona looks to be between 25.5 and 60nm at the speeds quoted.

 

[lustyd]

I'd love to see some of this info for my Jeanneau, the reality is that there isn't a claimed range for my boat either. This isn't an exact science, my 150l tank will let me motor for somewhere between 35 and 100 hours with a range of between 0 and 1000NM depending how much diesel I use for other purposes, how fast I go, and the conditions. What I can say for certain, is that if I motor for 2000NM I will definitely have been back to land and filled the tank, whereas this boat could easily do 100,000 miles under motor without returning to land. There are pros and cons to both.

 

[Buck Turgidson]

The thing is you can circumnavigate without an engine. People have done all sorts with zero engine range. The video in question is a sales pitch. Uma are and have always been shills. I know many people like them and that's fine but the do come out with some nonsense sometimes and they are heavily sponsored and not always open about it. I don't mind. But they are not for me and this boats numbers don't add up on top of the fact the interior is straight from the vàsobéöüg collection in Ikea.

 

[lustyd]

At least they showed their testing on video. You’re just moaning about strangers on the Internet

 

[geem]

At least they showed their testing on video. You’re just moaning about strangers on the Internet

No, we are moaning about a terrible sales video that is presenting something as excellent that is blatantly far from it.

 

[Tranona]

I thought the video was great. It showed the capability of the boat in the type of use for which it was designed. I don't know how anybody who watched the video could get the impression that the boat was intended for bluewater liveaboard cruising. Or indeed why they should dismiss it because it does not meet that requirement. Perhaps it was that irritating Uma couple who contributed nothing except as useful deckhands when sailing.

This boat is designed for Med type holiday sailing, typically a couple of hours motoring and maybe 4/5 hours sailing in non tidal, conditions with winds in the range of 0-25 knots or so. Days start and finish in anchorages/marinas village quays 20-40 miles apart. Thinking back, exactly the way I used my boat in Greece for 10 years. As the Green man says a lot of places in the USA have similar conditions and sailing patterns.

To me the things that make this boat potentially work are first weight. It is less than 10 tons (comparable Bavarias, Hanses, Beneteaus etc are typically 12 tons+). This, together with the long waterline length, deep keel and big rig means it easily sails in the 6-8knots where regeneration starts to really come in. Not only is the design displacement low, but the boat does not need extra weight - no fuel, minimal stores clothing, possessions etc. Just 200l of water for the showers, few cases of beer and wine, some mineral water and enough salami, cheese, salad and bread for picnics for the 4-6 crew for a couple of days. A far cry from a bluewater boat of this size (HR Oyster etc), which will generally be 16 tons plus 3-4 tons of generator, fuel water stores, spares, tools, food personal possessions etc.

Second is the layout of large cockpit, drop down transom, open and airy interior with flexible accommodation. Personally I love the interior, perfect for its intended use. Of course no good if your image of sailing is being tucked up in a Scottish loch for the night, sitting at the chart table poring over charts, pilot books, cruising guides, tide tables and weather forecasts planning the next day of island and tidal race dodging and whether the forecast front will arrive before you get to your destination. A dram in hand, varnished teak woodwork, blue plush settees bathed in the warm glow of the cabin lights. complement the scene. Passage planning on the Salona will consist of a few minutes on the iPad looking at potential anchorages on Google Earth and maybe a quick phone call to the next marina or taverna to make a booking. Navigation is line of sight or more likely a waypoint on the large chart plotter at the helm. Who needs a fixed chart table or bookcase?

Third. Price. It is better to consider the price of the boat for what it is rather than the extra cost compared with a diesel version. Does the package meet the buyers' needs at a price they are prepared to pay? It seems to be about 10-15% more expensive than a similar size Bavaria (but about 40% of an HR 44!). Perhaps as already suggested this puts it in a price bracket where a charter operator might consider it. Clearly they need to have confidence in the reliability of the systems, and I suspect (like electric cars) the real world range may not be as good as claimed. But in the holiday sailing areas of the Adriatic, Greek Islands and Turkey where you are rarely more than 25 miles from a harbour the potential drawbacks are minimal.

I am encouraged by Ian's account of his electric Sadler. I was looking at how the Salona concept could be scaled down to a 10m boat and still be usable for UK coastal cruising. In fact Salona do list such a boat, but can't find any performance details. As he highlights the two major problems are high energy consumption once you get over 4 knots and poor regeneration, partly because unlike the 46 you have only one pod and a small boat like that cannot consistently sail at high enough speeds for regeneration. Go up a notch, though to a modern 10m like my Bavaria or similar from the other big builders, passage speeds of 5.5-6 knots under sail are common. Many coastal cruisers do less than 100 hours motoring a year, which for my boat equates to about 500 miles. But if you break this down into a typical days sailing is maybe 3 hours motor and 8-10 hours sailing - that is maybe 60-70 miles a day. So in theory well within the range of an electric boat with the larger capacity battery that Ian suggests, although a cross channel passage under motor alone would either be slow or give rise to buttock clenching over range! Bit like the good old days in my Eventide chugging along in the fumes of the Stuart Turner.. The fly in the ointment is that I motor at 5.5 knots and have plenty in reserve for adverse conditions, going against the tide, meeting a tidal gate etc. As Ian says you have to scale back your ambitions and make good use of tides etc as you are practically limited to 4 knots under power before "range anxiety" sets in.

If, however you could get a real 80 hour range at say 5 knots and good regeneration then it starts to make sense. If that can be done at a 10% premium over a diesel (£12-15 on a basic new 10m boat) then it may be a winner - not that many people in the UK are buying boats like that at the moment. Who will be the first to try?

 

[lustyd]

that irritating Uma couple who contributed nothing

A well thought out post and you make a lot of good points about the boat (although I don't agree that you couldn't go blue water in it if you wanted to). I do have to take issue with this statement though. Dan and Kika very likely wrote, filmed, diected and edited the whole piece - I found the video itself to be leagues ahead of anything the yachting press have done to date. Whether you like them or not, they are the reason nearly 300,000 people have watched the video and likely the reason many of us are even aware of the boat and technology*. Clearly they were paid for it, and they don't hide when they are doing things for commercial reasons, as shown in their latest video about a 48V windlass - now there's a dull subject!

*It's entirely feasible that YM have coverage of this yacht somewhere. Sadly their magazine isn't available in shops near me and their website has so many popups and ads I don't have the energy to get through to any content so appologies if I missed it, I did try.

 

[Tranona]

With regard to the video, apart from giving a guided tour of interior, showing where the wine is kept and that you can hide under the forward bunk (but no serious stuff on the technical side of the propulsion system), they added nothing to understanding what the boat was about that was not covered by the Green man. Of course much of the information he gave was in response to questions, but the questions were mostly obvious. A straightforward review by a proper yachting journalist could have conveyed the important information in half the time. The best bit about the format as I noted was sailing the boat in the way it was intended to be used, something that rarely happens in either review or advertising videos.

is a good example of what I mean.

Don't get me wrong. I appreciate their videos and understand why they are popular. They have done good practical things with their boat. Just that I find the style irritating and I think they were out of their comfort zone in promoting this boat. The market and expected usage is very different from what they know about, and even then they glossed over the only bit where they had common ground (the propulsion system). Also appreciate that the main audience was the US so the emphasis on the green and pure sailing dream was probably appropriate.

Of course the boat would cope with bluewater sailing but like using boats such as the Pogos you would have to keep it light and it would not be a comfortable ride. Just like performance catamarans the 3-4 tons cruising weight that a typical liveaboard cruiser adds to a boat of this size would kill the performance. Of course there are people who would travel light to take advantage of the extra speed, although in reality passage times (daily runs) in mixed conditions may not be significantly better than a more conventional medium displacement performance orientated cruiser of similar size - in fact an HR 44 would probably eat it for breakfast in passage making, although at roughly 3 times the price!

Don't think the boat has been reviewed in any UK mags, although Yachting World would be the obvious one. Problem with boat reviews now is that the UK market is almost dead for new boats and the mags are so short of money they can't afford proper journalists any more, nor the means to travel. Made worse in the past year of course by the restrictions.