lustyd
Well-known member
I think they said 1KWh in 24 hours for Svalbard which seems pretty good given the latitude
Arcona
- Thread starter lustyd
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gregcope
Well-known member
I would use semi-flexible in most areas which are more efficient. However I get your point on northern latitudes.
lustyd
Well-known member
I love it when people say flex panels aren't efficient, it very quickly and easily shows they have not used any in recent times so can be safely ignored.
Fr J Hackett
Well-known member
Quite correct the last time I fitted any solar panels to a boat was about 10 years ago and for sure things have moved on but can we say that even today they are not as efficient as rigid ones.
In terms of permanent location the boom / stackpack is neither a good place to site them in terms of efficiency nor is it a mechanically good place. On top of a spray hood reasonable but again reduced efficiency down to location, coachroof better than most in terms of efficiency but not good ergonomically even though you are supposed to be able to walk on some but panels need air circulation to work efficiently so again not ideal or close to it. Mounting on the guard rails again poor in terms of efficiency and a pain in the arse in terms of boat management and would continually be covered in salt. Nothing really beats a pair of high efficiency rigid panels mounted on a suitable gantry at the stern, if you have the space to store something then a semi flexible that can be moved around the boat when at anchor will add a little but the idea of plastering every available surface with a flexible panel is a non starter on so many levels.
Uma has 450 watts of panels that generated up to 3.5KW in the Caribbean they don't need any more and whatever they did in terms of more wouldn't get them into positive load over daily use in northern hemisphere for the greater part of the year.
gregcope
Well-known member
My sample size of one; Max output from a sprayhood panel for a few hours a day with the boom to oneside. Also rigid dodger mounted ones raised to horizontal (when possible) also work really well at max output.
Agree rigid on a gandry is a really good option.
Agree rigid on a gandry is a really good option.
AngusMcDoon
Well-known member
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Stemar
Well-known member
Let's face it, we've all been spoiled by reliable diesels, Go back to when most of us were kids or a bit before, and lots of boats didn't have engines, or had petrol jobs that could be relied upon not to start when you really, really needed them. Those that had diesels were mostly woefully underpowered, so couldn't drag you off a dangerous lee shore on their own. The folk who were sailing then would have loved to have a setup like Uma's - what? a fridge on a yacht!!! Power that just gets on with it? Wow!
To my mind, it's a different kind of sailing from going out for the weekend and, between reliable forecasts and powerful engines with several hours endurance, being pretty sure you can get the boat home and be at work on Monday morning. Not better, not worse, just different. It'll suit some people, not others. Good luck to both types.
To my mind, it's a different kind of sailing from going out for the weekend and, between reliable forecasts and powerful engines with several hours endurance, being pretty sure you can get the boat home and be at work on Monday morning. Not better, not worse, just different. It'll suit some people, not others. Good luck to both types.
Laser310
Well-known member
Many sailboat owners - particularly liveaboards - would be very unhappy with the compromises to space and comfort required for a boat that can sail well in wind of 5kts.
Sure - many of these boats look underpowered to me.., but that doesn't mean it's okay to build the same boat with a bigger rig - the boat may well lack the stability for a bigger rig without adding draft.., and with a bigger rig all the hardware needs to be upgraded - you end up with a much more expensive boat
In reality to get a boat with equivalent volume, but sails better, it will need to be longer and this also make sit more expensive.
Most of these owners would end up being power boat owners, rather than performance sailboat owners
Sure - many of these boats look underpowered to me.., but that doesn't mean it's okay to build the same boat with a bigger rig - the boat may well lack the stability for a bigger rig without adding draft.., and with a bigger rig all the hardware needs to be upgraded - you end up with a much more expensive boat
In reality to get a boat with equivalent volume, but sails better, it will need to be longer and this also make sit more expensive.
Most of these owners would end up being power boat owners, rather than performance sailboat owners
Frogmogman
Well-known member
Fair enough, but to go back to the original post, it was the Arcona 415 we were talking about, and that does have this sort of sailing performance.
DJE
Well-known member
From the article in the link "The standard motor is a 15kW Oceanvolt unit that gives equivalent thrust to a 50hp diesel." Last time I looked 15kW was about 20hp so how does that work?
dunedin
Well-known member
Yes, that is a question I hope one of the boat tests will put to Arcona - or better to a bollard pull test. It seems like PR bluff.
Of course a 40 foot boat rarely needs all 50hp, and an electric 15kW drive will be more efficient at low speeds. But on the rare occasions when full power is needed, in a gale to get off a lee shore for example, it would be a bit late to find out the PR was false.
lustyd
Well-known member
Very likely the same reason a Tesla beats the pants off a McLaren. Electric motors have the same torque all the way through their range while the diesel only puts out maximum power in specific conditions, which most likely are not the ones you're using most of the time. The motor unit fitted is demonstrably capable of driving the boat so what does it matter? These arguments about numbers are pointless distractions just as they were on cars.
Fr J Hackett
Well-known member
McLarens aren't oil burners. It helps if you get the basics right.
lustyd
Well-known member
I'm quite certain you knew what I meant, which means you're purposefully being obtuse for some reason.
DJE
Well-known member
Electric motors produce maximum torque at zero speed. As the speed increases they generate a back emf that reduces the current and therefore the torque. Diesels produce maximum power at speed but by careful selection of prop size and gear ratio that speed will be achieved at the maximum boat speed in the conditions for which the engine is optimised. It matters because Arcona are claiming some form of equivalence (in terms of thrust whatever that means) between a 15kW motor and a 50hp engine. This is likely to be misleading to potential customers.
lustyd
Well-known member
It does all appear to be explained on the Oceanvolt site so perhaps have a read of that first before claiming it's fraud?
Laser310
Well-known member
I think it's a great technology for daysailers
I have a 30ft boat that I daysail - it is a relatively high performance boat and is fun to sail in under 5kts of wind.
On a typical outing, I probably only run the diesel saildrive (13hp) for 5min on the way out, and 5 min on the way back
I am on a mooring, and can pick up the mooring under sail if needed.
An Oceanvolt system would be great for that boat
On the other hand, Oceanvolt says that their entry system for the Arcona 415 has only 25nm motor-only range at 5kts.
This is simply not enough for me.
Yes - I could double the battery bank and have 50nm - still not enough motor-only range for me in a 40ft cruising boat.
I have a 30ft boat that I daysail - it is a relatively high performance boat and is fun to sail in under 5kts of wind.
On a typical outing, I probably only run the diesel saildrive (13hp) for 5min on the way out, and 5 min on the way back
I am on a mooring, and can pick up the mooring under sail if needed.
An Oceanvolt system would be great for that boat
On the other hand, Oceanvolt says that their entry system for the Arcona 415 has only 25nm motor-only range at 5kts.
This is simply not enough for me.
Yes - I could double the battery bank and have 50nm - still not enough motor-only range for me in a 40ft cruising boat.
lustyd
Well-known member
if you're using 25 on the way out and then sailing, you'd double it with regen anyway for the way home assuming you're out for the day. That's one of the huge attractions, solar and regen will continually top up your battery so while you're right that it suits day sailors, it also suits liveaboard cruisers. The people in the middle will have to wait, but I'm certain when diesel hits £30/litre in a few years the moaning will reduce and they'll find a way to make it work ?
Kerenza
Member
could someone explain regeneration returns please?
AIUI a heavy displacement boat propelled at hull speed by the wind has a reasonable amount of excess power available. A lightweight craft at 3knts will suffer a high drag effect from the loaded propellor, in excess of the difference between a folding and fixed prop for instance.
Wouldn't this spoil the sailing most of the time?
AIUI a heavy displacement boat propelled at hull speed by the wind has a reasonable amount of excess power available. A lightweight craft at 3knts will suffer a high drag effect from the loaded propellor, in excess of the difference between a folding and fixed prop for instance.
Wouldn't this spoil the sailing most of the time?