Lagoon 420 hybrid + modern tech

[PacificGreen]

Originally Posted by valhalla360

Of course not, that's why it is exceedingly rare to find engineless sailboats.

Most will only start the engine when finally they are barely moving or in fact use it to motor sail when the winds are light.

Originally Posted by valhalla360

Odd, the standard calculation suggests a bit over 7kts and cats usually beat the standard calculation due to the narrow beam/length ratio. But if we accept your value, your suggested cruise speed of 4kts is still far below 80% of hull speed. Your average cruising boat with BELOW average size fuel tank can run at 80-90% of hull speed for at least 8-10hrs and most can do 24hrs or more.

Well my standard calculation and experience tells me my hull speed is 6.7 knots max unless I'm going to be surfing down waves. I have nice load carrying hulls. The standard calculation for mono is what I have to use. You can use whatever numbers you like to fit wherever you want your math to end up. I'm telling you I can cruise at 4 knots or higher comfortably if you look at the tracks I provided you would understand that. Really an average cruising boat is pretty vague with a below average tank is also very vague but running them at 80-90% on an average 100gallon tank well that is $200-400 gone. How far will your boat travel on a tank of fuel?

Originally Posted by valhalla360

Check the title of the thread. It's about a Lagoon 420, so if we want to extrapolate from your experience we need to scale it up. As far as your speculation regarding the "world renowned" Sun21, if it was so easy, why didn't they do it? This wasn't so long ago that the technology wasn't available. There has been no huge technological leap forward to suggest a different outcome.

In the case of the OP:

What if this system was revisited using Tesla batteries, folding props (giving up regenerative capability for efficient sailing), and modern high power solar (to make up for a lack of regenerative prop spin)? It would seem to me that the weight would come weigh down (lower battery weight and one less engine) and modern solar would provide far more "passive" charging without a sacrifice of speed while reducing generator load to reduce gas consumption. Thoughts?

Tesla batteries are the last thing you want to use on a boat unless you intend to run the entire tesla bank, cooling system and bms. Others have done it though with fractional packs:

https://www.youtube.com/watch?v=BRqcp4Tzzrg&t=0s

and

https://www.youtube.com/watch?v=my0T...ature=youtu.be

The solar aspect needs to be kept light and lots of it. A proper sized lithium battery bank is important - that is the key. Big cells at 48 volts. Think 400ah to 1000ah cells and 16 in series but suffice to say two 400ah 20kwh banks one in each hull would be fine for a 40kwh total. Speed will always be the sacrifice in exchange for unlimited range. Go with 2 small generators DC only. Originally it came with a 72v system. Just stick with 48v. Two 20kwh banks. Loose the mast and sail gear and mount your solar panels as light as possible. Stick with 10kw motors a side. I see room on that cat for 4000-6000 watts of solar. Loose that big honking diesel genset too. Ridiculous. If your solar boat doesn't move at 100amps 50amps a side at your sweet spot 4-5 knots you have problems. Run two strings of solar into each bank and enjoy. 1 run 2160 12 panels 79.6voc 32.88amps into one bank. That is like being plugged into a wall socket at home for part of the day. My panel mounting is low windage, light but not efficient. On a cat like a lagoon 420 the sky would be the limit. Cover that topside leave walkways and bow access.

So far as speculating why the Sun 21 didn't use thin solar or lithium batteries well probably just to prove it could be done with lead acid. Perhaps it wasn't in the budget as well. Design and planning started in 2004 and perhaps they were just lead heads anyhow.

Originally Posted by valhalla360

Huh? They were trying for the record speed for a crossing? If they could gotten anywhere close to a 9kt average speed, we'd be seeing a market shift replacing sailboats with solar powered boats because they can match or exceed sailboats and sun is more reliable than wind (fyi: their hull speed is probably closer to 12-15kts given the long narrow hulls)

They were not trying for a speed record crossing. Again simply because a solar boat can go 9knots does not mean they will all the time. In a crossing case they would certainly calculate that power expenditure. Also with an electric boat one should not get there hopes up as to top hull speed so better to calculate as a mono hull. Power to get there is counter intuitive to the operator and design. As it is they did quite well at 5-6knots average on old technology.

Originally Posted by valhalla360

What dingy has fridges, water heaters, toilets, washing machines etc..? I was pointing out an alternate use for the technology that is viable and for certain users, may even be cost effective. For pretty close to the price of a 2-4hp outboard (as most won't plane anyway), I could put together the solar powered system. There would be a convenience factor in that most users (how many really go back and forth 6-10times a day) would never need to worry about fuel and maintenance would be negligible. You just get in, throttle forward and go.

Okay I see your analogy now. The real alternative use for those boats with nice hull shapes and are elegant in the water would be to loose the ice engines and the sails and go solar electric. That is if one can be happy in the 1-10 knot range. One of the most discouraging aspects of my project is that now I paired my tender with a 9.9 Yamaha and well if it isn't one thing it is another. Can't beat electric for the simplicity once you get over the learning curve and adapt to the slow life.

Originally Posted by valhalla360

Sure you can cruise a very long TIME if you don't want to cover a lot of DISTANCE. Set the engine so it's just barely moving and you get a long duration. Bass boats with trolling motors do this all the time. They just need a little thrust to maneuver the boat but when they want to get 5-10miles back to the dock, they crank up the big engine.

I'll rephrase: Sure you can cruise a very long time almost unlimited if you do not want to cover a lot of distance FAST. Still 4knots times 24 hours is still 96 miles a day. I would agree and I'm guilty at times with my electric boat I have so much battery power it's ridiculous but yes low and slow. In my case if I have to make the tide I just put the throttles down and take the extra 2 knots. In one of my tracks and videos you can see me doing that racing back to beat a low tide or I'm out all night.

[valhalla360]

Originally Posted by PacificGreen

Most will only start the engine when finally they are barely moving or in fact use it to motor sail when the winds are light.

Define barely moving? It's a range with purist sailors willing to drift at 2-3 kts but from my experience, it's probably around 4-5kts for most coastal cruisers before they will crank up the engine and then they take it up to 5-8kts. Your 4kt cruise is the bottom barely tolerable speed under sail and they expect more under power.

Well my standard calculation and experience tells me my hull speed is 6.7 knots max unless I'm going to be surfing down waves. I have nice load carrying hulls. The standard calculation for mono is what I have to use. You can use whatever numbers you like to fit wherever you want your math to end up. I'm telling you I can cruise at 4 knots or higher comfortably if you look at the tracks I provided you would understand that. Really an average cruising boat is pretty vague with a below average tank is also very vague but running them at 80-90% on an average 100gallon tank well that is $200-400 gone. How far will your boat travel on a tank of fuel?

True there is no "average cruising boat" but 25' is clearly below average size for more than weekending. A 100gallon tank will allow most 30-40' boats to run at 6kts for 3-5 days continuously.

With a tank half that size, I can maintain 6kts for a couple days straight and it's well below $200 for a full fill up (I think your numbers are a few years old)

Sure you can cruise faster but for drastically shorter distances. If I cut back to 4kts, I can run continuously for around 4 days as with most cruisers actually trying to get from one place to another, it's a trade off we aren't willing to make. I already switched from a 25kt boat to a 5-7kt boat for fuel savings. There isn't a lot of cost savings to slowing down more but there is a big cost in convenience doing so.

They were not trying for a speed record crossing. Again simply because a solar boat can go 9knots does not mean they will all the time. In a crossing case they would certainly calculate that power expenditure. Also with an electric boat one should not get there hopes up as to top hull speed so better to calculate as a mono hull. Power to get there is counter intuitive to the operator and design. As it is they did quite well at 5-6knots average on old technology.

So they intentionally did a slow crossing (compared to similar design sailboats) when they could have done 9kts? This is like the Tesla drag race videos you see. It can accelerate very quickly but if you do that your range drops like a rock.

If the technology is there and typical cruisers will accept 4kt cruise speed, we should be seeing lots of manufacturers switching over and sales of the systems sky rocketing. Other than one off boats and a few startups that haven't put in more than a couple dozen installations, I just haven't seen it. Do you know anyone who's been in the business for more than 5 years and have say a few hundred installed?

I haven't seen anyone point out a company/system that has even a modest number of installed units and most that have been installed have been ripped out as cruisers found the limitations to restrictive. Unless all these developer are just idiots, it's not the developer...it's the technology.

[BigBeakie]

"Other than one off boats and a few startups that haven't put in more than a couple dozen installations, I just haven't seen it. Do you know anyone who's been in the business for more than 5 years and have say a few hundred installed?

I haven't seen anyone point out a company/system that has even a modest number of installed units and most that have been installed have been ripped out as cruisers found the limitations to restrictive."

I see Valhalla is still in denial. You are nothing if not reliable

As you have been told before, but have obviously conveniently forgotten due to your severe case of confirmation bias, OceanVolt meet all your criteria. Been in business since 2004 (16 years ago), first system installed 2006 (10 years ago) and to date have installed over 200 systems. And none of them have been "ripped out" let alone "most of them.."

So what do you know, you are wrong on all counts.

[valhalla360]

Originally Posted by BigBeakie

"Other than one off boats and a few startups that haven't put in more than a couple dozen installations, I just haven't seen it. Do you know anyone who's been in the business for more than 5 years and have say a few hundred installed?

I haven't seen anyone point out a company/system that has even a modest number of installed units and most that have been installed have been ripped out as cruisers found the limitations to restrictive."

I see Valhalla is still in denial. You are nothing if not reliable

As you have been told before, but have obviously conveniently forgotten due to your severe case of confirmation bias, OceanVolt meet all your criteria. Been in business since 2004 (16 years ago), first system installed 2006 (10 years ago) and to date have installed over 200 systems. And none of them have been "ripped out" let alone "most of them.."

So what do you know, you are wrong on all counts.

A whole 200 systems in 16yrs. Way to not break the "couple hundred" standard by not even 1 extra boat. That's what 12.5 systems per year?

There are approximately 12 Million recreational boats in the USA of which around 5% or 600,000 are greater than 26'. (cruising size)

OceanVolt has cornered approximately, 0.03% of the cruising boat market, if you ignore international numbers. Drastically less when you consider the smaller boats that presumably could benefit from this zero downside technology.

So who else is matching OceanVolt's numbers? Anyone?

[Vander Woestijn]

The arguments here keeps pointing to solar as an alternative and doing away with sails entirely. Correct me if I am wrong, but this thread was originally a discussion about a hybrid Lagoon sailboat, and not a hybrid motor boat.

Sailing is irreplaceable to me, not just because it’s the most eco viable propulsion system out there todate. But also because of the social aspects; sharing the sailing experience with family and friends is the best part of the yachting.

Solar cells still have a long way to improve. The power produced from a standard panel is OK when idle; topup house and appliance batteries. But forget getting any decent performance from any panel while underway.. even rigging shadows across any panel dramatically reduces its capacity.. by half or more!