How feasible is 100% renewable electric cruising right now?

[StuM]

Originally Posted by Jim Cate

Really, this seeming problem is easily resolved by simply teleporting the vessel to some location where the sun is still shining brightly.

Similar degree of functionality...

Jim

But they didn't claim 28 hours continuous. Just a total of 28 hours, so if you sit on the stationary boat all night and don't use any energy for anything other than propulsion during the trip, you can cover that 168 miles in just a few days

[john61ct]

Yes that's designed for purpose!

Not suited for liveaboard cruising, and wouldn't want to be far from shore in a big blow

[GrowleyMonster]

Originally Posted by john61ct

Yes that's designed for purpose!

Not suited for liveaboard cruising, and wouldn't want to be far from shore in a big blow

True. Every boat design is an exercise in compromise. This one is all about solar electric power and speed. Accomodations (none) and seaworthiness (wellllll.....) took the back seat. Almost a proof of concept rather than a practical vessel but enough people believe in the concept that it sells. The economics are such that for a very narrow market, it makes financial sense to buy. The data from this boat is not really relevant to cruising. Electrocruising is a thing yeah, but no way you would ever approach the performance of this neat little solar electric motorcat with a boat that realistically could be used for ocean cruising. Lower your target speed to three knots and things start looking a little different. Expect 8 knots sustained and you gotta give up a lot. Too much, in fact.

Currently in the planning and model building stages, me and GF are looking at building a solar electric sampan for liveaboard bayou , ICW, lake, bay, and river cruising along the northern gulf coast region. Our target cruise speed? 3kts. Voice of experience talking. The numbers just don't add up for higher sustained speeds than that without excessive use of fossil fuels. If you just can't stomach going slow, solarelectric without significant use of generator is not for you. As for me, whenever I am on my boat I am already at my destination, so no hurrying, here.

Oh, and I will have oars. And GF is big and strong.

[Jim Cate]

Oh, and I will have oars. And GF is big and strong.

If you carry a big drum and a whip, perhaps you can up that target speed to 4 nots!

Jim

[valhalla360]

Originally Posted by stevegerber

To see a real world example of a renewable energy solar powered boat google the SoelCat 12. It's not a sailboat, it's a stand alone solar charged battery electric catamaran, but it seems like an interesting example of what is required in terms of solar panel wattage and surface area required, battery size and motor size to drive a boat. 8.6 kWp solar panels, 120 kWh battery storage, (2) 30kW electric motors. They claim it can go 6 hours at 8 knots on batteries alone. Pricing starts at $600K USD.

Of course, on a sailboat you don't have to motor all the time so a much smaller system could still be useful. But if you do want to have the option of motoring for many hours using only renewable energy you can see from this example that it does take a lot of panels which take up a lot of square footage.

Possible but with some major drawbacks:
- 2 x30kw motors means at full power with full batteries, you have around a 2hr range. (slightly more with the sun out but not a lot).
- At 39' with extremely narrow hulls, 8kts is probably possible for 6hrs as hull speed is likely around 12-15kts for such a narrow beam boat. Of course that's under perfect conditions, calm water and no headwinds. Fighting a 20kt headwind punching thru 6' waves, don't count on anything close to that range at 8kts.
- At 39' with extremely narrow hulls, the accommodations provided are closer to what you would find on a 30' cat, so you are giving up a massive amount of living space.
- $600k is about double what a similar 39' cat would run. If you compare it to a 30' cat it's 3-4 times as much.

I will give them credit, they didn't spec a pair of 5kw motors and claim magic HP. They did give it enough HP for tough conditions (of course, better not need it for long).

There are a few of these type of boats out there but they all run into the same issues. You can do it better and cheaper by just combining sail and diesel.

[stevegerber]

GrowleyMonster, thank you very much for posting! It's quite helpful to hear the real world experiences from someone who has built his own functioning electric propulsion system and what the practical limits and compromises are.

[Steadman Uhlich]

Originally Posted by valhalla360

I know most on this forum are coastal or ocean sailors but one option where it could be viable is canal cruising.

When we did the Eire canal, even in the worst weather, the canal was typically calm and at least somewhat protected from the wind and there aren't too many places where you are more than 5 miles from a place to tie up. Often speeds are limited anyway, so no great loss losing a little speed. Going thru locks, a burst of thrust is handy but rarely more than a few seconds at a time, so battery power isn't a big issue.

On the Eire, a lot of the town docks did have electricity and on a dedicated boat, you could install quite a bit of solar as long as you tie up away from shade.

I agree with your main point. An electric motor could be ideal for a canal boat, as they could "sail" on smooth canal water and plug in at marinas along the way.

Here is a link to a boat I saw today, that looks like it is designed for protected water cruising (e.g. Canals in Europe and bays). Designed and built in the Netherlands, of steel, it has two large electric motors (and diesel genset or hybrid). 64' long and relatively expensive, but fitted out as a motor yacht that is "electric."

http://www.cruisersforum.com/forums/...ml#post2603569

[stevegerber]

Interesting idea regarding electric canal cruising. A quick search on YouTube turned up the Thames Solar Electric canal boat.

[roland stockham]

On a cruising boat I think we are not their yet, mainly because of the cost of the batt bank.
But I am seriously looking at a solar powered dink with inboard electric motor. As long as you are OK with displacement speeds that looks entirely feasible. Big benefits are no gas to store and go off, no outboard to nick, instant start, lower maintenance costs and you don't finish up with the stern buried because of the weight of the motor and driver. A fixed solar panel would charge it with facility to plug in when needed.

[GrowleyMonster]

Originally Posted by roland stockham

On a cruising boat I think we are not their yet, mainly because of the cost of the batt bank.
But I am seriously looking at a solar powered dink with inboard electric motor. As long as you are OK with displacement speeds that looks entirely feasible. Big benefits are no gas to store and go off, no outboard to nick, instant start, lower maintenance costs and you don't finish up with the stern buried because of the weight of the motor and driver. A fixed solar panel would charge it with facility to plug in when needed.

Yes, depending on your intended usage and operating conditions, and allowable weight and cost, an electric dinghy is an extremely practical concept, even for non-engineer, "unbelievers". Plenty of folks already do this, with a trolling motor and a suitably sized deep cycle bank. This is actually cheaper than buying a gas outboard.

[RaymondR]

From a practicality viewpoint.

How does one achieve the flexibility of the liquid fuel systems where range extension is merely a matter of a couple of cheap jerry cans of fuel on the side deck with an electric drive system?

[StuM]

Originally Posted by Steadman Uhlich

I agree with your main point. An electric motor could be ideal for a canal boat, as they could "sail" on smooth canal water and plug in at marinas along the way.

Here is a link to a boat I saw today, that looks like it is designed for protected water cruising (e.g. Canals in Europe and bays). Designed and built in the Netherlands, of steel, it has two large electric motors (and diesel genset or hybrid). 64' long and relatively expensive, but fitted out as a motor yacht that is "electric."

http://www.cruisersforum.com/forums/...ml#post2603569

5500 litre fuel tank and 100HP/75KW . I doubt that the word "renewable" features anywhere .

[john61ct]

Well with electric propulsion, at least you're ready for the alternatives when they're more cost-effective.

[seandepagnier]

Originally Posted by RaymondR

From a practicality viewpoint.

How does one achieve the flexibility of the liquid fuel systems where range extension is merely a matter of a couple of cheap jerry cans of fuel on the side deck with an electric drive system?

How does one achieve the convenience of solar charging, and a cheap tow generator under sail, where visiting fuel docks is not needed with a fuel drive system?

[GrowleyMonster]

Originally Posted by RaymondR

From a practicality viewpoint.

How does one achieve the flexibility of the liquid fuel systems where range extension is merely a matter of a couple of cheap jerry cans of fuel on the side deck with an electric drive system?

Simple. With a parallel hybrid system featuring solar and shore power charging, and if a large fast sailboat, regen. Then you actually exceed the flexibility of the straight diesel propulsion system.

Electric is NOT for everyone. But it is nothing to sneer at, either. For some folks it is the ideal system. Me, I hate the sound and smell of an ICE. Some folks don't mind a bit. I hate having a minimum idle speed. Most folks don't know any other way. I distrust something that USUALLY starts and generally wants to warm up before use. When you don't know that there is a better way, it's just fine. The range of those jerry cans is cool but the range in a suit of sails is a bit better than that. It's all about who you are and how you do and how you want to interact with the universe around you, and what irritates you the most.