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Old 23-01-2022, 02:11   #31
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Re: Catamaran with 6 masts, is it possible?

Also take a look at yrvind.com, he's an interesting guy who builds tiny boats with multiple tiny masts. They are incredibly slow and cramped but he doesn't care, he's not in a hurry. By making them small and slow the forces involved are tiny so they are indestructible.

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Old 26-01-2022, 08:58   #32
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Re: Catamaran with 6 masts, is it possible?

Thank you Eric for clear explanation. And thanks to others for comments.

So, I think that the best option will be most probably same unstayed masts and wing sails as on Energy Observer "Oceanwings" - concept by VPLP. Since they are computer controlled and fully automated they do not require much effort from the crew. I read also that they are more efficient.



Next idea:

I would like to add hydrofoils to make foiling cruising catamaran.

I know that my cruising catamaran is not going to be as light as racing one like those participating in America's Cup. My question is what speed I would have to achieve to get enough lift to glide / foil on the surfers of the water? And what type of hydrofoils I would have to install?

Thanks in advance for any constructive comments.
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Old 26-01-2022, 20:17   #33
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Re: Catamaran with 6 masts, is it possible?

Quote:
Originally Posted by Johncobb View Post
Thank you Eric for clear explanation. And thanks to others for comments.

So, I think that the best option will be most probably same unstayed masts and wing sails as on Energy Observer "Oceanwings" - concept by VPLP. Since they are computer controlled and fully automated they do not require much effort from the crew. I read also that they are more efficient.



Next idea:

I would like to add hydrofoils to make foiling cruising catamaran.

I know that my cruising catamaran is not going to be as light as racing one like those participating in America's Cup. My question is what speed I would have to achieve to get enough lift to glide / foil on the surfers of the water? And what type of hydrofoils I would have to install?

Thanks in advance for any constructive comments.
Hi John, Glad I was able to help.

As for your next idea, I doubt seriously that you would be able to make a blue water catamaran sail reliably on foils. The America's Cup boats were very light for what they were and they sailed on flat water where there happened to be decent wind. There are very few times that you have flat water out in the ocean, and when you do, there is little to no wind, so you won't have the power to propell the boat up on foils.

Also, blue water boats have to carry a lot of "stuff," which is generally pretty heavy when all is said and done. To lift heavy stuff out of the water by foiling forward motion, particularly at cruising speeds, you would need large area foils. These foils would work only a fraction of the time, and so otherwise they'll be sitting in the water collecting nasty growth--grass and barnacles--that will impede the ability to lift. It would be a constant struggle and chore to keep them clean. And, if the foils are working only a fraction of the time, that means that at normal cruising speeds you are simply dragging a lot of hardware through the water, which would be a lot of drag that would keep you from achieving normal cruising speeds as if you did not have the foils. Of course, making the foils retractable adds complexity and cost--is the time you ultimately spend foiling (if you can actually foil) worth the trouble and the expense?

In addition, foils necessarily need active control to keep them working moment to moment, so you would need enough crew on board to handle that, or a pretty sophisticated computer control system and heavy-duty actuators to operate them for you.

So, in my opinion, foils on a cruising catamaran is not a good idea--wasted money and effort. If you talk to some good multihull designers, I'm sure they'll tell you the same thing.

Cheers, I hope that's more worthwhile insight.

Eric
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Old 26-01-2022, 21:18   #34
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Re: Catamaran with 6 masts, is it possible?

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Originally Posted by chris14679 View Post
Also take a look at yrvind.com, he's an interesting guy who builds tiny boats with multiple tiny masts. They are incredibly slow and cramped but he doesn't care, he's not in a hurry. By making them small and slow the forces involved are tiny so they are indestructible.

If I was going to muck about with random sail arrangements, I would go with an A-frame mast with a crab claw sail.

Forces are low, easily reefed and the A-frame is only about half the height of a normal mast making it easy to pass under most bridges. Properly hinged, the mast could be dropped to the deck in seconds.

Here's a small example of the idea but it can be scaled up.
Shell Boats Crab Claw Cat
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Old 29-01-2022, 06:13   #35
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Re: Catamaran with 6 masts, is it possible?

Hi Eric.
Thanks again for your explanation.

So foiling cruising catamaran is out of the question?

What about those projects?

1. Eagle class-53 foiling cruiser inspired by Americas Cup
Link: https://www.yachtingworld.com/extrao...cas-cup-122594
2. Project for foiling cruising catamaran
Link: https://www.kickstarter.com/projects...8/foiling-cats
3. G4 foiling catamaran
Link: https://dnaperformancesailing.com/ou...ing-catamaran/
4. Another article about foils:
Link: https://www.cruisingworld.com/story/...for-sailboats/
Best regards - John
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Old 29-01-2022, 06:57   #36
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Re: Catamaran with 6 masts, is it possible?

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Originally Posted by Johncobb View Post
Hi Eric.
Thanks again for your explanation.

So foiling cruising catamaran is out of the question?

What about those projects?

1. Eagle class-53 foiling cruiser inspired by Americas Cup
Link: https://www.yachtingworld.com/extrao...cas-cup-122594
2. Project for foiling cruising catamaran
Link: https://www.kickstarter.com/projects...8/foiling-cats
3. G4 foiling catamaran
Link: https://dnaperformancesailing.com/ou...ing-catamaran/
4. Another article about foils:
Link: https://www.cruisingworld.com/story/...for-sailboats/
Best regards - John
You are so black and white with your thinking. Nothing is impossible. All boats are a compromise. In the case of the Eagle 53 the compromise is going to be higher maintenance and the fact that to make it light enough it has a pricetag of $9M.

There is a reason though for the trends in sailing vessels.
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Old 29-01-2022, 18:48   #37
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Re: Catamaran with 6 masts, is it possible?

Quote:
Originally Posted by Johncobb View Post
Hi Eric.
Thanks again for your explanation.

So foiling cruising catamaran is out of the question?

What about those projects?

1. Eagle class-53 foiling cruiser inspired by Americas Cup
Link: https://www.yachtingworld.com/extrao...cas-cup-122594
2. Project for foiling cruising catamaran
Link: https://www.kickstarter.com/projects...8/foiling-cats
3. G4 foiling catamaran
Link: https://dnaperformancesailing.com/ou...ing-catamaran/
4. Another article about foils:
Link: https://www.cruisingworld.com/story/...for-sailboats/
Best regards - John
Hi John,
Thanks for the links to the various foiling catamaran stories. I never said it could not be done, but I did surmize that it would be costly and perhaps impractical to the minds of most cruising sailors. Knowing what I do about the cruising life and the boats and their owners that we meet out here, I'll stand by my outlook, for the time being.

Reading between the lines, the articles variously talk about the necessity of light weight, software control, attentive crew of sufficient number to control the boat, the threat of impacts, etc., all of which are definite practicalities for the cruising sailor. The articles all emphasize the importance of light weight, and they talk mostly about structural weight, which is not too hard to achieve. But none of them mention anything about payload weight and what impact that may have on foiling performance. We all know, actually: heavy weight detracts from foiling performance. One thing that cruising sailors all do is pack on a lot of payload weight to sustain themselves for long, blue-water passages. So the cruising foiling sailor will have to be diligent to keep his payload weight low in order to achieve foiling performance. Can you do that reliably on a "blue-water cruising boat." Maybe, it will take rigorous planning and attention to detail while outfitting and provisioning.

Which is not to say, don't do it. By all means, if you are inspired and can afford such a boat, go ahead. I am sure we all have more to learn about how such boats can be built and sailed. Certainly the articles you have provided show a good start. I am just pointing out the most important aspects that are the roadblocks for a fully reliable, foiling, blue-water, passagemaking catamaran.

Cheers, and thanks again for the articles.

Eric
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