Originally Posted by Johncobb
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.
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.