Tacking a trimaran vs tacking a proa

[smallyachtsailr]

Hi all. I'm here to pick your brains. I have a small (tiny!) trimaran and am happy with it--it tacks easily and responds to the rudder well. I have no experience with proas. I'm working on a larger and faster lightweight trimaran (14' or so) design for car-topping. I often sail in narrow and sometime crowded waters, so I need a quick-tacking and maneuverable boat.

I'm considering a lot of different possible designs, although I'm focusing on another multihull. I've sailed hobies and was very underwhelmed by their tacking abilities. So catamarans are out. That leaves a trimaran, or a proa. To my mind, if I leave one ama off the trimaran and make it a proa I save a lot of weight and mass and beam--which means potentially a faster boat, and less to load on top of my car. But then as a proa, the one ama rarely leaves the water. A shunting proa simply doesn't look like a good idea in a narrow river or crowded anchorage (or am I wrong?). I have no experience and no idea how maneuverable a proa is in narrow waters. For example, I often have to tack between bridge abutments in a narrow river, against a tidal current. My small tri handles this easily, tacking only inches away from the concrete abutments.


Here's the question:

****All else being as equal as you can get it, which is more maneuverable, especially tacking, a trimaran, or a (tacking type) proa?****

Another way of phrasing it: Is the second ama worth it?

[Doug Lord]

I have no experience with proas either but Rob Denney is a member here and could enlighten you about proas and shunting etc.
Was the small trimaran you were considering going to be designed to fly the main hull?

[smallyachtsailr]

Thanks for the quick response Doug.

No, not a flying main hull. I'm also intrigued by the foil trimarans (Hydroptere!!!) but I have no experience with designing them--are the foils made of glass or steel? I'm going for an easy to sail lightweight tri (or proa?) that is faster than most boats its size, and also maneuverable. I've been designing solidly down the trimaran path, but have always wondered about proas and whether I could simply chop off one ama and some length off the crossbeams. Its tempting, but I'm afraid I'll lose too much responsiveness to the rudder. I've seen a couple proas in the area but haven't had the opportunity to try one.

[Doug Lord]

Originally Posted by smallyachtsailr

Thanks for the quick response Doug.

No, not a flying main hull. I'm also intrigued by the foil trimarans (Hydroptere!!!) but I have no experience with designing them--are the foils made of glass or steel? I'm going for an easy to sail lightweight tri (or proa?) that is faster than most boats its size, and also maneuverable. I've been designing solidly down the trimaran path, but have always wondered about proas and whether I could simply chop off one ama and some length off the crossbeams. Its tempting, but I'm afraid I'll lose too much responsiveness to the rudder. I've seen a couple proas in the area but haven't had the opportunity to try one.

======================
You should,without a doubt, sail one before you try to design one and that goes for the tri as well. Since you're not flying the main hull it seems like you wouldn't lose a whole lot(if any) performance to the proa configuration. Good Luck!

PS-Foils these days are made of carbon fiber/epoxy.

[gonzo]

Proas traditionally shunt not tack. The bow becomes the stern and viceversa.

[cavalier mk2]

I always doodle them so they shunt like a proa and tack like an outrigger for narrow channels or crowded waters.

[Corley]

On a very small boat like your proposing a tacking proa is easy to do just put a net on a rack on the side without a float like the production ninja pro shown in the following video. You sail the boat like an Atlantic proa on one tack and a Pacific proa on the other.

[Doug Lord]

Originally Posted by Corley

On a very small boat like your proposing a tacking proa is easy to do just put a net on a rack on the side without a float like the production ninja pro shown in the following video. You sail the boat like an Atlantic proa on one tack and a Pacific proa on the other.

======================

Corley, I saved the website for this boat and their trimaran but twice now when I clicked on it, it froze my computer! Good call to post the video...

[smallyachtsailr]

I do have trimaran experience--been sailing mine for--oh--ten years or more. Been in others occasionally too. Its proas that I'm not experienced with.

The ninja in the video Corley posted is very like what I had in mind if I didn't make a full trimaran, thanks much Corley.

Back to my question about proas--does anyone have experience with a tacking proa and know if the type of proa in the video tacks as well and easily as if it were a trimaran?

Either way I plan on smaller type amas that don't allow the main hull to fly--I don't want the weight and moment penalty of the larger amas and stronger xbeams--remember, as I said earlier I need good maneuverability. Of course speed is another issue--I'd guess the proa version might be a bit faster--higher SA/D.

Thanks for all the comments!

[cavalier mk2]

That is an outrigger in the video, not a proa. check out the Malibu outrigger pages for comparisons. a true proa is double ended and travels in both directions.

[Corley]

There is an article on proafile about the ninja pro they also consider it an outrigger from the purist angle. Interestingly enough the original render included a bruce foil (not included in the final design).

http://proafile.com/archive/article/238

[smallyachtsailr]

I appreciate all the advice. I can understand calling the ninja an outrigger rather than true proa. Nomenclature is often a problem--it has always bugged me that every double-paddle boat under the sun is referred to as a kayak although they vary widely in purpose and design.

In the ninja video it certainly looks like it can move in light wind, but he sure took his time coming about, even for such light wind. I will have to think about a roller-furling genoa, except that I do wish to keep things very lightweight and simple. I prefer a double-sheeted jib--it can even be big enough for some overlap. I know I do not want a heavy boat with a lot of unnecessary gear--in my mind better to go simpler and lose any weight I can--perhaps my penguin background speaking.

So many choices. I'll have to decide in the next month or two if I want to start building this winter.

[oldsailor7]

"Another way of phrasing it: Is the second ama worth it?"

Perhaps I am opinionated, but IMHO the answer is YES.

Tri's rule. Yay.

[cavalier mk2]

I heard some of the Brits came up to Newick a few years after Cheers took 3rd in the OSTAR and told him that he'd put one over on them because they'd been trying and nobody had been successful since.
I think they have a place though. They certainly are interesting in how many variations there can be just in the rig, leeway, steering basics.

[HASYB]

I always found the the plans of Chris White's Dragonfly very appealing, don't know if he still sells them though cause they're not at his website anymore.
http://www.chriswhitedesigns.com/