I have been playing with this monoproa for little more than two weeks now and i´m very impressed by its performance.
Its not multihull-fast, but i seriously doubt that any comparable mono could keep up with it. Its very stable and i have not found any unwanted or strange behavior in any kind of sea or wind. The low aspect schooner rig and lack of chinerunner takes its toll on upwind performance, but that is easy to change if one wants to. It does 50 degrees upwind which is pretty impressive given the weight, low aspect rig and total lack of any extra lateral resistance except the hull itself.
I think its important to see the monoproa more as a multihull than a mono, to get the performance and behavior one wants. It needs to be really slender to keep wave-making resistance low. It kinds of pops into and out of multihull-mode depending on the angle of heeling. My next model will have a slightly more slender windward side and a little deeper rocker to even it out a little. Its not a big problem, but one can not make the windward side to full. Even if it dips the sails into the water once in a while it does not heel over any more than that. There seems to be a sharp knee in the righting force at 45 - 55 degrees. Its very hard (for a 10 pound 4 feet model) to push it over more than 45 degrees.

Im so impressed that i (probably) will abandon my advanced sharpie proa. The monoproa has 70+ % of the speed, but is much easier to build and find a harbor that will accept it. I estimate that a 40 feet monoproa will be able to sustain 10 - 12 knots in favorable winds. Its a rough estimate based on the theoretical hullspeed and what i have seen it do when i sail it.

I hope i have some energy tomorrow, so i can build a revised monoproa.

Johannes.

I have been thinking some more about weight-distribution and dominant side on the monoproa.
I believe the monoproa should be thought about like a normal proa, where only one Australian guy wants to place weight to windward. Some 4000 years of extended proa-sailing points to weight to lee, and that is how i want it. It makes so much sense in so many ways.
Same with a monoproa. If i place the weight farther towards the wind the monoproa starts behaving strange. There seems to be some forces fighting when the monoproa sails over the waves. It will not keep its course and it moves much more jerky and unbalanced.

When i move the weight towards the line between the stems (much further to lee) the monoproa starts sailing much easier through the waves. The jerkiness subsides and it tracks very straight. Its important that it leans a couple of degrees to lee even when it is stationary.

This might be a little counterintuitive at first, but i think its quite logic and simple. Its the same behavior as a normal two-hulled proa. To much weight to windward will make a very unbalanced and strange behaving proa. I think one should have a the possibility to have some water-ballast to windward. One might have to ad some righting force when sailing hard upwind in strong winds.

I post a simple sketch of my thoughts. I used it to explain this to my girlfriend.

Johannes.

Have you come across TriloBoats?  The most efficient low cost live-on board boat I have seen.
In many ways the other end of the spectrum from a multihull,  though in some ways similar, in that they use initial stablity rather than balast.
Performance wise, read the blogs, the example in Alaska has survived some pretty ferocious conditions.

It did strike me that they may work well, or better in mono-proa form.

Mark

Im so impressed that i (probably) will abandon my advanced sharpie proa.

Gasp!!! I’m not sure if we can allow you to remain a member of Proafile in good standing. Just kidding… it’s been very interesting participating in your thought processes.

I apologize for not being very present over the past month - some family issues have kept me preoccupied.

I apologize for not being very present over the past month - some family issues have kept me preoccupied.

I hope everything goes well with the family! Family is much more important than Proas.

it’s been very interesting participating in your thought processes.

Thanks! I try to post as much of my thoughts and ideas as possible. I strongly believe in an open source like development. There is so much knowledge around here and i´m very grateful for everything i have learned from this site and forum. Everything i do is based on what i have read and seen on this site. I´m only trying to develop a cruising proa that will suit our needs, and i´m not afraid to test new ideas. Its a really fun learning process, and i hope readers of this forum will get something from all this. Only if we share our failures and successes - can we learn from each other.

With kind regards.
Johannes

Have you come across TriloBoats?  The most efficient low cost live-on board boat I have seen.

Yes Triloboats are very efficient and nice live-onboard/cruising boats. I have been following Triloboats since they started their blog. I have been thinking a lot of a bluewater-capable version of Triloboats. I have drawn a lot of Proa-variations to. I want to build a model to test their sailing abilities, but i don’t have the health and strength to build every model i would want to try.  I dont think the Triloboat is a good platform for monoproa experiments.They are supposed to be cheap and very simple. A monoproa is a 70% multihull and 30% monohull crossbreed. I’m just starting to investigate the concept. I´m very interested in what they can do.

I hope they will post some more interesting stuff on their blog soon. Its been to long without any updates.

Johannes.

Yesterday i tried to sail my Paradox and my monoproa sido by side to be able to compare them. It did not go well. My Paradox wanted to head up into the wind and my monoproa wanted to head down from the wind. I managed to sail them 3 feet side by side before they parted ways and i had to run after my Paradox. The Paradox had to much sail so it overpowered the rudder. I can´t reef the sail and there was to much wind.

I will try again soon. The water is very cold this time of the year. It soon going to be covered with ice. My feet hurt really bad after about 10 minutes.

I noticed something interesting with my monoproa. Even though it it was leaning so much it partly flooded with water, it always stopped at about 50 degrees. It never leaned any more than that. There seems to be a very high righting force after 40 degrees healing. If i try to heel it the other way it has a higher righting force at small angles, but once it heels over 30 degrees it almost vanishes.

Johannes.

The monoproa’s stability characteristics are very interesting. Were the sails or spars touching the water? If the spars are buoyant (wood?) they will help resist turtling. I don’t understand why there is little resistance against capsizing to windward.

Please find a way to keep doing these experiments. They are very interesting to watch and think about.

You should get some kayak boots. :o)

I don’t understand why there is little resistance against capsizing to windward.

First i have to apologize for such a late reply…
I have totally missed your post.

I attached two pictures that will (hopefully) explain it better than my poor attempt at writing technical stuff in English.

The righting moment comes from the part of the hull that lifts out of the water. Since there is more displacement at the lee-side, it will not have to be pushed down deep into the water before the windward side gets lifted clear of the water. I hope the pictures explains it better. Its easy to believe that it will heel around the line between the stems, but it heels around a line that goes through the middle of the displacement. That is why i think its important to have the ballast centered in the boat, and not to far out to windward.

Cheers
Johannes

Monoproa beam seas - Slow motion - Youtube

I found this old video of my monoproa. I think it has a very nice stable and calm movement sailing through some beam seas. One can see the stability at work.

Cheers,
Johannes