Barge-Proa once again. Videos.
I can hear you all collectivly groan of disgust and resignation..
“Not again!!!” “We had cured Johannes from this blunt-ended madness?!?!” “WTF?!?!”
Well, I can’t really help it. It must be side-effects of my medication (methylcobalamin). I am constantly drawn to extreme simplicity, and that tends to lead to the barge-shape.
The Triloboat, the PDRacer, the Optimist dinghy, the Thames river barge, the New Zeeland Scow, the Great lakes Scows….. The list is long. There must be something about the barge/scow that is very right. 300 years of blunt ends and flat bottoms, in a competitive, profit driven envirement - tells me to go looking in that direction.
I will test this proa with my new Crab Claw sail soon. If I am not to embarrassed over the results I will post some videos here.
The Barge-Vaka is 143 cm long, 12,2 cm wide, 12,9 cm high, It is 128 cm long at the waterline. There is a 15 mm negative deck rocker to keep the windage down. All that displacement far out in the ends will probably keep the ends on top of the waves with ease. It has a continous 5 cm rocker. The calculated weight with crossbeams and rig is 4,0 kg.
Cheers,
Johannes
I doubt that anyone that regularly visits this forum is qualified to cast the first stone regarding madness.
WTF, go for it.
If you’ve not seen it you’re in good company
http://thecheappages.com/proa/mary_plan.gif
Skip
Thanks Skip!
I found a good video of sailing heavy steel barges.
Quite good speed considering the weight and fat waterline (compared to our proas).
Cheers,
Johannes
I doubt that anyone that regularly visits this forum is qualified to cast the first stone regarding madness.
WTF, go for it.
If you’ve not seen it you’re in good company
http://thecheappages.com/proa/mary_plan.gifSkip
State of art in 1898 - see below, that is not supposed to sound negative. I like the idea of ultra shallow draft, I have long wondered in terms form resistance only the difference between a shallow draft hulls pushing a water down and a narrow hull pushing it sideways.
Tink
Thanks Skip!
I found a good video of sailing heavy steel barges.
Quite good speed considering the weight and fat waterline (compared to our proas).
Cheers,
Johannes
Thank you
I learned to sail on a Dutch sailing barge, a tjalk, running between the Frisian Islands and mainland. I tried to get my skipper to sail on the North Sea. He said I was crazy.
I tried to get my skipper to sail on the North Sea. He said I was crazy.
I’m sure a Tjalk can take a fair bit of heavy weather, but it would probably be quite nasty to ride out a gale on the north sea with one.
If one makes the Tjalk twice the lenght, half the width, half the weight with 4 times the righting moment and twice the sail-area, they could probably sail really fast, even in rough conditions.
Cheers,
Johannes
I sailed my Barge-proa today.
It was fast. Way faster than the green ASP. My wife was very impressed by it. “It sails soo much better than the other proas i have seen!” she said.
Very nice Johannes! I would expect the red scow-shaped hull to perform better than the green ASP even if for no other reason than it is a little longer and has much more waterplane and volume in the ends… so it will be less inclined to pitch-about and just get on with sailing. The wind and water conditions being more reasonable and realisitic helps greatly, of course…
It looks like another successful day for you; congratulations!
Have you considered adding your idea of rudders that fold flat against the transom ends when not in use on this design? I think it might work well.
Could you sail them side by side? Thats the best way to compare, don’t you think?
Could you sail them side by side? Thats the best way to compare, don’t you think?
Yes! I wish I could. I only have one sail and one set of ama+akas, and I don’t want to make another sail just for one test. It is more than a handfull to sail one proa at a time, and small differences in angle to the wind, sheeting of the sail, balance and pressure on the rudders tend to overshadow the difference between the vakas.
I choose to post those videos because I hope to inspire other to share their ideas and work. I don’t want to prove anything. Its only by sharing our experiences and efforts that we can create a thriving environment for development of proas and other shunting crafts. I sail these models as a way to cheaply test my ideas. I hope they can be of use and inspire people to try their own ideas. I don’t want to prove that a heavy barge shape is the best thing since sliced bread, I just want to show that a barge-proa is a viable option, among others.
I am very impressed by the simple barge-shape, and I really hope that more people dare to test it. I don’t know why it works this good. I hope to find out. My wife filmed both the ASP and the red barge proa. She immediatly said “wow!!! this one is so much faster than the green proa” when she saw it sail.
It looks like another successful day for you; congratulations!
Have you considered adding your idea of rudders that fold flat against the transom ends when not in use on this design? I think it might work well.
Thank you MTP!
That is a great idea. I will have to try it!
Cheers,
Johannes
I have been watching my videos of the Barge Proa over and over to get a feeling of their behavior going through waves. It is very exposing to watch them in slowmotion, sometimes even frame by frame.
I made two pictures of the Barge Proa going over a wave that clearly shows that it is not wavepiercing at all. There is a lot of vertical acceleration of the forward end of the hull.
This is the main problem with a Barge Proa. It would be quite tiring sailing in rough wheather. But if I compare this to normal monohulls in similar waves, there is not much differens. The monohull will also lean and roll sideways as a most unwelcome addition to the vertical acceleration.
What i do like about the behavior is that the hull seems to “fit” really good in the wave-system. There is no deep depression or hollow between the ends of the hull. The deep rocker seems to “fill” the depression between the waves. That will make the boat balanced and directionally stable, without much use of the rudder. This is very similar to Colin Archers rescue boats.
Johannes
Personally, I like the green proa.
Looking at the green and barge side by side, got me thinking….
What about a compromise - give the green proa some flare at the ends?
You would still have the fine entry and also the extra buoyancy forward/aft.
I’ve spent a big part of my life developing products and doing research. Certainly not in the marine industry, but the process is the same regardless.
Anecdotal analysis is dangerous, and the common practise of using anecdotal evidence to become basis for decisions as if they were facts is a mistake. Unless you develop a repeatable, documented and reliable testing criteria that generates adequate data samples to be normalized, it is impossible to reach conclusions about designs. The Internet is especially bad as a resource, as just about everyone has an agenda or cause they are promoting.
I know it sounds pedantic, but I drive my son crazy when he asks me “Do you like this?” about a product or brand. My automatic answer is “I don’t have enough information to make a realistic judgement”. People want fast answers and clear opinions - especially if they are in agreement with their own feelings. Aesthetics to most people and their opinions of beauty are a major force in making decisions - regardless of actual functional performance.
Sail boat design is a field in which romance, aesthetics, history-driven tradition and feelings are a major influence. Which is a clear reason why proas are the home territory of the crowd-perceived lunatic fringe. I’m proudly a lunatic fringe person - not because I’m a contrarian by nature - but because this is where my own logic has led me.
In this particular situation, it may be worthwhile to research tools available for iPhones and Android platforms that can record data from the GPS modules and internal position/orientation accelerometers. Sending out each sample unit and noting environmental conditions (wind, waves, etc.) while recording data would provide the ability to compare speed, response to waves etc. cheaply. The barge “looks” to be faster in the videos, but I’ve come to believe that fast, narrow proas look much less dramatic at speed than other boats. It would be nice to have evidence to make a clear determination. I’ll do little hunting for apps that may be useful. One waterproof bag, a phone in the boat and a couple afternoons testing could make a real difference in how we perceive designs.
—
Bill
A very simple solution could be to film the gps-unit with a GoPro, both laying on the bottom of the boat. We have a hand-held gps somewhere. Since the GoPro has such a wide angle of veiw it would record the waves, direction of the wind and more.
I will have to test it.
As I have said earlier, I don’t want to prove anything. I do this to learn. I trust my gut-feeling a lot, especially if backed by many hours of experience, all showing me the same thing over and over in wildly different conditions.
For every video I post here there is usually 10 more that I don’t post. The last 3 videos are the result of several hours of sailing the model. I see the same behavior regardless of wave-height, wind-direction, and so forth.
I even tested to sail the barge proa filled with water. I have a short video of that I could post if anyone is interested.
Thanks for the comments and ideas!
Cheers,
Johannes
A very simple solution could be to film the gps-unit with a GoPro, both laying on the bottom of the boat. We have a hand-held gps somewhere. Since the GoPro has such a wide angle of veiw it would record the waves, direction of the wind and more.
I will have to test it.Cheers,
Johannes
Sounds like a good idea. GPS don’t lie.
I do NOT mean that you do!!! But our perception is often very different from hard numbers.
I am always wary of statements like “oh, we were doing 12 to 14 knots at 30 to 35 degrees of true wind angle…”
Not yours, I know; but even on real boats, people usually thinks they are sailing faster than they really are…
GPS is a good way to make true; impartial, cold, comparison.
Cheers,
Laurent
But our perception is often very different from hard numbers.
I am always wary of statements like “oh, we were doing 12 to 14 knots at 30 to 35 degrees of true wind angle…”
Not yours, I know; but even on real boats, people usually thinks they are sailing faster than they really are…
GPS is a good way to make true; impartial, cold, comparison.
I know hard cold and impartial numbers are much more reliable and interesting than “wow! That is fast” kind of comments.
I will try to make a GPS-video soon. I feel a bit loonly in the “posting videos of Proa-sailing” department though…
Cheers,
Johannes