Barge-Proa once again. Videos.
I feel a bit loonly in the “posting videos of Proa-sailing” department though…
Cheers,
Johannes
You more Steven Soderbergh,or who ever else is you favourite film director, than a loony. I am firmly of the opinion that if you feel you need to say more than twenty words you should draw a picture… But if you can produce a video infinetly better. I love watching you videos and any other proa videos again and again.
Bill S is right about data but we need a little bit of, intuition observation and creativity also.
TINK
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Sounds like a good idea. GPS don’t lie.
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Ah but they do, but usually it’s an outrageous lie and easy to discard. Move your gps at just the right moment and your boat’s maximum speed (according to the gps) will triple.
In truth there is absolutely no better analysis tool than a recorded gps track which with some decent freeware will give you all sorts of objective data that is hard to come by any other way.
cheers,
Skip
Making a graph from GPS data (wikiproa)
http://proa.me/wiki/doku.php?id=making_a_graph_from_gps_data
Thanks tdem!
I will try this soon (this summer). I want to find a good place to sail it without the cord and without having to stand in the freezing cold Mjörn this time of the year.
I have been sailing my Barge-Proa today.. No videos good enough to post. I tested my oldest sons GoPro cable-tied to the aft end of the Barge-Proa. It is very difficult to get any overall view of what is going on. A microphone in direct connection with the hull records all kinds of weird and strange noices..
I made a mark at 30 meters on my cord, and klocked the proa to 25 seconds. 30/25 = 1,2 m/s. 1,2 X 60 X 60 / 1852 = 2,33 knots of speed. This is about 85% of the theoretical hullspeed. The models sails much faster the first 5 - 10 meters and then slows down considerably due to the drag from the cord. This is easy to see in the videos.
All in all I had a good day sailing today. It is soo much fun sailing the model and watching it sail straight through waves with ease. I think the Barge-Hull behaves much much better then it is supposed to.
Cheers,
Johannes
[I feel a bit loonly in the “posting videos of Proa-sailing” department though…
Cheers,
Johannes
Have you seen tsstproa channel on Youtube?
Anyway, I have taken pity on your lonely position as sole video provider and posted a couple of my current project.
http://proa.me/wiki/doku.php?id=tdem_s_boat
-Thomas
Thanks tdem!!
Yes I have seen Tsstproas youtube videos. Very interesting stuff. A lot of experiments and tests. He has inspired me. Since I like watching and learn from other peoples videos, I think the right thing to do is to post my own ideas and experiences for other people to learn from.
I love the smooth motion and easy paddling in your video. Your proa moves soo effortless and easy. Looks like a perfect alterative to a kayak. I would love to see more of the sailing, especially when you have sorted out the balance of the CE and CLR.
Cheers,
Johannes
I sailed my barge proa today. I clocked it at 30 meters in 16 seconds, which gives 3,03 knots of average speed.
This is 10% over theoretical hull speed. I think that is impressive given the extremly simple hull shape and that it is trailing a 30 meter long 3,5 mm thick cord through the water.
I mover the attachment point for the sail all the way forward on the bow, to give the sail a lower aspect ratio. The crab claw sail keeps on impressing me.
Cheers,
Johannes
Sounds very good, more performance from simple forms sound great to me
TINK
I’m impressed the model survives the mighty toss into the sea! The retrieval line is certainly slowing the boat, more and more as the boat runs out, so it’s difficult to get a feel for the speed and motion. I wish you had a small yet windy pond in which to test, that… or radio control! 😊
,,, or let the retrieval line spool out from onboard the model so that it is more like leaving a trail of string than dragging one from shore. Just remember to tie off both ends ; )
Have you ever watched videos of scow sailing, this one I bit annoying but some great footage
http://youtu.be/2NfUukfnUVk
I long time ago I read that when they healed and became a bit like a catamaran and this explained the speed. Looking at the footage I am sure there must be more going on.
In this one they appear to sail very flat
http://youtu.be/CSF6hnk_6J0
Tink
I read that when they healed and became a bit like a catamaran and this explained the speed. Looking at the footage I am sure there must be more going on.
They sure look like the slam a lot more than a catamaran!
That said, scow bows are clearly fast in the Mini6.5s—as discussed in an earlier thread. I wonder what folks say about the motion of the scow bow minis compared to the pointy ones.
Classe Mini boats and the inland racing scows are limited by their rules’ box dimensions, so it’s not so much about the shape of the bow as it is about optimising the rest of the hull for planing sooner under lifting sails off the wind: they are very specific in purpose. Given the opportunity all of these boats would perform better with a finer prow.
,,, or let the retrieval line spool out from onboard the model so that it is more like leaving a trail of string than dragging one from shore. Just remember to tie off both ends ; )
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That is an great idea!
I will see if I have something to wind the retrieval line on.
Thanks for a great idea!
I’m impressed the model survives the mighty toss into the sea!
1/4 inch plywood and lots of epoxy in a 4 foot model makes strong hulls! Many here seems to dislike my “battleship” approach to scantlings, but I have grown up with a tug-boat. I want my boats to be strong and durable.
Some day me and my family might depend on the strenght of the hulls to survive. Things can get really ugly out there. The north atlantic is a very harsh and brutal area on our planet.
Thanks Tink for links to very interesting videos!!!
The scows are really fast!!!
I wonder what folks say about the motion of the scow bow minis compared to the pointy ones.
Oddly enough the barge has much smoother and calmer motion than similar sized pointy ended hull. I am very impressed by the large damping of the hull. There is no resonant tendencys at all. It throws some spray when slaming into a wave, but there are solutions to that…
Cheers,
Johannes
Given the opportunity all of these boats would perform better with a finer prow.
Why?
I have seen that the scow bow brings a lot of positive attributes such as a much better damping of unwanted pitching - keeping the flow attached to sail and minimizing turbulence and stalling on the keel/daggerboard/rudders.
The straighter lee side will make a lot less resistance than the normal hull that is actually sliping slightly sideways through the water. It is more like a catamaran than a mono.
I can see that a finer bow will cleave through oncoming waves better than a scow bow, but other than that it does not seem to have many advantages.
Can you please explain why and how the scows in the videos would “perform better” with a finer bow?
(I see that this can seem a bit confrontational and that is not my intent. Im just curious, since my experience does not “agree” with your claims)
Cheers,
Johannes