Simple, strong and safe rudders. Tunnel-rudders.
Then I had a crazy idea…...
A kick up version. Large hoops that could swing up past the back of the hull - ie not on the bottom but attached to the sides….. Crazy.
The problem i see with that solution is that large tunnel-foils are more of hydrofoils and would lift the hull out of the water at speed. If it were to kick back it would immidiatly pull the aft end of the boat down under the water. With enough speed it could probably pitchpool the proa backwards. A 1 meter diameter tunnel-foil with a 20 cm chord has a lot of power….
It would be quite a sight!!!
Cheers
Johannes
You have probably found out about the Amick Windmobile in your research but just in case you haven’t it is another vehicle that sought to reduce induced drag with a compact and robust lifting surface. There is quite a bit of information on the web, including a couple of Popular Science articles.
http://home.earthlink.net/~jameslamick/pop_sci/images/pop_sci_nov1976_windmobile_all.png
I have not seen the Amick Windmobile!!!
Thanks for the link. I very much appreciate this kind of info. I’m trying to read as much as possible, as there is soo much to learn.
Cheers
Johannes
Welcome Clarkey! Thanks for the link to the Windmobile. I’m finding it a little difficult to track down some technical info but will eventually, no doubt! It certainly looks like an amazing machine and a pretty neat concept - a hard version of Mal’s arcsail
A test anyone and everyone who is interested in this concept should do.
Cut a piece of a 2 - 4 inch tube and bolt some kind of handle on it.
My test-foil is a 1 inch piece of a 2 inch tube. I have not sanded it to any foil-shape.
I just attached a short bolt as a handle.
When i pull it through the water relativily fast at an angle i can not hold on to it with only two fingers. It will twist itself out of my grip. My girlfriend commented on how powerfull it was when she tested it.
Cheers
Johannes
My mind is working at an incredible speed today.
I got this idea on how to make an incredible simple and strong kanting keel on a monohull. This must have been done sometime somewhere. I can’t be the first guy to get this idea…
Its simply a circular tunnel-keel with the lead bolted on. The whole tunnel-foil should rest on some kind of wheels, so its easy to turn the keel as the arows indicate.
If it is possible to cant the ring forward and backwards, it would be a very effective way to trim the boat to a nose up or nose down attitude, to compensate for crew-weight, pressure from the sails ect…
Based on my tests with the small 2 inch plastic pipe i believe this keel is way to large, but it gives a clear view of my idea.
Please comment on this! I have searched google for something similar, but can’t find anything.
Cheers,
Johannes
I got this idea on how to make an incredible simple and strong kanting keel on a monohull. This must have been done sometime somewhere. I can’t be the first guy to get this idea…
Way to Go !!! Your FIRST KEEL PATENT !!!!!! I like it cheers Sven
Your FIRST KEEL PATENT
I don’t like patents, and I believe in a more open development model. I use Linux and the BSDs, i listen to music from jamendo (CC licens). The only reason to post this here is that i want to help the community at large to develop proas to be all they can be. This last idea is mainly for monohulls, and that is blasphemy on Proafile, but i can’t help elaborate and expand the ideas i get. I never post anything to get appraise or approval. I only want a vibrant and thriving forum where we all help each other.
That is where you come in Sven! You have contributed with lots and lots of very valuable data on proas.
Thanks!!
Cheers,
Johannes
Welcome Clarkey! Thanks for the link to the Windmobile. I’m finding it a little difficult to track down some technical info but will eventually, no doubt! It certainly looks like an amazing machine and a pretty neat concept - a hard version of Mal’s arcsail
Most stuff online can be accessed through the Amick estate website:
http://home.earthlink.net/~jameslamick/press/index.htm
The Windmobile was a fascinating machine with an excellent engineering pedigree.
Your FIRST KEEL PATENT
I don’t like patents, and I believe in a more open development model
Cheers,
Johannes
Aloha Johannes,
I was Joking, Neither do I , I hate patents, it are development stoppers, besides the daily stuff that I design ,engineer, produce and deliver, is copied constantly anyhow.
My policy towards commercial copying is , I step up the development pace a bit more , so they are too late every time, as such the real crooks will always stay in my wake…...... it works fine for years now.
cheers Sven
I’m getting a kick out of this thread.
I too figure that the legal cost of fighting copy artists is far greater than just staying ahead of them. Way to go, guys!
Besides, the real challenge is in making one’s ideas viable in terms of production and distribution.
I have searched google for something similar, but can’t find anything.
Jon Howes’ loop keel: http://www.boatdesign.net/forums/sailboats/radically-different-yacht-keel-loop-keel-16265.html. Scroll down to the post titled: “One specifically for Doug!”
One possible configuration of loop keel is to make it as a true circle when viewed from the front, or at least the top part including the bit through the hull, as a true arc. The keel can then pass through the hull in an arched trunking allowing the whole unit to be rolled relative to the hull. This can obviously then be used to move the ballast to weather without damaging the hydrodynamic properties of the keel.
This is obviously going to be far stronger than any current canting keel. If the keel rolling sustem breaks then the result will not be an uncontrolled hammering as occurs with current designs as the keel will still be fully constrained in its trunking and a simple locking emergency brake could clamp it in position without danger to the crew, allowing much more opportunity for repair.
Effectively, a canting loop keel.
P.S. Why does random punctuation get inserted into posts? When I preview, the word “scroll” shows up as “scro.ll”.
Most stuff online can be accessed through the Amick estate website:
Thanks Clarkey. I also received this link from Johannes for anybody else out there who’s interested in this -
http://tinyurl.com/d7s82tx
(click on “Sidan 102”)
Thanks for the link Robert Biegler!
I did not think i was first with this simple and efficient way, i’m more surprised that this is not more commonly used.
I hope i can testsail this one soon. I hope the ice melts this spring. We have an unusually cold spring in sweden this year…
Cheers,
Johannes
We obtained acouple of old Laser hulls and fitted one with a very crude loop keel with a ballast bulb (Clark Y section… more on this very shortly!) and a fin and bulb on the other with similar area. When we sailed them two things were apparent, the loop keel boat was incredibly stiff and so the dynamic righting moment was very evident also, the fin keel boat whistled straight past the loop keeled boat so this was only a partial success! A secondary observation was that inspite of the poor speed of the loop keel boat it did point higher and was able to keep sailing when pressed hard whereas the fin keel boat rapidly descended into a broaching display. Downwind things were even more dramatic with the loop keel being remarkably easy to sail even in a force 7 while the fin keel by then spent most of its time only marginally under control.
for example, although the area of the loop keel was more than that of the fin, when working back through the results the loop appeared to have about twice as much area as it actually possessed, a very weird result indeed! (I am still working on why this may be the case and it seems to be related to the enclosed flow path created by the loop).
My imidiate thought about this is that the loop was to large and “powerful”.
I have not read through the hole thread yet..
It seems to validate my idea of “more lifting power from a smaller foil”.
From the link Robert Biegler posted.
Very interesting reading
Thanks!!
Cheers,
Johannes