Sailing Directly Upwind

Well, it looks to me like the talking part is all done. What's left is the building of said item and showing a video as to how it does, or does not work.

I await the link to Youtube.

 

Yep! I'll work on my video skills; the last I shot a video the camera was shoulder-mounted so I may have some catching up to do!

 

If I'm in the area when you look to do this, I'll be happy to shoot it for you. A close friend who is a canoe designer lives in Grand Bend and I'm looking to visit him anytime after the water starts moving again.

So, keep us posted.

 

Terry
I agree, 1kph is not very ambitious. I have achieved 5.1kph with my backyard turbi-prop boat and Rob Denney got 11.5kph from his.

Having to reset the sail every tack will reduce the period of drive. I expect a rigid foil would set faster and drive for a longer time on each tack.

Rick W

 

This looks like a fun project. I'm trying to visualize how it works and think I have a mostly equivalent mechanism that is easier to understand. Would you say that this is pretty much the same as what you are suggesting except for the arc of the motion of the SM?

Imagine a rudder mounted at the front of a catamaran in such a way that it can slide back and forth from port to starboard (it's not used like a rudder, but this is the easiest way to explain it...). Start with the rudder all the way to starboard and turn it so that it would turn the boat to port if the boat were moving. Now, keeping the rudder from turning, whip it across the rails to the other side. It will move the boat forward. Now turn the rudder the other way and whip it back. It will move the boat forward again. That's the propeller of the system.

Now vertically mount a wing above the propeller to act as a turbine. They are mounted in such a way that when one of the foils is pointed directly forward, they both are. There is a geared rotation so that one one rotates so does the other, but not necessarily by the same angle. There is also some sort of mechanical linkage at each end of the rail such that:

(1) when the rudder/wing combination hits the starboard end of the rail, both foils are turned to port.

(2) when the rudder/wing combination hits the port end of the rail, both foils are turned to starboard.

Face the boat directly into a head wind and push the device against the starboard rail. The foils turn to port. Now the wind drives the wing, pushing it to port. The rudder is also driven to port and drives the boat forward. When the contraption hits the port end of the rail, they turn and reverse direction.

No matter which direction the foils are moving, the boat is driven forward. You can think of this combination of foils as a sailboat-without-the-hull that is tacking back and forth.

 

Chris: it would be great to meet at last: one caveat though, I'm in Alliston -about an hour north of Toronto -which is about a 12 hour drive if the roads are good. If you are passing through Toronto I can easily collect you and provide accommodation. I this one near the top of my priority list and I plan to be ready for the Spring. Is your friend Skip Izon by any chance? I recently read of his "Little Tripper" which is the same kind of boat as my Dora which is in the $100 boat challenge thread (his boats cost a bit more).

Rick: agreed, 1 k (knot) is pedestrian but represents about 100% improvement on the best VMG that boat has done under sail using a sail of similar size. In a tiny kayak with a small sail and the drag from the paddler it is hard to do better. The sail is self-tacking.

Dave: yes, that's the same principle. Your description is close to what I understand Rick was suggesting. Your rudder is acting like a fish tail or a yuloh, but at the bow instead of stern. We kayakers do that sideways when we need to get closer to the dock! The automatic rotation at the end of each "mini-tack" is something I think I can rig, once I see the thing on the water. Is this a concept or actual hardware?

 

Yep, Skipper is a long time designer buddy and I've been wanting to go out sailing with him for a very long time. Skip has a strong interest in sailing multihulls and I'll probably bring one of my boats along so that we can just simply get out on the water and sail.

Another canoe friend, John Hupfield, lives up by Parry Sound where he owns Lost in the Woods Boatworks. He runs a great, sailing canoe get together every year at Killbear Provincial Park and usually attracts some very interesting folks twith whom you'd probably enjoy hanging out.

Let's see what shakes out as you move along your path of discovery.

 

It's just a concept. I was having trouble visualizing how your idea is going to work so I tried to come up with something that eliminated the conceptual baggage of the towing and tacking. I'm not suggesting that my scheme would work better, but for me it is easier to understand.

As to your scheme, I confess that still can't see how it is going to work. You have been ambiguous over whether you have a hull on the SM. Without hull I can't see how you handle the forces and with the hull I can't see how you tack quickly enough.

I'd love to see some more details.

 

Chris: a few years ago I admired a lovely wooden sailng canoe at either Midland or Penetang, can't recall which. perhaps it was John's .

Dave: no ambiguity about it: the SM has no hull and is entirely supported by the beam attaching it to the towed hull. In an earlier post or two I used an analogy of a small boat towing a larger one to illustrate the operating principle in response to questions; sorry if that caused some confusion.

I have all the wood and half the Ally on hand and I'm off with my shopping list shortly. Before that I have to finish a boat or two and move them out of the workshop to make room for the work; before that I have to clean out the gutters so the boats don't interfere with the ladder; before that I have to take down the gazebo which is in the way and lower the pool level and fix a fence and ... sigh!

 

However, you don't take into account any of the torques, vertical and horizontal produced by the setup. Also, you come up with figures that are imaginary. The angles of tack and length of force vectors are made up to "prove" your theory. Nothing in all the data available on physics supports your claims. The argument that inventions in the past were met with resistance is not proof. The Wright brothers, for example, did not make wild claims but just built a flying machine. Deeds not words!

 

Terry
Where did the 1k = 1.15fps come from?

Rick

 

Dave
This link shows the water foil component of the drive system:
http://www.tailboats.com/images/Rear-view.mov

As long as the sail has more drive than the foil has drag it will oscillate.

It is not too difficult to set up linkages that will keep it oscillating automatically. A small flywheel will give it the energy to tack through the luff condition without human input.

You can also see why you would want to have transverse opposed foils to avoid the yaw and also neutralise the healing forces when using a sail.

There are other minor improvements that could be made. A twin foil system like this might do better than a turbi-prop.

Rick W

 

Rick: Oops, that's for mph. Should be 1.688. Min beam length is now 8 ft

Concerning the oscillation; it is more severe in the video than it should be for the sailing machine design. It is caused by the torque needed to move the blade sideways with the beam. The following is non-rigourous.
T = F.L
where F = force on blade, T = torque, L = beam length
Driving force ignoring friction = D = F if it is set at 45 deg

For the sailing machine assuming the same driving force:

sideways force on bow of towed hull = F.sin(A) where A = max angle between beam and centerline of hull
and torque on hull is H.F.sin(A)
where H = bow distance from center of lateral area or about half the hull length

The average torque is the integral of the torque over the range of the beam angle which is F.L for the paddle and 0.5H.F.sin(A) for the SM. Assuming in both cases the beam oscillates sinusoidally from +30 to -30 deg those values become F.L and 0.25 x H.F
Using my dimensions of L = 8 and H = 5 gives us values of 8F and 2.5F. I believe in practice the SM oscillating torque will be lower still, since the paddler must overcome blade drag by additional torque through the beam whereas drag is overcome within the SM system before any force reaches the beam. We will have to wait to see if that is correct.

 

If you guys do plan to get together in 2010, let me know - it is an easy six hour drive from here to Alliston and I'd come in a heartbeat. I spent a lot of my misspent youth camping in the Pinery Provincial Park in Grand Bend. Lots of great memories from the Bend.

Tricky little harbor there on the river that has a tight choke point on the jetty/entrance to the lake. Lots of beer dispensing locations and good breeze regularly.

--
Bill in Ottawa

 

Kayaker, it sounds like you are designing something similar to what I described except that it will move on an arm instead of on a slider? So why didn't you say so . It's interesting that we have opposite ideas of what makes it easy to understand.

One thing I that occurred to me in the slider design is that the wing is always on a beam reach when going upwind and it is getting the benefit of faster apparent wind so it is actually producing its peak output going upwind (whether this applies to the mechanism as a whole, I don't know). It seems that your system would be the same, right?

Rick, I'm surprised that you think this might do better than a turbiprop. You have said in other threads that long and thin foils are more efficient, but wouldn't this mechanism require a broad foil to generate enough power?

But it would be interesting if it could be made efficient. Suppose you do a two-wing system as you suggest. When the boat is going upwind, you would have the mechanisms to produce power directly upwind and the wings would be effectively on a beam reach. When the boat is on a reach, you fix the wings in place and use them like regular sails. When going directly downwind, you reverse the system like in the DDWFTTW thread. Given the versatility, I wonder if this system might not be optimal in all headings.