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Getting Ready for SHTP 2021
- Thread starter AlanH
- Start date
I've looked it over, very hard more than once. The cockpit was a bit cluttered and broken up, and it had running backstays. Aside from that, it always seemed a very sensible boat, to me.
There's no way I can convince Joan to swap boats, now....and if I DID "swap" boats, there's a Wilderness 30 on my dock that hasn't moved in two years. The lifeline gate has been clipped open for two years...nobody has even been on board in all that time. A Wilderness 30 has been on my "short list" of boats I kinda always wanted for almost 20 years. Olson 911-S...Wilderness 30...and a couple others.
I'm committed to doing this in the Wildcat, now.
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After being very grumpy all night over yesterdays FAIL, and after looking VERY hard, for quite a while at Jan's vane, I see how he gets around the problem of the changing length of the distance that the cables cover, as he changes the heading. To replicate that, I'll have to make two more large-ish pieces and a mounting bracket....all do-able of course... but it make the basic premise of the vane carrier assembly "sleeving" over the mast, irrelevant.. I rather like the notion of the whole thing sleeving over the "mast" and I want to stick with it. It's super simple and rather light-weight.
I may have to go to a central push/pull rod linkage (I can use a carbon fiber kite rod, or some old fiberglass tent poles that I have.), linked by a bell crank to a "bent rod" actuator kind of system as per Walt Muray's work, or any of several commercial systems. THAT, I might have to do. We'll see. Before I do that, I think I'm going to spend $20 for ten feet of ptfe housing. PTFE = "Teflon" and you can buy flexible tubing made of the stuff. Running heavy monofilament (basically weed-whacker cable) though that, well slicked with Tri-Flow should be awfully slippery.
Before that, though, I'm taking the whole thing down to the port, tomorrow, with my 8 foot ladder, a mess of clamps, some grease and a pair of cable cutters. I will set the whole thing up in the closest geometric alignment to how it will actually be on the boat, and we'll see if changing the amount of cable housing and the amount of curvature of the cable, cuts the friction, substantially. It might not....or it might. We'll just see, tomorrow.
I may have to go to a central push/pull rod linkage (I can use a carbon fiber kite rod, or some old fiberglass tent poles that I have.), linked by a bell crank to a "bent rod" actuator kind of system as per Walt Muray's work, or any of several commercial systems. THAT, I might have to do. We'll see. Before I do that, I think I'm going to spend $20 for ten feet of ptfe housing. PTFE = "Teflon" and you can buy flexible tubing made of the stuff. Running heavy monofilament (basically weed-whacker cable) though that, well slicked with Tri-Flow should be awfully slippery.
Before that, though, I'm taking the whole thing down to the port, tomorrow, with my 8 foot ladder, a mess of clamps, some grease and a pair of cable cutters. I will set the whole thing up in the closest geometric alignment to how it will actually be on the boat, and we'll see if changing the amount of cable housing and the amount of curvature of the cable, cuts the friction, substantially. It might not....or it might. We'll just see, tomorrow.
More study of Jan Alkema's setup revealed something that I hadn't realized before. It's hard to explain but what it means is that the final turn of the control lines is centered over the axis of rotation of the rudder. THAT means that from that point..the final turn of the control lines, the distance to the pendulum oar "tiller" stays constant as the rudder moves. However, if you move that final turning point off of that axis, the distance DOES change...which is something I was trying to get around with the brake cable housings.
If I align the mast of the windvane right over the axis of rotation of the rudder, that simplifies things. It also means that today, I reduced the amount of brake cable...and brake cable housing by half. There's a transition from s.s. cable to a piece of inexpensive polypro line right now. I'll change that over to light dyneema, if this all works out. This has helped with the friction issue. So has grinding the ends of the housing totally flat and reaming them out to make SURE there are no burrs or protrusions to rub against the cable.
I might be at a point where a good breeze and a larger wind paddle could make this work.
If I align the mast of the windvane right over the axis of rotation of the rudder, that simplifies things. It also means that today, I reduced the amount of brake cable...and brake cable housing by half. There's a transition from s.s. cable to a piece of inexpensive polypro line right now. I'll change that over to light dyneema, if this all works out. This has helped with the friction issue. So has grinding the ends of the housing totally flat and reaming them out to make SURE there are no burrs or protrusions to rub against the cable.
I might be at a point where a good breeze and a larger wind paddle could make this work.
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Intermission
Member
Did you grease the cables too?
You bet...good old waterproof Phil Woods green stuff...and it made it WORSE...MORE friction. So I wiped it off and shot more TriFlow down in the housing and soaked the cable with it really well. The more I move it around, the smoother it gets, BTW.
Intermission
Member
I have a long Phil Wood story that I typed up here once, but then lost somehow.
What time will you be in RWC today?
tiger beetle
N/M 45 Tiger Beetle
This morning I got up and went reading about what you are constructing - that's a fascinating design, solves a problem in a clever way, and looks like it can be made to work.
My suspicion is that you're fighting friction and mass in the build. You want the air vane to transmit small amounts of movement to the water pendulum, and any friction in the system is bad. Any loss of movement in the cabling is also bad. Bowden cables are great for some things (primarily transferring tension) but have a lot of slop and friction as compared with rigid rods or tensioned cables on pulleys. Jan's notes mentioned using ball bearing blocks and wire to move forces from the air vane to the water pendulum - that might be worth trying with thin spectra line.
Is there any way to re-work the various bearing points (pintles, pivots) to use delrin bushings or ball bearings?
On the mass side of things, the less mass the air vane has to move the easier it should be to move that mass. In theory the lighter the air vane is the more sensitive it becomes while the forces it can transmit remain the same. Similiarly for the water pendulum - minimizing mass would make it easier to rotate/steer.
This is a really clever project - do keep going with the updates. As regards reducing friction, avoid high viscosity grease/oil and go with spray-on Teflon (e.g. McClube) or powdered graphite (e.g., ground up pencil lead or lock lubricant graphite). Anything to minimize viscosity, not trap dirt, and minimize friction.
- rob/beetle
My suspicion is that you're fighting friction and mass in the build. You want the air vane to transmit small amounts of movement to the water pendulum, and any friction in the system is bad. Any loss of movement in the cabling is also bad. Bowden cables are great for some things (primarily transferring tension) but have a lot of slop and friction as compared with rigid rods or tensioned cables on pulleys. Jan's notes mentioned using ball bearing blocks and wire to move forces from the air vane to the water pendulum - that might be worth trying with thin spectra line.
Is there any way to re-work the various bearing points (pintles, pivots) to use delrin bushings or ball bearings?
On the mass side of things, the less mass the air vane has to move the easier it should be to move that mass. In theory the lighter the air vane is the more sensitive it becomes while the forces it can transmit remain the same. Similiarly for the water pendulum - minimizing mass would make it easier to rotate/steer.
This is a really clever project - do keep going with the updates. As regards reducing friction, avoid high viscosity grease/oil and go with spray-on Teflon (e.g. McClube) or powdered graphite (e.g., ground up pencil lead or lock lubricant graphite). Anything to minimize viscosity, not trap dirt, and minimize friction.
- rob/beetle
Well, I took the contraption down to the Port, where there was a solid 15+ knots of wind oscillating through about 15-20 degrees. I'm sad to say, that the brake cable linkage friction almost completely prevented the system from functioning at all. It would "move"...when the blade was practically perpendicular to the wind, if you waited 10, 20 seconds for it to finally slip and GO. The wind vane itself is phenomenal. It's extremely sensitive and I think significantly more powerful than the old vane on my Naviks. However, the cable friction...no.
Not acceptable. OK, so that's the end of experimentation with the bicycle brake cables. Now I have extra cables and housing for my bike. **eyeroll**
I was down there from 1:00 - 2:00
This iteration of the linkage uses half the cable housing of what I had originally concocted, but that wasn't enough. I was right in guesstimating the amount I wanted, to allow for rotating the vane though 360 degrees without binding the cables, but it didn't matter.
Next up...PTFE cable housing liberally sprized with Tri-Flow teflon, with .080 in wede-whacker monofilament running in it. There are two, 6 foot bits of it hanging on 15 pound weights in my garage right now, to "assist" them in "forgetting" the tightness of the spool they were sold in.
Not acceptable. OK, so that's the end of experimentation with the bicycle brake cables. Now I have extra cables and housing for my bike. **eyeroll**
I was down there from 1:00 - 2:00
This iteration of the linkage uses half the cable housing of what I had originally concocted, but that wasn't enough. I was right in guesstimating the amount I wanted, to allow for rotating the vane though 360 degrees without binding the cables, but it didn't matter.
Next up...PTFE cable housing liberally sprized with Tri-Flow teflon, with .080 in wede-whacker monofilament running in it. There are two, 6 foot bits of it hanging on 15 pound weights in my garage right now, to "assist" them in "forgetting" the tightness of the spool they were sold in.
PTFE tubing...
https://fluorostore.com/products/ptfe-awg-spaghetti-tubing
I got size 8, ID of 0.12 to 0.14 inches, standard wall.
The weed whacker monofilament is .08 inches thick ....that should fit. I got ten feet, just in case this happens to be SO slick that I can go back to the full-length cable/housing setup that I originally wanted.
https://fluorostore.com/products/ptfe-awg-spaghetti-tubing
I got size 8, ID of 0.12 to 0.14 inches, standard wall.
The weed whacker monofilament is .08 inches thick ....that should fit. I got ten feet, just in case this happens to be SO slick that I can go back to the full-length cable/housing setup that I originally wanted.
I went down to the boat yesterday to check the fit on the companionway cover from the Santana 3030, that I adapted. Nailed it.
....though this is one of those jobs that serves the function, and looks good from 20 feet away, but don't get too close. Next up, get some 1/8th plywood and make the hatch scabbard, which will be in front of this cover.
I will need to replace the companionway board-retaining boards, to allow the companionway boards to be pulled out. The cover "leans back" a bit at the aft end, which limits the movement of the boards, coming out. This is fine, I've been meaning to replace them with aluminum ones, anyway.
Finally the cover is out of my front yard! sheesh...it's been WEEKS.
....though this is one of those jobs that serves the function, and looks good from 20 feet away, but don't get too close. Next up, get some 1/8th plywood and make the hatch scabbard, which will be in front of this cover.
I will need to replace the companionway board-retaining boards, to allow the companionway boards to be pulled out. The cover "leans back" a bit at the aft end, which limits the movement of the boards, coming out. This is fine, I've been meaning to replace them with aluminum ones, anyway.
Finally the cover is out of my front yard! sheesh...it's been WEEKS.
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Aha! This entire assembly seems to act as a wind steered trim tab. What happens with the tiller? Is it locked in a neutral position?
The trim tab would have to have some well balanced sails.
Onward.....
Ants
No, Ants, it's not a trim tab. It's a pendulum oar, but the way it acts on the rudder is completely different from how a more "usual" pendulum oar system, like a Monitor, works. A "usual" pendulum oar system is mounted on a framework on the back of the boat. The mast that holds the actual wind blade can be on the centerline, or slightly off from the centerline...or even quite a bit off from the centerline, but the pendulum oar is on the centerline (usually!...). In the usual configuration, the rotation of the pendulum oar is transferred to the tiller through low-stretch control lines.
In this vane, the pendulum oar is mounted on the head of the rudder, in a hinge, and it swings, just like a usual pendulum oar. However the pendulum oar is locked in place with lines to the stern quarters. It can still turn under direction of the wind blade, so that it gets pushed to an angle off from the direction of water flow, and generate a sideways force, but it doesn't swing. The geometry of Jan Alkemas system transfers the sideways force directly to the top of the rudder, causing it to turn, via that hinge mounting. There are no lines in the cockpit.
You have to read Jan's paper, and stare at it for a while for it to make sense...
WBChristie
New member
breezetrees
New member
I've been enjoying the progress! I have never been on a boat with a windvane and only vaguely understand the mechanics and was also wondering if it is a trim tab. I went back to look for the paper, fig 5 helps. It's complex and I hope you keep posting your results! I think: Vane pivots in the wind, cables make pendulum oar pivot on its pintles, this makes oar pivot on point P held by line, so the rudder head moves opposite the oar blade, and since the head has moved it also has turned the rudder? Is that close??
-Mike
Hey, electronics cognoscenti....
Lookie here.
See the compass on the starboard cockpit bulkhead? Now...see the plastic panel below that, which covers up a very old bulkhead cutout? If I put my depth sounder readout in that plastic panel, will that wreak havoc with my compass?
Lookie here.
See the compass on the starboard cockpit bulkhead? Now...see the plastic panel below that, which covers up a very old bulkhead cutout? If I put my depth sounder readout in that plastic panel, will that wreak havoc with my compass?
tiger beetle
N/M 45 Tiger Beetle
That will entirely depend upon the depth sounder readout display. Can you tell us what you're planning to put in the cutout?
On the other hand, if you treat an SSS TransPacific race boat as an Italian sports car, the first thing you should do upon starting is rip out the depth sounder and toss it overboard behind you - where you're going the sounder won't measure depth! (Italian sports car drivers do this to their rear view mirrors - at the speed they are traveling the only interesting thing is in front, never behind).
Could the compass be moved to port side into the other cutout?
- rob/beetle
It's a RayMarine i40 Dept readout which happens to be....rectangular.
I know, right? As soon as I'm past Point Bonita, who needs a depth sounder? But the SSS "outside the gate" racing rules say you must have a depth sounder, so I bought one...quite a while ago....and I'm going to get around to installing it here, pretty soon.
Yeah, I could move the compass, but my laptop and the AIS receiver were...in theory....going to live not far from there. However, the compass sort of ~has to~ work, so....