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Okay, so I build a crazy self-steering contraption...
and it actually works!!!

currently self steering a beam-reach from Bay of Islands towards Cavali Islands.

It's enspired by a "servo pendulum" design, but only uses junk you probably already have lying around. So far I have spent $30. $20 on rope and $10 on a pulley. (although I already had a few of those in my junk drawer)

So the design is a horizontal windvane, made from coreflute (aka coroplast) a door hinge and some bolts as a counter weight.

Then it goes to a little servorudder at the end of what was the boat-hook (which was previously a broom, before I lost the original boathook). Control lines go from the windvane to the servorudder, and then heavy lines go from the shaft of the servo to the tiller (and thus the boat's rudder)


The lines cross over, so that the gear tends to correct the boats movement - if it didn't cross over, movements due to the waves would get eccentuated, which could cause eratic steering (in theory, maybe I can change this)


It's actually pretty impressive that this cobbled together thing even works. And now that I've seen it in action, I bet I can improve it a bit too. The servorudder really isn't moving very much, and I can see it stalling sometimes. A longer better foil would improve this. The windvane is also held in place only with friction, and doesn't have much leverage over the servorudder.

There is also quite a bit of slop because I've used ropes for all the linkages, and adjusted them with trucker's hitches (a knot where you can add tension, which truckers used before they invented ratchet straps)

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It also worked on the quarter (45 degrees off downwind) I just adjusted the windvane and then the sails! to windward works too, but that is the easy one - just tieing the tiller off with a rope works to windward.

TODO: try dead downwind, stronger wind, lighter wind.

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I didn't understand all of that, but I'm impressed nonetheless. :boat:

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I found it surprisingly difficult to google for a basic explanation. It took me a couple of youtube videos to figure out what this contraption actually does in practice, I think.

So in a nutshell you can set a heading for the boat in relation to the wind direction, therefore using the wind as a kind of compass. Is that right?


@ktorn even better, using the wind as a helmsman. A compas just tells you what direction you are heading, the helmsman keeps you going in that direction.

The wikipedia page is pretty good, particularily the history section:

Also this article is good, (although unfortunately it complete avoids discussing the most interesting part, negative feedback to prevent oscillation) It covers the 4 most common configurations - but note that my trailing servo style isn't described - I have never seen or heard of anyone using this style, so it might be my invention!

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here is a close-up of the servorudder


The webbing strap plus wire and bolts seems to be rigid enough. Once the design stablizes I'll make a proper waterproof one sealed with epoxy, of course.

And I modified everything around the control lines and the power lines, making it easier to adjust (without having to stand on the duckboard) and reducing friction. Also I switched the wind vane pole for an old paddle (which I found washed up on the beach one time and kept, knowing it would be useful eventually) It has a handy mechanism for locking at a particular angle (twist the black grip thing) and also provides a disengage mechanism: slide it shorter, removing tention on the servo!

Easy control line adjustments:


vane pole moved outboard (provides a straight lead for the control lines, reducing friction)


and moved power line pullies, so they are at better angles, less friction and clearing away from other things stored on the rails (LPG tank, outboard)



This version is great! before it worked, but I didn't really understand why. Now it clearly works as I understand it to. Sailing on it now, back towards Bay of Islands.

Although, to windward im not really sure how much it's doing, because just tying off the tiller with a rope works pretty well. I think it's working slightly better that a rope does.


Excellent, now you can't use your sneaky pulling dingy out of the water unsportsmanship trickery to cheat at races anymore


this is amazing! also, hehe, enspired...


it's working pretty well right now, gotta resist temptation to post to ssb don't wanna get distracted and hit something! I need one of @substack's cybernomad rigs


Yesterday I was joined by Doug and we sailed from Opua in bay of islands to Oneroa on Waiheke island, in one go, in 34.5 hours.


At the start there was no wind, so we motored and took turns steering, until we got around cape Brett (that is the big right-hand turn) at that point, we had a very light tail wind so we raised the spinnaker to make the most of it. Normally the spinnaker is very finnicky to steer for, it likes to have the wind from just the right angle. With a human steering their mind wanders, and they let the boat go off course and the sail flaps and reminds them, but the mechanical self-steering keep course way way better! It sailed us down wind for hours, no problems! We made pretty great time in that stretch, around 5 knots.

But then the wind changed, to a westerly, and we had to switch to the genoa (large jib) again. It was pretty much a close reach or windward the rest of the way. We decided to sail through the night and took two hour watches. Two hours passed pretty quickly and was good enough sleep (and we were tired enough to fall asleep pretty quickly!). On watch there wasn't much to do but make sure we didn't hit anything, just hangout pretty much (and occasionally adjust the steering or sails)

Then the next day once we got past Kawau the wind picked up and we eventually reefed down to number 2 (medium) jib and double reefed main sail, bumping along quite quickly, and pulled into oneroa with still time to go spearfishing for dinner!

The self-steering struggles most when the wind is on the beam (coming directly from the side) I guess that is where the most weather helm is. I think if the servorudder was a little bit bigger it would handle that (also, I can see it stalling sometimes, because a wall of bubbles flys off the leading edge when it's trying to resist weather helm, but it's just a flat piece of 5mm plywood, so a proper foil shape would work much better)


Also, in Opua I upgraded the control line to 3mm dynema (which is low stretch and low friction) and better pulleys. The pulleys said something about kite surfing, they where $16 a pair, which was $6 more than the (shit) galvanized double pulley I had previously, but worth it. I still have some dynema left over. The total expendature is now $60.


and added this plastic smoother (a pen) which holds the line away from the edge of the aluminium pipe.


sailing is now just hanging out in the shady part of the deck



Were you in Mawhitipana? I saw a liveaboard Raven with a fiberglass tender yesterday, I yelled your name a few times but no response, and couldn't get through to your phone. I was in a raft-up with a mate (Highwayman, possibly still there, and another guy in a launch who is a big LiFePO4 nut). If not, head over to the next bay, I think you'll find your separated-at-birth twin!


haha @neftaly it wasn't me, but last time I was in these parts I met someone matching that description - John in "Penultimate" (name not written on boat, though)

I have large solar panel on pullpit, duckboard, and red plastic kayak on deck. CLEO written on bow and transom.


I made some improvements, and now it works on the beam, good enough anyway.

I made a much better fin - it's longer, and more fin shaped. It's sealed with epoxy. There is a hole drilled from the top, with a bolt into it. The green rope is epoxied on to reinforce what I expect is the most stressed part. Okay so I spent another $5 on rope but only used a tiny part on this. Shown next to the previous fin. Also I brought the control lines in closer to the pivot so it is more responsive.


Because the fin is more powerful, it broke pivot at the other end of the pole, so I had to make that better two. The second attempt worked.


It took a few tries to get this to all fit together right, but it works better now! I sailed back from mahurangi with 15-20 knots on the beam, to top of motutapu, no problem. Then today back to auckland with 25 knots to windward. Can tack by just turning the wind vane then, handling the sheets! (just don't trip over the power lines to the tiller) Maybe I can rig up a remote adjustment to the wind vane.

Oh yeah, the windvane wobbled a lot in 25 knots, maybe need a way to reef it?


this article is fantastic and relevant


@c3 oh regards the board steering, note that old ships (vikings, etc) put an oar like rudder over the side, rather than the stern, on the lee side, I think. Probably somewhat better for non-exausting steering. Although, with the extra length behind the boat, the rudder has more leverage.


Starboard = "Steorbord" = "Side you steer from" = most people are right handed so put it on the right = when you're heeled over with your steering board out of the water your steering sucks so you have PRIORITY over sailing vessels on other points of sail = GREEN = I AM RIGHT GET OUT OF MY WAY

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@dangerousbeans that makes sense! some cursory searching backs up your story. also, at one point left was "larbord" which was nice because it rhymed with starboard but that caused problems because you have to yell it into the wind and they might hear the other one, so they changed it to "port". Remember "there is a little port left in the bottle" (also note, that port wine is red and so is the port side light)


Ahh that's a good way of remembering

I always went with "starboard" has more "rrrrrrrrr" noise in it which is the same as "Right"
And right is the same as correct or green.


Another method is L comes before R in the alphabet, P comes before S

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@nrkn I still have to sing the alphabet song in my head to work out letter ordering :C

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@robinm haha, we have quite a few NZ boat people on here now! Yes, I definitely recommend Voyaging on a Small Income.

I'm pretty happy with the hauraki gulf currently - but working on ssb is my main thing currently, sailing is secondary. Next big trip I have planned will be to white island! (designing a learning curve that is not too steep) gotta go somewhere a bit further to give my homebrew steering system a good workout.


Having this week made a trip from Auckland, to Waiheke, to Great Barrier, to Kawau and now night-sailing back into auckland, it's a good time to update this thread on design progress.

The was noticing that the steering was getting a bit sloppy, and indeed the control fin would not just yaw but also roll. Examining the bit where the control fin pivots on the lever end - it was badly worn!


The bearing is a stainless steel bolt directly on a pretty thin walled aluminium tube, and aluminium is pretty soft so it's not surprising. I tried fixing this by rotating it and drilling another hole, but later realized that the original drill bit had broken at some point, and the new hole was oversized, so same problem. I found a hard(ish) plastic tube that fit snugly between hole and bolt... but the pressure between the bolt and the tube cut it, so I tried filling the end with an epoxy plug.


I used some rubbish as a plug, then poured epoxy into the end.


When that went hard, I had a working self steering again!
I was sailing with that from Kawau to Waiheke, and everything was going pretty well, then dolphins came (at night again - saw dolphins 3 times on this trip!) and then suddenly I noticed that the control fin was rolled way over, then I saw it barrel roll right around the lever!

I pulled it in and the bolt had snapped. Did a dolphin break it?
Anyway, I managed to get the snapped bolt out by cutting a groove in with the hacksaw and turning it with a screw driver.

Clearly, the control fin pivot is the most highly stressed part!
It's a fin about 500mm tall, canterlevered off a 6mm bolt going through 25mm tube. If that was a 50mm tube, it would be a lot better, with some sort of sturdy bearing... Solid plastic, and a thicker bolt... The level is also under torsion, so something with a higher cross sectional area will make that stiffer.

I want to not have to fix something every 50 miles!


@dominic this may sound like a silly question, and maybe was already discussed, but what's the feasibility of using a small 3D printer in the boat? The ability to quickly produce DIY plastic bits seems like a major feature when you're in the middle of the sea and don't have access to anything else.

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@Dimple if you love Jugaad I think you'd get on super well with @dominic

here are some choice pickings :

  • a bike made out of wood : %RDLWDUz...
  • a self steering thing for his boat : %AmpRntT...
  • a folding boat : %cj2YlRh... (this was actually built into a dinghy, but I can't find a link to that)

There are a bunch of other humans making rad things though. If you'd not seen #spider-farm , that's probably quieter now, but is worth a look - people living on the land/ ocean tends to bring out jugaad a bit I think

What makes me happy - being able to connect meaningfully with other lovely humans. Often it's close friends, but I've also enjoyed incredibly honest conversation with a stranger while sharing a meal in an airport.

@Turnstile Sai
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I am currently just feeling relief at being stopped. Although I spent much of the time just reading, I was constantly ready to jump up and attend to an emergency.

I departed about 3pm, two days ago, after going for a swim to scrape the bottom - I had a long way to go so going a little bit faster would make a big difference. But by the time I had all that ready, it was late afternoon already. Anyway, I knew I'd be sailing over night, so it didn't make so much difference when I left. I wanted to test the new self-steering, but also I wanted to test myself

The old-self-steering was enough to demonstrate that a design was possible, but it didn't really work that great. Since then I have been day dreaming about a better version of that design... in the last couple of weeks I built that on the hackland cnc:


Same basic idea as the old one, but everything is more deliberate. Anyway, that was ready last week. I was just gonna sail to waiheke, but it worked, so I kept on going. Also, @lucas and @dangerousbeans were out, so we all sailed to coromandel and hung out there a while.

I wanted to give it a good test - the previous one I had constructed in the bay of islands, and used it to sail back, so the obvious test was sail to the bay of islands. After a while, the perfect mix of fairly promising winds and not needing to be on a video call for a few days happened.

I set out in pretty light winds, but sailing smoothly, taking this opportunity to write some code: I had previously made a small js app that used the phone's GPS to tell me current location, heading and speed. I wanted to update that a bit to get average speed over the last minute, 15 minutes, etc... I took this opportunity to do that...

Until just a few hours in I was becalmed... right next to an island that I had camped on for a week, 11 years ago so I stopped to check how it was doing. The main thing I remember was: a lot of rats! It had gotten a lot bushier since then, maybe the rats had been exterminated. I didn't stay to find out. There was no wind, so I went back to my boat and made dinner...



And then just as it was getting dark, the wind started gusting through the gap between the two parts of the island! I weighed anchor and got underway. I was going fast on a beam reach, (sailing across the wind, the fastest point of sail).

But now I was getting quite remote, and sailed out of cell tower range, and then I discovered that the location api does not function in android chrome when a page is in offline mode! Luckily, I had this alcatel one flip phone, that would you believe it, has a modern browser in there, and had an older version of my demo app happens to be cached on it. That's how I navigated: get lat/long from the phone, and mark it on the chart every hour, using the compass as a rough guide where to point the boat (my boat is quite small and gets pushed around a lot by the waves so it's hard to sail it to a compass bearing more accurate than 5 degrees, and it's impossible not to veer from side to side in gusts too)

As I got around Coromandel peninsula, I turned and was now sailing with the wind on the quarter (from the back, but to the side) it seems this is the most difficult angle for the self steering, because the waves push you to the side. The wind was also building, in my log book I noted I had reefed the mainsail at 2242 (analogy: gone down a gear, for more control) But I made progress anyway, starting to pass great barrier island around 0130 hours... by 0400 I was passed great barrier, and just had the mokuhinau islands to pass to my port (left). At 0445 I put the second reef in the main, and set the jib poled-out, one sail either side, and it balanced down wind quite nicely.

All this time the self-steering was doing most of the work. I spent most of the time in the cabin, reading or taking quick naps (when not too close to hazards, such as rocks) jumping on deck periodically to check progress, or whenever their was a weird noise, or the the way the boat moved felt different.

At 0500 I noted that "a very slender cresent moon has just risen" Indeed, I realized that I don't think I had ever seen the cresent moon rise before - you need to be up very early. It was very thin and bright orange.

By 0630 I was clear of the mokohinaus, and now had only the pacific ocean in front of me. I took a longer nap this time, when I awoke, 0753 (I think I had an alarm for 8, I would never not set an alarm, in case the wind changed, and blew me back towards land) I realized this was the farthest out I had sailed.

Next, I had to figure out the next landmark the poor knight's islands. (I was disapointed to learn that the name of this island is nothing to do with a sect of knights that take a vow of poverty, but that someone thought the islands resembled french toast, aka, poor knights pudding)

Although the islands are towering cliffs all around, when I found them they where just a smudge on the horizon... so I sailed towards that.

At 930, I was getting hungry, I had breakfast, and second coffee. While relaxing with the coffee I heard a funny noise. It wasn't a banging, and it didn't happen again, and I was drinking a coffee, so I left it. When I did next go on deck, I was surprised to discover my jib (the front sail) was completely torn across!


I was surprised, because it wasn't even that windy! and this sail had already survived so much! This is my old sail that I practice sail repair on, so I'll have a good practice job when I get back to a sewing machine. The we were heading down wind, and the waves had settled, so I set the spinnaker and we tore off down wind towards the poor knights.


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