kleppar

Self steering trimaran

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I am having a 23 ft. cabin trimaran built, with rotating carbon mast and twin rudders. I will have self steering, and am contemplating the following options:

1. a simple cockpit autopilot, e.g. Raymarine or similar

2. a fancy NKE autopilot; supposed to be state of the art

2. a mechanical windvane (Mr Vee and Windpilot have lightweight units around 10 kg)

3. a combined windvane/autopilot (Windpilot); see below (copied from Windpilot´s website); photo here.

Catamarans

  • If the wind is particularly gusty, a more reliable steering signal can be obtained by removing the windvane and using a small cockpit autopilot attached to the windvane hanger to control the pendulum arm instead.

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Wind vane cant be used on fast boats, they can't follow apparent wind variation.

Raymarine single cockpit autopilot with a light battery and a solar cell is all you need !

I used this on my 23 ft Tremolino and it worked great, you can even tack with the autopilot.

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I use a raymarine with a battery pack attached on top (a beatit car start (https://smile.amazon.com/B7-Pro-16500mAh-Portable-Lithium/dp/B07GN5HHXJ/ref=sr_1_6?crid=1O4Z4KGRE6J8A&dchild=1&keywords=beatit+g18+2000amp+peak+12v+portable+car+jump+starter&qid=1593283613&sprefix=beatit%2Caps%2C405&sr=8-6 )).  Shortened the cord so it is simple, the beatit is already waterproof and has a capacity indicator built in).  Good for daysails and the lithium battery lasts  a couple outings without recharging (16Ah).  If planning on doing passages (say tween oslo and gdansk), you'd want something more--especially if no one is tending tiller.  The times it uses most power is when going downwind with swells from behind-whether or not you have spin up--short w/l boats tend to swivel in swell (worked that way as well on my F24).  Of course, if doing passage making you will likely have nav lights and other stuff that needs an electrical system.

Screenshot 2020-06-27 at 12.07.42.png

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patzefran why do you say you cant use a windvane on a fast  boat? and how fast is fast. I've heard this before and while I get that on a boat running 20knots that does make sense (based on reaction times and gain etc) I fail to see why this seems to be applied to all multis. To me its just a case of getting the boat up to speed prior to engaging the windvane to avoid a vastly different course to the initial one.

 

Windvanes always work on apparent wind its just that us multis have the ability to create a higher % of it compared to slower boat. 

 

Cheers

Mark

TT720 slow trimaran

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20 hours ago, MultiThom said:

I use a raymarine with a battery pack attached on top (a beatit car start 

Screenshot 2020-06-27 at 12.07.42.png

And, if you find that you may need it longer than 16 aH.  You can carry beatit spares since they weigh very little (they also have 22 aH versions).

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20 hours ago, MultiThom said:

I use a raymarine with a battery pack attached on top (a beatit car start (https://smile.amazon.com/B7-Pro-16500mAh-Portable-Lithium/dp/B07GN5HHXJ/ref=sr_1_6?crid=1O4Z4KGRE6J8A&dchild=1&keywords=beatit+g18+2000amp+peak+12v+portable+car+jump+starter&qid=1593283613&sprefix=beatit%2Caps%2C405&sr=8-6 )).  Shortened the cord so it is simple, the beatit is already waterproof and has a capacity indicator built in).  Good for daysails and the lithium battery lasts  a couple outings without recharging (16Ah).  If planning on doing passages (say tween oslo and gdansk), you'd want something more--especially if no one is tending tiller.  The times it uses most power is when going downwind with swells from behind-whether or not you have spin up--short w/l boats tend to swivel in swell (worked that way as well on my F24).  Of course, if doing passage making you will likely have nav lights and other stuff that needs an electrical system.

Screenshot 2020-06-27 at 12.07.42.png

Is there any magnetic interference from the battery pack?

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1 hour ago, cyclone said:

Is there any magnetic interference from the battery pack?

I wouldn't know since I don't bother to calibrate the compass.  

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18 hours ago, Try Flying said:

patzefran why do you say you cant use a windvane on a fast  boat? and how fast is fast. I've heard this before and while I get that on a boat running 20knots that does make sense (based on reaction times and gain etc) I fail to see why this seems to be applied to all multis. To me its just a case of getting the boat up to speed prior to engaging the windvane to avoid a vastly different course to the initial one.

 

Windvanes always work on apparent wind its just that us multis have the ability to create a higher % of it compared to slower boat. 

 

Cheers

Mark

TT720 slow trimaran

Obviously, You can use a windvane on any sailboat, but as you say, on a fast one the apparent wind direction has higher amplitude variation and unless strong lowpass filtering the autopilot will order higher amplitude course variations. As for the velocity treshold, it is a matter of experiment. Anyway, I should not use a windvane on a multihull, except perhaps an heavy cruisingt one

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Multis tend to lack the same cockpit mounting points as small monos.

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On 6/28/2020 at 6:54 AM, MultiThom said:

I use a raymarine with a battery pack attached on top (a beatit car start (https://smile.amazon.com/B7-Pro-16500mAh-Portable-Lithium/dp/B07GN5HHXJ/ref=sr_1_6?crid=1O4Z4KGRE6J8A&dchild=1&keywords=beatit+g18+2000amp+peak+12v+portable+car+jump+starter&qid=1593283613&sprefix=beatit%2Caps%2C405&sr=8-6 )).  Shortened the cord so it is simple, the beatit is already waterproof and has a capacity indicator built in).  Good for daysails and the lithium battery lasts  a couple outings without recharging (16Ah).  If planning on doing passages (say tween oslo and gdansk), you'd want something more--especially if no one is tending tiller.  The times it uses most power is when going downwind with swells from behind-whether or not you have spin up--short w/l boats tend to swivel in swell (worked that way as well on my F24).  Of course, if doing passage making you will likely have nav lights and other stuff that needs an electrical system.

Screenshot 2020-06-27 at 12.07.42.png

We used a setup like this on a Kurt Hughes 26/28.

Other than the Raymarine stuff having a lousy actuator... It worked great. That boat was a 1.1 X TWS boat for us.

Though I have used a Cape Horn on long offshore passages on a mono, I have tried and failed (see pic) Side_View.png.5e8d8740c3f92e780e069f61a725c294.pngI would not attempt windvane steering on fast trimaran. Maybe? on one that was a <0.6 TWS boat, but the two trimarans that I have sailed long distances on have acted differently with changing AWA (this with regards to hull speed/wind speed multipliers), so be careful.

As an aside.... If you have the ability to mount a full fledged tiller steering unit (separate fluxgate compass, CPU, and power source) I can attest to the fact that the Raymarine actuators are complete junk. We are 1/3 the way around the world with tiller steering and we absolutely destroy a Raymarine drive on less than one long passage.... However the Pelagic https://pelagicautopilot.com/  can go over ten times the same distance and still be working with their 'Standard Unit' on a 40 foot trimaran. 

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Thanks; so far I have learned that a windvane alone is probably not a good idea. What about the combination windvane and autopilot (see photo below)? 

I have already contacted Pelagic, and am waiting for their response. Same for NKE France.

Autopil.jpg

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I don't see the point in doing this because the Palegic drive is way strong and durable enough to steer directly on your tiller. Why complicate things? (or have I missed something about your install?)

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22 minutes ago, kleppar said:

Thanks; so far I have learned that a windvane alone is probably not a good idea. What about the combination windvane and autopilot (see photo below)? 

I have already contacted Pelagic, and am waiting for their response. Same for NKE France.

Autopil.jpg

I watched  (Youtube) one guy sail his 25 foot monohull from LA to Hawaii.  He had two separate units.  Windvane for most of the time but used the electrical autohelm when strict course keeping was worth (like when nearing port).  The issue with a single dual unit would be the unnecessary power use if wind control is adequate.   As 2flit says, raymarine units are not the most robust.  Personally, I'd wait to get the Libertist, do some sea trials then figure what you need for whatever passages you intend to do.   You can count on having unexpected issues with a new design and a brand new boat.  No telling what the foils will do to that heavy hull in a seaway.  

 

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The combined unit saves electricity; this is probably more important for long passages when not being able to charge batteries. However, it is an intriguing combination:

https://pelagicautopilot.com/products/autopilot-for-windvane-self-steering

Windpilot offers the same, with a unit much lighter than Monitor.

I am tempted to go for an NKE autopilot, provided it is not too expensive.....

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Sorry for posting twice about the same......

The stern of Libertist 703 will look similar to 853, except that 703 is a folding tri:

libertist853ar.jpg

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if you want responsive you have to go for electric pilot. Important factor for multi is the quality of the compass sensor, and for this you want to get an unit with a gyrocompass. I have a R.aymarine evo 100 on my 34 ft tri and it works great (wind mode and compass mode).

Yes, NKE is more robust but unless you do oceanic passages I dont think you need this extra quality  - better get a second  drive unit as a spare, or maybe a drop-in replacemnt like MultiThom’s kit. 

By the way some long time ago I sailed in your nice country from the Lofoten to DK in a 24 fr sloop, with a Navix windvane - no autopilot, good memories, but nowdays, technology has changed and I would 100% do it with an autopilot+solar panel. And a Tiller clutch.

 

 

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I have a question on autopilots I have always wanted to ask, so.......

Are the wheel mounted ones using a belt more robust than the tiller versions with the ram ?

From what I've seen the tiller versions are inevitably more exposed and it looks to me like the drive ratios on a wheel version would be less likely to suffer from overload ? Any useful comments ?

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Good evening,

A 1000 tiller pilot is plenty good enough for a 23ft tri. The helm on a little tri is so light. A multi tracks well (or should track well) and the autopilot doesn't work that hard compared to a same size monohull. The tiller hardly moves. The battery drain will be minimal.

I had a Farrier F9 trimaran with a Simrad 1000 tiller pilot. We sailed the boat 1 800 miles trans ocean, two up and the little tiller pilot coped well.

Keep it simple. Keep it light.

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I just remembered Dick Newick, used centerboards to help self steer balance in many of. his early boats, a lot of what he did merits a. closer look.  As a design purist it is hard to beat his thoughtful work.

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My boat will have fixed foils in floats, twin rudders and a daggerboard, so I guess it will be quite directionally stable.

Libertist exterior5.jpeg

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On 6/28/2020 at 7:39 PM, kleppar said:

Thanks; so far I have learned that a windvane alone is probably not a good idea. What about the combination windvane and autopilot (see photo below)? 

I have already contacted Pelagic, and am waiting for their response. Same for NKE France.

Autopil.jpg

I had a Pelagic autopilot (no windvane).  It was a great piece if kit.  Sold it with my boat.

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I'd be very interested in hearing from those that have tried a mechanical windvane on their multi. Just to get my head around the issues experienced. For me its just an interesting project for our TT720 which would definetly be on the slower end of the multi spectrum. I'm not planning on any blue water adventures but am intrigued to try one out on our sails down the coast. 

I personally didn't warm to the constant whirrr whirr of our old autopilot.

I'm actually a techie at heart but love the clockwork gadgetry of a functional servo pendulum. The ability to have predictive steering and gyro feedback with gains tailored to current sea state etc etc  make the electronic versions a amazing bit of kit these days but the old world charm of a mechanical feedback loop is still pretty cool in my books.  

 

Cheers

 

 

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Well, this was exactly what I also had in mind. If sail by compass course is most important, the probably an Autopilot is best. But what is sailing by apparent wind is most useful? Apparent wind sailing is standard operating mode for a windvane, but for an autopilot to sail by apparent wind, complicated instruments are required, as I understand it.

It seems that several of you do not believe that a  windvane is sufficiently responsive on a fast trimaran. Is that really the case?

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My initial gut feelingis actually the opposite and  that they may be too responsive given the faster AWS and AWA changes as well as speed thru the water increasing oar leverage. But that said AFAIK its a basic feedback loop that needs to be adjusted to get the correct Gain in the system. That is part of the reason I'm tinkering in CAD to design my own as off he shelf variants may just be tuned to the more standard and slower craft  that they are usually mounted on. 

My gut makes me think that one needs to reduce this gain proportionally to speed thru the water in the same way one doesn't make large course corrections when driving at highway speeds. Likewise some form of filtering is needed to avoid reacting to fast moving transients and rather follow trends. These issues are present in electronic devices just as they are in mechanical systems so its a design challenge IMHO.

 

 

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Sorry, being a non native English user, and not terribly technical, but what is AWS, AWA and AFAIK?

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Upwind going to weather, not usually a problem with changing AWA with gusts or lulls.  OFF the wind, is another issue.  Just yesterday, I was on a reachy course with lots of gusts and lulls.  Apparent wind changed 40 degrees in 10 seconds as the sail plan filled, the boat accelerated and then as the sailplan stalled, apparent wind changed again.  The autohelm (electric) certainly was hunting trying to keep a steady compass course....dunno what an apparent wind device could have done.  Similarly, off the wind in any kind of waves, the electric autohelm has difficulty keeping compass course-sliding down (surfing) a wave, yawing at the crest....  

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Gusty, reaches are the time to be hand steering with sheets in hand, I wouldn't trust either setup in those conditions personally. 

In  a steady wind reach/run I would think the strategy would be  to get the boat up to speed and drive the apparent wind fwd prior to engaging the windvane. At that point the wind vane would drive down as the boat accelerated and lift up on easing wind or slowing as effectively your back to upwind sailing.

I see autopilots/windvanes (of all sorts) as aids when its easy/boring sailing not to replace the nut behind the wheel in more challenging situations.

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Chiming in late here... a friend equipped his good-sailing Farrier F36 with a wind vane for crossing the Pacific. Didn't work out; as some have supposed here, the unit couldn't keep up with the apparent wind fluctuations as boat speed varied up and down ocean waves. He removed it from the boat after one long trip. That boat has a few years of great success with the simple Pelagic auto-tiller. I copied him on F36 Ravenswing, and it was fantastic during my 2,500 miles so far. 

I have an Autohelm brand wind vane, never used, available for sale near San Francisco. contact me thru cartersboat.com   After the other F36's experience i didn't even bother finishing my install of that nicely made wind vane.  The Pelagic is easily powered by solar panels. 

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Thanks for all good advise. I shall go for NKE or Pelagic, and drop the windvane idea....By the way, is the Farrier F36 similar to Corsair 36? I notice there is a Corsair 36 for sale in Norway at present; from 2005, at around USD 90,000.

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4 hours ago, kleppar said:

Thanks for all good advise. I shall go for NKE or Pelagic, and drop the windvane idea....By the way, is the Farrier F36 similar to Corsair 36? I notice there is a Corsair 36 for sale in Norway at present; from 2005, at around USD 90,000.

Good evening,

No, they are very different.

The Farrier F36 versus the Corsair 36 was a sore point for Ian Farrier. The Farrier F36 is a serious offshore trimaran. One of the early ones has circumnavigated.

Th Corsair 36 was not designed by Farrier.

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7 hours ago, kleppar said:

Thanks for all good advise. I shall go for NKE or Pelagic, and drop the windvane idea....By the way, is the Farrier F36 similar to Corsair 36? I notice there is a Corsair 36 for sale in Norway at present; from 2005, at around USD 90,000.

Here is the long answer to your question:

With this question; you may have waded into a little maelstrom of inuendo, controversy, rumor, and potential fodder for the SA crowd. They are different boats and Corsair liked to say that Ian Farrier ’started’ the design work on the F-36 while  he was still at Corsair (before he left in a veritable sea of controversy and mutual aim takings). It’s a sad bit of history in the carriers of these two branches of thought about production trimarans. The two boats are different and yet similar and often verbalistic ‘confused’ since they had similar origins in design and development with names only separated by an F or C…,. with all the earlier boats that Corsair continued to produce (after Ian left) retaining the “F” moniker to just confuse newbies more thoroughly! 

The F36 and F39 were all boats built to plans Ian Farrier supplied after he left Corsair. They are often home-built, and occasionally custom-built by a professional boat building firm. Most/Many of the F36 were lengthened at build to be 39+ feet on deck, hence the F36/39 designation that is starting to develop. The true plans built F-39 was a folding boat (sometimes built with a $30,00USD Farrier supplied folding ‘kit’) while the F-36 and lengthened versions of it were all “demountable”. Ian liked to say they came apart in 4 hours onto the plans built trailer, I would say it takes more like 4-days to take one down or set up. But they were both trailer-able. There are other notable differences in the F36 and F39 such as mast height and options to rotate and so forth but the added length and true foldabilit5y were the key differentiations in my mind. A true F39 is roughly worth at least $50,000 more than a F36. There are enormous differences in build quality and weights with all the Farrier F36, F36/39, and F39’s and its buyer beware because a few of they are horribly overweight with transoms that are submerged even before stores are put aboard. They are good fast cruisers, not as fast as an F31 in calm waters but will do a horizon line job on an F31 in offshore rough conditions.

The Corsair built C36 is common to see for sale. They are all “Factory Built” boats. The C36 has been much maligned by Farrier advocates. There was one down in Texas of especially ill repute that had is referred to having bulkhead failures and issues with the beam support pockets. The internet is a bit rife with derisions of the C36 and occasional reference to quality issues at the factory with some builds. It’s all rumor and fodder for disagreement. My best take on all this is that the C36 is a fine boat and really a coastwise cruiser, not anything like as nimble as the C31 but a fair bit more commodious inside. I personally would not venture far offshore in one of the C36 models, but I don’t really think that this warrants the disparaging comments that populate the internet on this design and build. I would strongly encourage the F31 over the C36 because the F31 can still barely hang in there as a true ‘beach cruiser’ while the C36 is a bit ponderous for this type of sailing.

 

As background… I am about 1/3 of the way around on a circumnavigation in a Farrier F36/39. Left Canada in 2017 and were are winter/summering Covid-19 on the North Island of New Zealand. I can attest to the fact that a well-built F36/39 is an awesome trimaran offshore. She has gone to windward in 45 knots of wind with 65 Kn+ gusts with dignity and aplomb. Ian designed a fantastic offshore boat. She sails like she is on rail downwind in 30kn, a mesmerizing experience in the moonlight

IMG_4525.JPG

IMG_4517small.JPG

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Well, I have no intention of buying the C36 advertised for sale in Norway. My Erik Lerouge designed Libertist 703 will be ready by the end of the year - the plan is to have it exhibited at the Düsseldorf boat show.....

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I use the Raymarine autohelm on my clunky old tri in Hawaii.   It's very useful for me because I am often out single handed, so very nice the set in place while I am up on the deck raising or lowering the main for example.   However, I don't use it that much out on the big water.  A typical sail for me will be heading upwind towards Diamond head from Keehi for an hour our so, then turning around and coming back downwind.  When heading upwind I try to go as tight to the wind as I can and the wind is constantly shifting quite a lot, so most days I would have to fall off quite a bit or be constantly adjusting the auto pilot.  Also, we have kind of a lot of surface swell here and I feel like I can go quite a bit faster upwind if I kind of dodge in and out of the swell a bit rather than just trying to literally slam though it.   Coming downwind with a significant following sea, I have not really had much luck with it.  Without a spinnaker up most days I am not going quite fast enough to surf, so the swells are rolling under the boat, and as that happens I have a variation in how much rudder is in the water, and the boat also feels like it wants to try to turn to 90 degrees with the swell.  For me it is a fun challenge to try to optimize speed and surf as much as I can, but the auto tiller just cannot manage it at all.   Under correct, over correct, over correct, and in about a minute or so you are at 90 degrees to the swell with the auto helm all the way against one stop and beeping.   There are adjustments to the control loop logic in the auto helm you can make, but so far I have not fiddled with this because I feel like, when I am steering in this condition, I am taking into account how the tiller feels, and what I see about the bump that I am riding or that is rolling under me.  With only compass direction data I don't think I could manage it either.

I understand that there are places in the world where you can have good wind and a reasonable smooth water surface.  If that is true then an auto helm would be much more useful there than here.

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Very interesting to read the differences between the Farrier designs.

Kleppar, you might want to check the mounting instructions for whatever autopilot you settle on, some of the tiller pilots might be a challenge to mount on that design and it looks like there isn'rt a quadrant below decks. Lerouge should have an idea what works with his designs. Another issue is accounting for a rotating spar, been wondering if it isn't simpler to mount the windvane away from the mast.

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Good point; the shipyard will mount the autopilot; there is a similar boat (853) with an autopilot, so hopefully this will be done professionally.

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