Boat auto-steering:
auto-pilot and windvane

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This page updated: December 2008

Auto-Pilot driving Windvane


Auto-steering types:
  • Auto-pilot steers to a specified compass heading.

  • Windvane steers so that wind hits boat from specified constant angle.

  • Balance the boat and then lash tiller/wheel; hope wind/course doesn't change. (Tiller Stay)

  • Run main or jib sheet to tiller (diagrams in "Singlehanded Sailing" by Richard Henderson; John Ward's "Sheet-to-Tiller Self Steering").

SailNet - Paul and Sheryl Shard's "Self Steering Gear"
Self-Steering designs by Walt Murray
Excellent tutorials at Scanmar

From Rick Kennerly on IRBS live-aboard mailing list:
First things first. The most important consideration in buying a windvane [or auto-pilot, probably] is ... having a boat that balances. If you can't find a combination of sail, trim, and mast rake that allows you to hold your tiller between your finger and thumb in 10-15 knots, all windvane experiences will be unsatisfactory. Wheels camouflage bad weatherhelm, not cure it. If your rudder is over more than about 15 degrees with a wheel, your boat's not balanced. Also bad trim, being down by the head or squatting at the stern, can make a boat more difficult to steer. Until you get to this point, you're not ready to begin fooling with a vane.

From Dan Blanchard on the WorldCruising mailing list:
I have noticed that many cruisers complain about their windvanes and end up going to an electric unit which normally fails for them as well. I have come to the conclusion that many "yachties" have no clue on how to balance their sail plan to reduce excessive weather helm. This is a big issue for wind or electric vanes. I always sail the boat by hand for 15-30 minutes prior to setting up the vane to insure that I have her balanced as well as possible. If conditions change I often go through the same process again so that the vane does not have to work hard to keep us on course.

Auto-pilot versus Wind-vane:
Auto-pilot better:
  • Steers in light/no wind and downwind.
  • Steers while motoring.
  • Less chance of going off-course (because of wind-shift).
Wind-vane better:
  • No power required.
  • More reliable.
  • Steers better as conditions get worse (stronger wind).
  • Not affected by magnetic or electrical or RF interference.

From Michael Meeker on The Live-Aboard List:
I bought Letcher's book [Self Steering for Sailing Craft] years ago and tried to implement his thoughts on my sailboat. The short of the long is that this stuff [sail-to-rudder connection] just does not work on enough points of sail to be reliable. There is nothing like a quality self-steering vane or, better yet, a great autopilot for distance work. You can't go cheap, but that's a lesson that is hard to learn for most of us.
From Pierre on The Live-Aboard List:
I used his ideas on my previous boat and they worked. It does take a while to figure out on each boat, but they do work.


Servo-pendulum wind-vane parts:
  • Air vane (or "sensor vane"): sail or board on top that is moved by apparent wind.
    Different sizes for light and heavy air.

  • Water vane (or "servo rudder" or "oar"): when water vane is turned by air vane, passing water forces the water vane to pivot sideways.
    Want collision protection.

  • Linkage between air vane and water vane: usually gears, levers, rods.
    Low friction very important; want low "play".

  • Steering: can be
    • Boat's normal steering: tiller or wheel or hydraulics or cables to rudder.
    • Auxiliary rudder.
    • Trim tab on trailing edge of boat's rudder.

  • Linkage between water vane and steering: depends on type of steering.

A non-servo-pendulum system would skip the "water vane" part, and have some direct connection between "air vane" and "steering".

Steering types:
  • Linkage to boat's steering. Harder to install than separate rudder. Cables can add friction.

  • Separate auxiliary rudder. Backup for main rudder and steering, easier to install, but more hardware on stern, may have to lock or lift it while motoring or backing up. Better for hydraulic-steering and center-cockpit boats ?

  • Trim tab on trailing edge of boat's rudder. Works best if light boat. Linkage can be a bit tricky ?

SailNet - Paul and Sheryl Shard's "Selecting a Self-Steering Windvane"
Darrell Nicholson's "Self-Steering - with No Strings Attached"
Articles by Darrell Nicholson in Jan and Feb 2002 issues of Cruising World magazine

The book "Self-Steering Under Sail" by Peter Christian Forthmann is available for free as a 7.5 MB PDF file from the Windpilot web site.

Manufacturers and models:
Cape Horn
Chrono Vane
Holland Windvane (Bouvaan)
Mister Vee (for smaller boats)
Homemade windvane
Voyager Windvanes

From John Chandler on Cruising World message board:
A windvane is a blessing on a boat, particularly if short-handed and even more so going to windward. A good windvane on a well-balanced boat will sail closehauled with more sensitivity than all but the very best helmsmen - and for a lot longer - thus making the sailing more efficient. True, they are not cheap, but it is an investment that will repay itself in comfort and satisfaction many times over.

Wind-vanes don't work well in light and/or variable winds, and not at all when motoring.

From John Dunsmoor:
Wind-vanes really only do a good job going upwind, where the apparent wind is pretty good. And since wind-vanes follow the wind they work best when either the wind is consistent in direction or you have enough sea room where shifting heading 20 degrees will not put you in danger. Coastal cruising the east coast and Bahamas fits neither of these requirements. Also you have the problem of consuming the transom with gear using a standard servo-pendulum steering system, which is a major pain and ripe for disaster from docking or other boats.

I am not a fan of wind-vanes. I am a fan of electric autopilots that do their job very well. If power is a problem then I would suggest solar panels or maybe a wind charger. There is an adapter for a wind-vane sensor to add to an autopilot.

From Erik Hammarlund on Cruising World message board:
Ain't NO SUCH THING as the 'best' vane for every boat, every condition, every owner ...

All the good servopendulum vanes (Monitor, Cape Horn, Fleming, Windpilot, etc) use the same principle to function and differ quite a bit in appearance. Have a transom with a difficult attachment, or want to be able to easily use your vane as an emergency ladder? Try a Monitor. Would you rather drill one big transom hole than many small mounting holes, or do you want to avoid cockpit lines? Consider a Cape Horn. And so it goes. Me: I have a Monitor. My friends have a Cape Horn on their sistership (works great) and another couple of friends have a Fleming. And that's just touching the surface of the iceberg; I haven't even mentioned the non-servopendulum designs which are best for a smaller section of boating.

So first decide what's most important -- light air performance, lack of line in the cockpit, ease of repair (globally? locally?), construction material. Choose how you are able to mount it (they all mount with slight differences) and that will eliminate one or two. Some simply may not fit for other reasons -- you may not easily be able to rig a wheel-steering Monitor on some center cockpits, for instance ... or a Cape Horn if you don't have plenty of room near your quadrant.

There is no best. Except for the one *I* own, of course ... ;)

We have a Hydrovane [wind-vane], which has its own rudder, so it requires no connection to the main rudder or steering gear. After all, there are already enough lines in the cockpit! It has a remote course change line which allows steering from the companionway in heavy weather. It's a clean install (one vertical shaft) rather than the "jungle gym" look of the Monitor and others.

From Rufus Laggren on IRBS live-aboard mailing list:
I understand hydraulics to be a very reliable, though not commonly used, system. The disadvantages include no feedback to the helm, high initial cost, and the relative difficulty of hooking up a purely mechanical windvane, and the need to be in a moderate size town to get service; depending on the installation jury rigs may be difficult. Advantages include tremendous mechanical advantage between helm and rudder (no strength needed to man the helm), very low maintenance on properly installed systems (not *no* maintenance), ease of placing the helm at any location and also of adding 2nd or 3rd helm stations, ease and reliability of autopilot installations. The technology is very mature and common throughout the world and parts and expertise are readily available anywhere you find industry, agriculture, or heavy construction.

The logical way to go with hydraulic steering is the Saye's Rig [windvane]. I think it's the most rugged and sensible windvane - it drives the rudder directly with a trim tab, which means as long as you have a rudder attached, you're steering! With most of the other systems, you're dependent on the connection to the steering wheel, the chain or cable to the rudder quadrant, the shaft to the rudder, etc. - in other words, an awful lot of points of failure.

From Lee Huddleston on The Live-Aboard List:
A couple of years ago I contacted Scanmar about windvanes. As you probably know, they have purchased the rights to sell several different brands and versions. When I told them that I had a center cockpit and hydraulic steering, they recommended a Sayes Rig.

The Sayes Rig has no lines to the cockpit because it controls the rudder directly. A long metal loop is attached to the rudder. The loop sticks out behind the rudder. A servo pendulum paddle hangs down through the loop. When the wind shifts it turns the paddle. The water then causes the paddle to deflect to the side. Since the rudder is attached to the paddle by the metal loop, the rudder is deflected to the side as well. Of course, the hydraulic ram on the rudder has to be deactivated to let the rudder swing.

It seemed to have the advantage of being exceptionally simple and direct. It appears to be susceptible to adding a small, electric autopilot in place of the windvane portion so that an autopilot could be rigged at considerably less expense than a below-deck version. And, finally, it looks like it could be adapted for an emergency tiller arrangement.

From Tom Plesha on IRBS live-aboard mailing list:
... Personal experience has shown that windvanes don't work when you have to motor (not enough wind). ... My B&G hydraulic autopilot works in high wind, low wind, no wind, big seas, no seas, broken steering cables, broken quadrant, etc.

From Erik Hammarlund on Cruising World message board:
The general consensus is Cape Horn wind vanes are good, solid performers -- nice units. Between Cape Horn, Monitor (my choice), Aries, and Fleming is a pretty even choice. Haven't really heard any Cape Horn complaints yet (barring the hole in the stern ... scary to drill :)

From Rick Kennerly on the WorldCruising mailing list 12/2000:
The Westsail Owners Assn did a group buy of 15 Cape Horns last year. Installed most of them on 32s, but a few on 42/43s. Everyone is extremely pleased with them.

From RyanN on Cruising World message board:
I picked the Sailomat for reasons that I feel make it the best choice for me. These very well may not be the same reasons others use for their selection. Features that I like about the Sailomat are:

- Easy to Mount. It took me about an hour to drill the four holes in my transom and bolt it on.

- Easy to remove. I can remove the rudder and vane in about a minute. The rest of the windvane can be removed by one person with one bolt and put below or in storage. This should keep the equipment looking new.

- No custom parts. I'm the second owner, but first person to use this specific unit. No custom parts makes resale much easier. If I had bought a monitor or flemming, there would be a significant expense in having a new custom designed and fabricated mounting. A Cape Horn is really for life. If the boat's next owner doesn't want the wind vane it should be easy to sell.

- If the price and situation had been right, I would have considered a windpilot which is very similar to the sailomat.

From Ray Thackeray on the WorldCruising mailing list:
[For center cockpit boat with dual-station hydraulic steering:]

The Saye's Rig is probably your best option - especially with hydraulic steering. I personally think it's the best design of them all, mainly because of the following reasons:

1) If the steering system totally fails, as long as the rudder is still attached you can steer with the Saye's Rig.
2) A very clean and simple mounting.
3) Rugged as all hell.
4) Provides huge steering power (trim tab on long lever arm).
5) Simple overall design - almost NOTHING to go wrong.

From John / Truelove on the WorldCruising mailing list:
Suggest you look at the Hydrovane from England. I installed one on my Westsail 43 four years ago and I love it. It's highly rated in the SSCA survey and seems to be the favorite of European cruisers. The remote control, lack of lines in the cockpit, no connection to the wheel and the fact that it can function as an emergency rudder are all plusses.

From Ed Pare' on The Live-Aboard List:
I "shopped around" extensively, even talked to three manufacturers before buying Scanmar's Monitor. My reasons were that it had the strongest installation of any available, and that the unit was used on more boats than any other. They only make one servo-pendulum unit and vary the supporting framework and length of safety tube to suit the boat. This, to me, makes more sense as one can get the same part shipped to him in case of failure.

I was surprised I had to hacksaw through 4 SS tubes but it wasn't an insurmountable difficulty. The most inexplicable part was trying to "invent" a way to hold the spacers in the tubes before bolting the whole thing together. It turned out not to be an issue as the tubes had been "squished" a little when I shortened them. Installation was a few hour's work with the boat backed up to the dock. You will need a sharp hacksaw to shorten the mounting tubes, a large file or bench grinder to fit the spacers, and a powerful hand drill (to go through 1/16" SS). You have to drill all holes while the unit is being held to the boat with lines.

After I read how to use it, it actually worked perfectly the first time - no learning curve.

It's limitations are that it takes .25 to .5 knots of boat speed from increased drag and that the lines to the wheel take some cockpit space.

Ongoing maintenance consists of spraying with fresh water when memory serves.

From Charles Cohen on the Morgan mailing list:
> How do you install a vane to work on a hydraulic steering system ?

This is a nasty problem (I have an OI 36 with hydraulic steering, and I sympathize). It's not a short answer -- sorry.

There are three ways to do it:

1. Connect the windvane and its servo-blade to the ship's rudder mechanically, and either:

1a) disconnect the rudder-actuation hydraulic cylinder mechanically from from the rudder (else, it'll stop the rudder from turning) or

1b) short-circuit the rudder-actuation hydraulic cylinder with a valve.

The "Saye's Rig" is an example of (1b) -- it links the servo-blade to the rudder underwater, with the servo-blade inside a long hairpin off the aft edge of the rudder. It's available from Scanmar, who also make the "Monitor" (Aries-type) system.

A technician from Hynautic told me that he had worked out the loads on a rudder, and he would never use a mechanical disconnect -- too much chance of crushed body parts.

The hydraulic short-circuit is effective and simple, but it leaves you with hydraulic-cylinder drag in the system. Probably OK, except in light air.

2. Use the windvane (and possible servo-blade) to control a second (auxiliary) rudder. FWIW, I just bought an auxiliary rudder, hoping to modify it for my OI 36. If you want diagrams for this setup, they're in John Letcher's "Self-Steering for Sailing Craft".

With an Aries, you'll have to decide where to position the aux rudder to not interfere with the Aries servo-blade.

Scanmar will also sell you an auxiliary rudder for the "Monitor", if you want to use that. And the Windpilot (from Germany, I think) has an auxiliary rudder option.

3. Put a hydraulic pump into the water, put a small propellor on it, and use the windvane to control a hydraulic valve which connects that pump output to the boat's hydraulic steering system. This is available commercially as the "Windhunter", I think. It's not simple (above-deck hydraulic lines make me nervous), and I think that Nigel Calder couldn't get it to work on his boat. The idea is intriguing, though.

There's no simple solution that I know of.

My situation:
I have a heavy, center-cockpit boat with hydraulic steering and a stern platform and dinghy davits on the stern. And a long mizzen-boom swings out over the stern, just past the transom. How can I get wind-vane steering ?

Any kind of linkage between vane and servo-pendulum rudder would be blocked by the stern platform and dinghy. Trim tabs on the main rudder wouldn't be powerful enough.

What I'd like:
  • Wind-vane that controls a hydraulic valve.
  • Hydraulic pressure provided by a pump with power-take-off from the propeller shaft (which turns while sailing or motoring).

I sent out this message:
I am starting to think about adding wind-vane steering to my Gulfstar 44. It has center cockpit, hydraulic steering, stern platform, stern davits. So, many of the existing servo-pendulum products don't seem a good fit for it.

Most of my attempts to think up a custom solution come down to this:
How can I generate hydraulic pressure while sailing ?
I'd have a vane connected to a valve which routes this pressure to the steering.

I can think of two solutions to generate pressure:
1- tow a propeller
2- power take-off from the freewheeling propeller shaft

Are there any other ways ? Would these ways generate enough pressure to steer with ?

[The only similar systems I've heard of are the "waterdrive" and the "Windhunter", and both of their suppliers seem to be out of business (I could be wrong).]

From Ernie Martin on the SailNet liveaboard-list:
The first problem you have with hydraulics is when the pump is turning you have flow. You must do something with that flow, save it in a accumulator tank, run it in a motor, or return it to the reservoir tank. To just turn off the pump would lock up the shaft that drives it. The system must be tailored for the job you don't want any extra from the pump and you dont want to be short or the job is not done. Tailoring the system means calculating the pump displacement to match the motor or cylinders volume needed to do the job and at what pressure and flow. If you try to get the needed power from a free-wheeling prop the RPM will change with boat speed and your steering will be erratic. You could put a regulator valve in the supply side but that only works when there is a surplus. As you add new components to help save the surplus or regulate the over-flow you compound the complexity and the cost of the system. It will be different for each boat I'm sure if it could be done as a kit to add on to any steering system someone would be there to sell it to you. I know of no such kit. Good luck but my recommendation is to keep to the systems that are out there or at least copy a proven system.

From jefframage on the SailNet liveaboard-list:
This system will require one of two things, a really good hydraulic/marine power designer, or a lot of trial and error.

It can be done, and I understand your desire to make it work.

The issue is really one of efficiencies ... the system driving propeller is let's say 80% efficient, the pump being driven by the prop is going to be about 85% or a little more, then there are the losses in the plumbing, then the motor on the drive system.

Then the biggest issue is energy storage ... in hydraulics it's called the accumulator ... how much storage will be needed for the quick actions of the steering as a following wave will crest under the boat, etc, etc.

Or will the system be used to drive a "trim tab" on the following edge of the rudder, effectively back driving the rudder and wheel ... much like the wind driven systems ? This would take a whole lot less energy than driving the entire rudder.

Could something like this work? If yes, it might be able to run off the existing hydraulic system, but use significantly less power.


Have you looked at the all-electric drive for sailboats, with regeneration underway via a back-driving propeller? You might be able to use that technology too.

From John Dunsmoor:
... Here are the pitfalls [of power take-off from a free-wheeling propeller shaft]. First if you have a hydraulic transmission then you have to determine if there will be damage to this unit by free-wheeling ? Second you have a standard cutless bearing and do you wish to use this up and possible damage the shaft with all this rotation ? Third is the cost more than the benefit ? ...

From Bob at Paradise Connections Yacht Charters:
I could design a hydraulic system for you but it would be very expensive and not work as well as an off-the-shelf auxiliary rudder system. For your type of boat a standard system like the Autohelm by Scanmar or the Windpilot would be excellent. There are several big disadvantages to the type of Windvane/Hydraulic rig you are thinking of. I have personal experience with the British Windhunter system and the main disadvantage is that it did not work well below five knots and quit working entirely at three knots. The various windpilots available will all steer you as long as you have wind for your sails. The other disadvantages are it is a much more complicated system and repairs are not in the realm of normal boat folk without access to a machine shop ... after many years of cruising I have always erred on the simple easy to fix gear ... When we lost our self steering off the Cape Verde Islands due to a weld failure I was able to repair it with simple hand tools 300 miles from the nearest land in nine foot seas ... Would have preferred to avoided the experience but it does show why a simple mechanical system is the best way to go.

The big plus for both of those systems is that they improve your balance and you can use your main rudder to perfectly trim your boat and then the windvane system is 100% more effective. Another option is the addition of an small electronic tiller pilot to actuate the vane if you want to also have the ability to steer a compass course as opposed to wind (this type of hybrid outperforms even the most expensive electronic autopilots).

From Greg Kruegermann at Windpilot:
Forget the hydraulic idea, a system called "Windhunter" tried this and failed to get any reasonable results. They folded and left many angry customers out thousands of $$ with only a pile of junk to show for it. The ONLY way is with an auxiliary rudder. Forget any bypass system since any rudder movement still needs to push hydraulic fluid around.


When comparing a hydraulic "Windhunter" system keep this in mind:
1. The ability of the hydraulic pump to supply effective and continuous pressure and the period over which this pressure can be maintained.
2. The drag of the generator.
3. The quality of the steering signals given by the transducers.
4. The availability of automotive/adaptable components.
5. The technical aptitude of the owner AND crew in fitting the system as well as qualified service people.
6. The ease with which manual steering can be restored during an emergency.
7. The total price of a one-off hybrid system compared to others.

Windhunter's complaints and problems covered ALL points. All also complained of oil leaks/mess.

Technically they had key engineering problems in all components like the ram itself and wind-vane.

Peter Foerthmann owner/engineer of Windpilot is the only person in the world very familiar with even the finest details of this type of system. If there was a steering solution using hydraulics in this fashion he would make it! In my discussions with him over this, his only answer is ... (say it with a German accent) FOUR GET IT!

From Greg Davids at Sailomat:
You've got a bit of a tough situation. I personally would not bother with trying to generate hydraulic pressure while sailing. A company called Windhunter spent many, many thousands of dollars trying to develop just such a design. They came out with a design that was based on towing a propeller to generate the hydraulic power. Quite frankly it never worked very well, and they left many customers in a lurch. They finally went out of business a couple years ago.

As an aside, having your boat's main propeller free-wheel is generally a bad idea. My understanding is that it is usually harmful to the transmission, and it adds extra drag (which I know is counter-intuitive). ...

My situation, again:
I have a heavy, center-cockpit boat with hydraulic steering and a stern platform and dinghy davits on the stern. How can I get wind-vane steering ?

Idea: an air-vane connected to a water-vane which then drives the hub of a hydraulic steering wheel. The air-vane senses the wind and rotates the water-vane. The water rushing past the water-vane thrusts it to one side. The rotation to the side drives the pump-hub, which is connected to the hydraulic steering as just another steering station.

  • Air-vane: board on top of vertical shaft. Shaft must be mounted with bearings to reduce friction.
  • Water-vane: rudder-shaped board on bottom of vertical shaft. Shaft must be mounted with bearings to reduce friction.
  • Linkage from air-vane to water-vane: lines attached to horizontal arms attached to the vertical shafts. Arms must be attached to water-vane near center of horizontal pivot, to minimize twisting as water-vane tilts sideways.
  • Bearings for water-vane vertical shaft are mounted on a plate, which is mounted on the end of a horizontal shaft that goes through the transom. Other end of that shaft has a fan-belt (or chain) pulley on it.
  • Fan-belt leads to pulley on steering hub (pumps). Pulley on water-vane is larger than pulley on steering hub.
  • Need easy way to remove water-vane, for motoring.
  • If remove water-vane, and add rod up to deck-level, rod will serve as emergency steering if main steering station fails.
  • On my boat, water-vane mounting must pierce or avoid swim-platform and dinghy on davits.
  • Want place where horizontal shaft from water-vane pierces transom to be as high above waterline as possible.
  • Need hydraulic valves to add second steering station (well-known situation).
  • Want water-vane near centerline. On my boat, air-vane must be tall or far to side, to get away from wind-shadow of pilothouse. On my boat, hydraulics are on port side of stern.

From Magnus Perman on World-Cruising mailing list:
Re: hydraulic steering + wind vane:

IMHO there is no way of getting the (sensitive) vane gear to operate via the (very heavy resistance of) hydraulic steering.

On my boat I do have both though. The solution is that the hydraulic system has a by-pass valve to open when I want to use vane steering. The vane then operates on the (emergency) tiller. My boat is a ketch and due to the mizzen boom, I have to angle the vane 45 degrees aft. Works a treat anyway.

Of course there are vanes that operates on the wheel (or quadrant too) - the solution is the by-pass valve.

From Paul on Cruising World message board:
Re: home-built wind vanes:

Built one ... once ... horizontal axis vane, direct coupled to the tiller. No servo trim tab. NG not powerful enuff. Used SS and aluminum. Maybe $100 spent. If I built one again, I'd copy Scanmar Marine's 'Autohelm' horizontal axis vane coupled to a trim tab on an auxiliary rudder. All parts easily built. Can actually buy the vane only, and make your own rudder (or couple to ship's rudder if transom-hung).

From "Offshore Cruising Encyclopedia" (1989) by Steve and Linda Dashew:
"If you're on a tight budget, don't be afraid to try making a vane on your own. Probably half the people we've met around the world have done it ..."

Build trim-tab self-steering: Sarana's "Self-Steering Gear"

From article by Evans Starzinger in 1/2004 issue of Cruising World magazine:
  • Clean windvane carefully before long passages; want action as smooth and friction-free as possible.

  • If it uses lines, invest in low-stretch and low-chafe rope.

  • Don't leave wind-vane or auxiliary rudder in water while motoring: the propeller wash causes huge vibrations.

From Len den Besten on World-Cruising mailing list:
I found this info on and translated the essentials of the original german text:

"Sailing the ITC we had to think of something to deal with the fact our windvane doesn't function under 5 knots of wind. We simply attached a plastic bag at the top of the vane so the weak wind flows in and fills it like a parachute. This "parachute" is capable of moving the vane when the wind itself is not. Because of the light weight of the bag there is no need to alter the contra-weight of the vane. At the bottom corner, the bag needs a hole so the rain can't cause a heavy bag of water. We also used the plastic bag with stronger winds because it made the steering installation more sensitive and faster in response. The result is a less zigzag course. It might be a good idea to design a windvane with some sort of "windcatcher" at the top of the vane.

We used this method everywhere and with success. We didn't use it when sailing the Indian Ocean, cause there's plenty of wind. The windvane normally starts functioning well at 5 knots apparent wind but with this adaption it starts at 3 knots. Under those circumstances the speed suffices to move the rudder-pendulum-arm adequately. This setup was valuable especially on downwind course in the Intertropical Convergence Zone."

Credit to Siggi and Jurgen and their dog Julie, S/v Petit Prince.


  • Tiller pilot: simple, limited power, exposed to elements, bad reliability record.

  • Wheel pilot: simple, moderate reliability.

  • Belowdecks: more powerful, protected from elements.

    • Linear drive: can be electrical or hydraulic.

    • Hydraulic: easy to install on hydraulic steering.

    • Rotary: least common.

  • Auto-pilot connected to windvane: smarts of auto-pilot, power of windvane.
Hydraulic consumes the most power if constantly running.

SailNet - Tom Wood's "Autopilot Overview"
SailNet - Sue and Larry's "Choosing an Autopilot"
West Marine's "Selecting an Autopilot"
Burnet Landreth's "Making Autopilot Work"
Tillerpilots tested in 1/1/2001 issue of Practical Sailor.

From Jerald King on Cruising World message board:
... Installation is critical. A well-thought-out and well-executed installation is mandatory. One of the boats I sailed had a near catastrophic failure of a very expensive Robertson/Whitlock autopilot. After 24 hours of careful study it was obvious that the problem was due to the mounting bracket fabricated by the installers. The near-failure had nothing to do with the electronics or electrics.

Maintenance is essential. The undersized ST4000 on my brother's Tartan 42 works well IF it is properly cleaned and reassembled every 50 hours. The autopilot will constantly disengage if that maintenance is not done.

Mainsail trim is critical. My Caliber 40 develops a lot, 15 - 20 degrees of rudder, of weather helm when there is too much main up. That amount of weather helm causes the ST6000 to work way too hard and way too often. An early reef, and an eased mainsheet lets the ST6000 work at about 1/4 the effort with almost no loss in boat speed.

The ST4000 on the Tartan 42 can't steer in 15 knots apparent if the main is trimmed the way we would like it when hand steering for max speed. However, if we ease the sheet and/or reef the main the ST4000 does a good job of steering in 15 knots apparent with up to 5' seas.

If you trim the sails for max speed you may be overworking the autopilot drive unit and thus causing premature wear. If you want to go for max speed - hand steer the boat. ...

From Mark Mech on IRBS live-aboard mailing list:
I have a friend at West Marine and he told me that the tiller type or smaller wheel type autopilots generally won't even make it down the West Coast without breaking. This is somewhat due to people getting the smallest size necessary when they should jump up 2 sizes for serious cruising. An alternative is to set the cruise control up so that it is controlling a trim tab or servo tab on the rudder or the autohelm servo blade. This takes almost no effort to control and will put very little wear on the autohelm. ... He also said that any of the units under $3000 are really just for day use, not for serious offshore use.

From Rufus Laggren on IRBS live-aboard mailing list:
... Autohelm "tiller" pilots are considered "consumables" based on past and present performance - bring a half dozen or so and you can entertain yourself mixing and matching parts to get at least one to work. But many sailors use them just this way because they are so (relatively) cheap.

From Dennis / True Mettle on Yacht-L mailing list:
Maybe I had a lemon but my Autohelm 1000 was one of the highest failure rate systems I own. If I did not have a soldering iron on board (and some electronic smarts) it would have been thrown over the side after about the 10th failure. I originally brought it into our "reputable" Autohelm dealer, was billed like I printed my own money and had it fail the very next trip. It finally stripped the gear on the motor shaft which forced me to retire it. Almost everyone I know who carries this unit, has a spare. I drove a well balanced Newport 28 with this unit.

I will not buy Autohelm again ...

From Lew Hodgett on Yacht-L mailing list:
Maybe the Autohelm 1000 wasn't designed to handle my 7,500 lb, 30 ft, tillered boat, but IMHO, the A1000 was a piece of equipment, that as a manufacturers representative, I'm glad I didn't represent.

It was IMHO, not a very reliable piece of equipment.

After it crapped out twice in the same season, got Autohelm to eat it on exchange for a larger unit which also had it's problems, but that is another story.

I would treat any "push-pull" type electric autopilot as a piece of throw away consumer electronics.

If it dies, forget about it and get a backup unit out of the locker.

If it works, you are ahead of the game.

From Eppo Kooi on Yacht-L mailing list:
I have never had any problem with an Autohelm 1000. I have been using one for many years (almost ten years I think) in all kinds of weather: heavy rain, strong winds, both inlands on fresh water and out on the sea on salt water. The Autohelm has not been installed as prescribed in the manual, but a bit more forward on the tiller. In this way the forces to be exerted by the Autohelm are smaller. However at the cost of speed of change. I found the behaviour of the boat more quiet that way.
From Tony Cabot on Yacht-L mailing list:
I would have to agree with Eppo. I have had an Autohelm 1000 on my F27 for 8+ years and have had no problems. The unit is used mainly for motoring and singlehanding. The tacking function makes singlehanded tacking and gybing less of a chinese fire drill. It seems to make lots of tiny corrections but nothing as excessive as some have mentioned. One reason for my success might well be the well-balanced and light helm of the F27 on most points of sail.

From Felix U on Cruising World message board:
My boat came with an Autohelm 4000. The system has broken down more than any other system on the boat. It's broken down more than the combination of the top-five breakdown-prone systems -- combined. If you stay with this, make sure you're heavily overstocked with replacement parts.
From Laurie on Cruising World message board:
I've used my ST4000 for about a thousand miles now and love it.
From Brian Woloshin on Cruising World message board:
Autohelm 4000's do not stand up to the rigors of open water passages. I do not own one but I traveled in the company of two boats that did. One was an Alpa 31 (Italian) that went through two drives in a few months. Both drives failed the same way, the cases split open and disgorged all the bogey wheels. The other boat was a Niagra 35 and they had similar experiences. Both boats are well within the recommended size for the 4000. The drives are not tough enough to stand up in strong downwind and quartering seas (tradewind) sailing.
From ROwen on Cruising World message board:
Me too!! - would never use another 4000. We fought with ours for 3 years, and it never did work for more than a month at a time. Problems: belts, motors, controllers.
From Ron on Cruising World message board:
Re: Autohelm 4000, I have one on my Pretorian 35 and it is worthless in all but motoring in glass-like conditions.

Several people complain of bad service from Raytheon (owner of Autohelm). And apparently they don't publish Autohelm wiring diagrams, so all repairs require buying new parts.

From article by Evans Starzinger in 1/2004 issue of Cruising World magazine:
Auto-pilot reliability is greatly improved by installing below-decks or inside a dodger or pilothouse. Many failures are water-related.

From Ralph Ahseln on Yacht-L mailing list:
I can give you a "small boat" experience. I had a Catalina 22 and I got a Navico TP-5000 (5 or 6 years ago). I loved it so much I took it and installed it on my current C27.

I chose the Navico because its power requirement (at rest) was much lower than the Autohelm. In fact it uses very little even when active. The Navico "Hardover" time was much slower than an Autohelm ... but that was not too much of a problem for me. I have used it over a 9 hour period of time and it is on its 5th year. ...

The bad news ... Downwind in a following sea. It overcorrects and "works" so much I turn it off and I hand the tiller. I suppose it would be ok to run but I hate the sound of the motor ... Zizzz Zizzzzzzz Ziz Zizzzzzzz Ziz Etc. also the owners manual says NOT to use it downwind. Remember most of these have plastic gears.

If you are considering one ... Hint ... Get the biggest/powerful one you can afford ... Not only less chance of trouble ... but like me ... you may take it with you when you go UP to a bigger boat.

From Mark Anderson on Yacht-L mailing list:
I also have the Navico TP-5000 on my Pearson 30. I'm very pleased with it. I've never figured out why it makes quick little corrections even when motoring straight in calm water. The tiller moves a few inches and then back in just a few seconds. The back and forth is before the boat even has a chance to respond and isn't off course anyway. Oh well. It steers a straight line.


My dissatisfaction is with the windvane addition. There's frequently too much overcorrection. So, I rarely use it. Generally no problem with sailing or motoring to a compass course. Downwind use has also been acceptable.

No malfunctions or maintenance problems. I occasionally put vaseline or lanolin on the shaft. The motor makes some growling noises when under heavy load, but it keeps on going.

Oh yeah, the other problem. In rough water, occasionally the tiller may jump and the pushrod acts to raise up the tiller, (it is installed strictly horizontal). When this happens the tiller goes way up and the pushrod pops off. Solution? Hang a weight from the tiller in those conditions. ...

From John / Truelove on the WorldCruising mailing list:
BWS did a comparison of below-decks pilots a couple of years ago. Their top picks were Robertson and W-H, as I recall.

I would not use anything but a true hydraulic system - stay away from the worm gear stuff. It just isn't heavy enough, IMHO.

We installed a Robertson (Simrad) with the AP20 control head 2 yrs ago and have had no problems. The major piece is the ram/quadrant config.- otherwise, install is "cake". The actual hydraulic system is made for Robertson by Hynautic and is very good gear.

If you decide on Robertson, suggest you communicate directly with them directly (425-778-8221) for sizing, even if you buy thru a dealer (you may have to) ...

From Vic Hatami:
I have had the Robertson AP 200 and AP 300. Always had problems with this product. Board, compass, pump motor. How do these people stay in business ? Why do they stay in business ?

From Dave C. on Cruising World message board:
I've had a CPT autopilot since '97. Installation was a bitch. It has always been baulky, but when it works it is great. Usual scenario is that it will work for a few hours, then go haywire. I turn it off, then after an hour or so hand steering, try it again, and it works fine for another few hours. Someone told me that's because it overheats. He said he installed heat-sinks on his somehow and solved the problem. There may be something to that theory because it has always worked great at night when it is cooler. I use it a lot more than my Aries vane.

From Slipf18 on Cruising World message board:
Had a CPT autopilot for years. When it works it works well. When it breaks, have plenty of money ready: their repair philosophy is "charge a ridiculous amount of money and if you don't like it, take a hike ..."

From John Branch on the Morgan mailing list:
I stayed away from autopilot systems that plumb into the existing hydraulics. I settled on a Brookes and Gatehouse system that is totally independent of the existing system and has a separate hydraulic ram [and integral pump] to connect to the rudder shaft. My theory is that if the main system fails I'll be able to use the autopilot to steer by using the left and right buttons on the control head.

From Paul Olson on SailNet's Gulfstar mailing list:
I just costed out a Simrad AP21 to replace the Centec Benmar that was installed on my Gulfstar 44. I will keep the hydraulic motor of the old system. The compass, brain, rudder location device amount to $2780 with dealer discount. He estimated 8 hours for installation. Plus a sea trial. ...
From Keith on SailNet's Gulfstar mailing list:
We replaced the original autopilot on our 43' ketch with a Simrad AP21. Although keeping the old drive unit was an option, we chose to replace that as well as the newer unit uses significantly less energy than the Benmar drive. During a trans-Pacific cruise of 19 days, the first five of which were in gale force winds (35-50 kt), this Simrad performed flawlessly. It is the best investment we ever put into our boat. Installed, the AP21 ran about $5k.

PS: If we were going to do it all over again, we would opt for the gyro compass instead of the fluxgate. There was some consensus that the gyro performs better in heavy seas as it "thinks faster" than the fluxgate.

From Dave Zatarain on SailNet's Ranger mailing list:
Re: Wheelpilots:

This year [2005] I installed a Simrad WP10, which is essentially a WP32 less the remote capability. In regards to function, it has worked outstanding. I am amazed just how well it works. There are a few things to consider:

1) The first unit I received had an occasional problem with the belt sticking, even though the clutch was disengaged. Simrad swapped out the unit and I have not had this problem with the second unit.

2) If you have an Atomic 4, the shift handle on the Edson pedestal probably exits the aft section of the pedestal then has a 90 degree turn to the port side. This handle will interfere with the clutch housing. Simrad offers a replacement handle that has an offset to avoid the clutch housing.

3) The reason I selected the Simrad is that it is self-contained and I felt that the installation would be easier and also I could remove it easier if desired, although in reality I leave it on and made a sunbrella cover for the wheel. Also, I did not see a convenient way to mount the RayMarine control panel display to the pedestal. The WP10 control is integral to the device.

4) The thing I liked about the Simrad the most (control panel being integral) ended up being the only real drawback for my installation and probably on other R33s. The control panel extends to starboard. Since my wheel is 24" diameter, the control panel extends about 2-3 inches beyond my wheel. This becomes a minor obstruction that I have adjusted to. However, the big problem is that there is minimal clearance between the forward edge of the wheel and the control panel, so when you are steering the boat, you fingers may get pinched. This may not be a problem for pedestals that have shifting on the side, as the A4 shift arm may be eating up the fore/aft space.

5) I ended up making a plastic wedge to mount between the control panel and the pilot so as to increase the gap between the wheel and the control panel. On wheels larger than 30", this interference is probably not a problem.

6) Again, I would like to say that the WP10 performs excellent. I can't believe I have lived this long without one as I sail my boat by myself about 50% of the time.


The WP10 is very easy to install and remove. Once the pedestal bracket has been mounted, to install the WP10, remove the wheel, slide the WP10 into the bracket, put the wheel back on and clip on the WP10 badge that holds it onto the wheel spoke. It takes about 60 seconds to install and remove. I have a power cable run through the deck next to the pedestal with a two-pole plug similar to a trailer light connection.

If you go with a WP30/32, you will need more poles on your plug for the communication wiring for the remote.
From B. Courson on SailNet's Ranger mailing list:
I have a Simrad on my R33 and this is the third season. Works like a charm ... installs and uninstalls easily. The remote is great! I have it below at the nav station and have used it to steer the boat during thunderstorms ... with GPS, radar, and the remote you only need to go on deck for visual observations ... between lightning bolts!

I would go with the Simrad ... if mine died for some reason I would go right out and buy another ... does very well in most conditions due to the programmers using "fuzzy logic."
From Andrew Rooney 10/2006:
... We took our non-functioning Simrad Wheel Pilot into a local dealership [in Trinidad] for repairs, only to find out it needed a new circuit board and some mechanical repairs which would have cost $3100 TT (or about $600 Canadian). We decided not to do the repairs and to garbage the unit, as we have not been happy with its reliability and have had several major repairs done since we bought it in 2001. That repair would be over half the price of a new one. ...

From Greg Hanka on the IRBS live-aboard mailing list:
One thing I have learned about auto-pilots ... if you install a full-blown autopilot as has been discussed, make sure that your system has a handheld remote control available which will allow you to make course corrections without walking all the way back/forward/up/down/over to the helm. We sailed for eight months putting up with that minor hassle, and now that we've put in a Seatalk jack and bought the remote, there is no going back. With it we can all lay up on the trampolines and control the boat from there, or from any stateroom in bed while cruising, or wherever. This is an easily overlooked feature whose true value is not fully realized until after you've had one for a while. Talk about your heroic level of convenience, especially if you are like me and spend most of your time sailing in a very large but very busy bay, in which you will want an autopilot but also want to make frequent course adjustments.

From Peter Hendrick:
Among things that we specifically avoided based upon 1st year experience:
Large autopilot (we believe they work well in light winds or while motoring; they also make noise, require maintenance and drain the battery).

From John / Truelove on the WorldCruising mailing list:
... No matter who does the auto-pilot install, insist on shielded power cables throughout; don't be talked out of it by the dealer. This is the key to heading off problems with AP noise in your SSB as well as the SSB knocking the AP out of "auto" when you xmit.

From Charles Cohen on the Morgan mailing list:
Most autopilots are sensitive to "bad power" -- that is, transients on the DC feed.

Recommended to me as a good repair place: Heinz Marine Electronics in Ft Myers Beach FL.

See my How to Make a GPS-Based Autopilot Control Head page.

From Ignas de Grefte:

I am always sailing my old fishing cutter alone. When handling the sails I often have to run back to the rudder in order to steer the bow again straight into the wind.

My first idea was to use the GPS, but
- using the built-in GPS-simulator it looked like the data-changes were too slow and
- first you have to establish the course of the wind, enter it's complement into the GPS etc.

So last winter I designed a system steered directly by a windvane. This summer the trials were run, and modifications were made.

Although with a ketch-rig the boat stays pretty well on course, hooking up the GPS to the steering system is the next logical step. All I needed was a hardware-NMEA-decoder. I spend quite some time on Internet, but did not find anything suitable until I saw your article with the reference to the Smart Coupler. Which seems rather expensive.

My project:

A gap in a disc, mounted on the shaft of the windvane, and revolving inside 2 phototransistors, determines if the rudder should go to starboard or portside.

A potentiometer, connected to the steering wheel, not only gives the position of the rudder, but is also hooked-up to a circuit, which can change the range of the rudder. This can be done by hand, depending on the weather conditions.

2 pushbuttons and a rudder-indicator near the foremast allow distance control.

The ruddermotor is driven by a bridge (3 amp), which rotates it cw or ccw.

The gearbox has a ratio of 1:1000, so a small motor can do all the work. It draws 1 amp with 24V.

The electronics consist of:
2 ea CNY-37 phototransistors
1 ea LM339 quad comparator
1 ea 74HC08 quad AND-gate
1 ea L298 dual drive bridge
1 ea TLC272 dual op amp
1 ea MC78to5 5V regulator
1 ea relay, potmeter, zenerdiode. resistors and capacitors etc
All soldered point to point on a board of 10x15 cm.

Your project:

What you seem to need is a drive bridge like the L298, but stronger (or put two L298 in parallel). One input drives the motor CW, and the other input reverses the output to CCW. If both inputs are the same, the motor stops. These inputs can be connected to a NMEA-decoder/reader/capturer/coupler/interface, whatever the name. The bridge has a sense-output and enable-input, which together can be used to limit the starting and maximum motor-current.

It is over 30 years, that I did something with an Assembler language and BASIC. I am more of a hardwareman, and I don't fancy learning an instruction set of a microprocessor, just for one item out of a project.

Auto-Pilot driving Windvane

Auto-pilot is the controller; it attaches where the "vane" of the wind-vane attaches; the mechanical power of the windvane drives the rudder. So you get the benefits of an auto-pilot (can use down-wind and motoring; holds a compass source regardless of wind-shifts) and the benefits of a windvane (free power; simpler drive mechanism).

One problem: windvane mechanisms aren't designed to deal with propeller-wash, since you don't usually use them while motoring. This may cause increased wear on the windvane mechanism.

"Automating a Windvane" (auto-pilot to windvane) article by Terry Sargent in Sep/Oct 2000 issue of Ocean Navigator magazine

From Rick on WorldCruising mailing list:
Several people have protected their tiller pilot by mounting them in the lazerette and running a flexible cable to the air vane section of their windvane (gear shift or throttle). The loads are low, the response times excellent (although limited by your cable throw). Reliability has gone up considerably.

From Eric on WorldCruising mailing list:
I'm planning to use the Cape Horn partially because I can hook up the tiller pilot inside the boat instead of out in the elements - the least powerful is quite fine, as it is not actually turning the steering quadrant, the servo is doing that. As it's the elements that cause the above-deck pilots to fail so quickly, one ends up with a very inexpensive below-decks unit. In my case, as I have hydraulic steering and a center cockpit, the Cape Horn is the best bet because all I have to do is install a bypass in the hydraulic line.

The main reason for using the tiller pilot is because the windvane won't do much good under power. The servo is only 'powering' the turning arm for the quadrant so there should be no problem with confusing it. I hope.