Autopilot from scratch

[Rob Toronto]

Hey all,
I'm in year 6 of a 3 year refit of a steel 43' Mauritius Ketch.

Goshawk was home built in 1990, and we got her for a song knowing full well that we were more paying for a hull, and sound motor, rigging and sails than we were a 'complete' boat.
We've stripped, and rebuilt the interior, installed all new electrical, plumbing (engine and house), added very basic electronics (nmea0183) depth, speed, and masthead wind sensors, and a whole list of upgrades, and reworks.
I've been playing a bit with the OpenPlotter project as well. I've got it working to a basic experimental level, but have decided to just bite the bullet and eventually get a B&G plotter, radar, and nmea 2000 instrument package, and use my Raspberry PI, and OpenPlotter for secondary instrumentation (ie engine, tank, and auxilliary power monitoring).

Now more to the point;
Steerage is wheel to chain, to worm drive, to tiller arm. 2 1/2 turns of the wheel from lock to lock. I've got to (in the next year or so) install autopilot.
After doing some basic research, it looks like my 2 options are to add an autopilot that can drive the chain drive in a 34,000 lbs boat, or change to hydraulic steering, and go with a linear actuator style autopilot.
From the very basic research I've done it looks like the cost of changing to hydraulic steering and linear actuator style system is around the same, possibly even a bit less than getting an autopilot with a drive motor large enough to run the chain.

Stuff to consider;
Hydraulic steering as a practical upgrade? Is it a good enough reason to change from chain to hydraulic just on its own merit?
In my own mind, I see hydraulic may be the way to go when just considering power requirements. Am I right?
Need to explore: Durability? Cost? Complexity?

Any input is appreciated.
... One more thing to consider... This is our forever boat. We are currently living aboard, and are about 6 years from retirement. Once we're done work, we're heading south to the Caribbean, and MAYBE someday beyond, so long term value and reliability is a big consideration.

[gmakhs]

After sailing for the last few years , I can only tell you the only thinks electric autopilots do well is failing when you need them or randomly and consuming a lot of power .

Your idea of hydraulic is good and I believe the best option if you decide to use electric auto pilot .
Now from the other hand , you can manufacture a steel or fiberglass auxiliary transorm hugging rudder with a trim tab that can work with windvane or small tiller pilot , that way you will have 2 rudders in case of emergency and improved manaurabilty.

The other option is a servo pedalum wind vane .

In general wind vanes are more reliable and easier to repair than electric auto pilot .

3 auto pilots have failed me in the last 2 years , all of them the where over sized for my boat .

Ps : I don't know if it's only me but windvane creates a smoother motion on bad weather as well .

[billknny]

That's one opinion, but there a lot of boats bigger than a Beneteau 26 out there cruising full time with electric autopilots.

I do like windvanes, but Windvanes also can fail. (ask me how I know...)

Changing to hydraulic just to install an autopilot is not a good idea, and your existing system is reliable and robust. So why change it?

My suggestion: Install a Raymarine Type 2 linear drive. They are powerful, reliable, and VERY quiet. The direct connection to the quadrant gives you redundancy in case of failure of the mechanical system, something lacking in a hydraulic steering system.

If you want a back up to the linear drive, Raymarine also makes a chain drive unit that works well. Install both and have a back up ready to go with the flip of a switch. The alternative for a back up is to have a spare linear drive. Swapping them out is a very quick and easy procedure.

The key with any autopilot is to be sure that the boat is properly balanced and sails easily. If it is hard to steer by hand, fix the trim BEFORE turning on the AP. Reduced wear, and lower power consumption will be your happy result.

Originally Posted by gmakhs

3 auto pilots have failed me in the last 2 years , all of them the where over sized for my boat .

You are either buying crap, or installing them wrong, or abusing them. That's just not normal attrition for autopilots. My boat has been around the world TWICE with electric autopilots.

Originally Posted by gmakhs

Ps : I don't know if it's only me but windvane creates a smoother motion on bad weather as well .

If the electric AP gives a much poorer motion in a seaway that would mean it is not tuned correctly and is being asked to work much too hard. See previous paragraph.

[Jim Cate]

I've only steered a couple of boats with hydraulic steering, but in those cases there was zero feel to the helm... no feedback to tell you what was going on with the boat and her balance. I found this quite unpleasant and unsatisfactory. They also tend to be very low geared... that is, many turns lock to lock. Also unsatisfactory.

From reading others experiences, they are prone to leaking oil out and air in. The former makes a mess, the latter interferes with steering precision or worse.

I feel strongly enough about this that I'd personally not buy a boat with typical hydraulic steering. So, if your current cable steering gear is robust and well designed, I'd sure keep it and find an autopilot drive suited to it.

Besides the suggestions offered to now, you might have a look at Jaffa drives. They utilize a gear train driving a Pittman arm and drag link to the tiller arm (much like automotive steering systems). We've used a Whitlock drive which is similar in function for some 15 years with good success on our boat. The Jaffas are a somewhat more modern development of the same principle.

Finally, I too would consider a wind vane in addition to the A/P if voyaging is in the future for you. Their long term reliability and ease of third world repair is a big factor for long term cruising in out of the way places. The home built one we had on our previous boat steered her for around 60 K miles of the 86 K she carried us, and I miss having it now.

Jim

[thomm225]

Originally Posted by gmakhs

After sailing for the last few years , I can only tell you the only thinks electric autopilots do well is failing when you need them or randomly and consuming a lot of power .

Your idea of hydraulic is good and I believe the best option if you decide to use electric auto pilot .
Now from the other hand , you can manufacture a steel or fiberglass auxiliary transorm hugging rudder with a trim tab that can work with windvane or small tiller pilot , that way you will have 2 rudders in case of emergency and improved manaurabilty.

The other option is a servo pedalum wind vane .

In general wind vanes are more reliable and easier to repair than electric auto pilot .

3 auto pilots have failed me in the last 2 years , all of them the where over sized for my boat .

Ps : I don't know if it's only me but windvane creates a smoother motion on bad weather as well .

I'd like to get wind vane steering one day, but so far, my electric autopilots are doing fine.

I've had to make small repairs to both my Simrad TP10 (stuck buttons) and to my Raymarine ST2000 (had to screw the shaft back in) but otherwise they are working fine.

And my autopilos setup is not perfect. (the PO's setup) The pin on the tiller (and the cup) is in a bit to close and puts quite a load on the pilot but so far no problems. This over 7 years

[gmakhs]

1 st2000 have failed , and 2 drivers of EV100 the setup is correct , the main issue is that the drive even through is labeled for boat up 6 tones can't handle the beating when a wave splash on the rudder and eventually fails , raymarine authorised technician have check my setup and found everything fine and both drives where replaced in waranthy .
A friend of mine with a similar boat on 28 feet , had a.drive failure during the Atlantic crossing as well.
For now my third drive is working through a trim tab and is able to handle well .

If I knew I would have to manufacture a trim tab I would have spend the 1400euro for a windvane from.the beginning.
Once I reach Caribbean I will add a vane to.my trim tab and probably use the ev100 less or not at all .

[thomm225]

Originally Posted by gmakhs

1 st2000 have failed , and 2 drivers of EV100 the setup is correct , the main issue is that the drive even through is labeled for boat up 6 tones can't handle the beating when a wave splash on the rudder and eventually fails , raymarine authorised technician have check my setup and found everything fine and both drives where replaced in waranthy .
A friend of mine with a similar boat on 28 feet , had a.drive failure during the Atlantic crossing as well.
For now my third drive is working through a trim tab and is able to handle well .

If I knew I would have to manufacture a trim tab I would have spend the 1400euro for a windvane from.the beginning.
Once I reach Caribbean I will add a vane to.my trim tab and probably use the ev100 less or not at all .

My autopilots have gotten wet but haven't failed. Maybe I've been lucky. My autopilots do have a lot of pressure on them though due to the installation but have held up.

Quick shot at 23 seconds in.

https://www.youtube.com/watch?v=Q3I2zc0_7wY

[gmakhs]

The problem is not from water intrusion , the internal mechanism actually breaks , in the st2000 the arc that keeps the shaft , on the ev100 the gear next to the motor .

[lockie]

Originally Posted by gmakhs

The problem is not from water intrusion , the internal mechanism actually breaks , in the st2000 the arc that keeps the shaft , on the ev100 the gear next to the motor .

That's right: Raymarine ST1000/2000 tiller pilots have no end-of-stroke protection and will grind themselves to eventual death when the tiller ends up hard-over. The Simrads have built-in stall detection and hence are protected from this.

So you must pay strict attention to sail balance. Of course if you are in heavy conditions, the helm will end up hard-over repeatedly no matter what.

This is why after repeated failures and warranty fixes, I fitted limit switches to my ST2000, which now works beautifully and I believe its life-span will far exceed a new one.
Apologies to OP, now back to your topic....

Cheers, Graeme

[gmakhs]

Can you send me more info about your limit switches in pm or here ?

[thomm225]

Originally Posted by lockie

That's right: Raymarine ST1000/2000 tiller pilots have no end-of-stroke protection and will grind themselves to eventual death when the tiller ends up hard-over. The Simrads have built-in stall detection and hence are protected from this.

So you must pay strict attention to sail balance. Of course if you are in heavy conditions, the helm will end up hard-over repeatedly no matter what.

This is why after repeated failures and warranty fixes, I fitted limit switches to my ST2000, which now works beautifully and I believe its life-span will far exceed a new one.
Apologies to OP, now back to your topic....

Cheers, Graeme

Not necessarily. They will grind a bit then stop.

The fact is some of you guys just can't help but try to improve on things which usually make them less efficient

[SailRedemption]

OP all you need is a hydraulic ram and pump with a tiller on your rudder stock. You don't need to change your current chain steering. We have chain to wire quadrant but are about to install a Lecomble and Schmidt Type 50 autopilot ram. It will be controlled by a Pelagic autopilot computer. All in its about $4k, which is a good price. All we need is a tiller arm coming off our rudder shaft.

Jefa units are nice, but are more expensive than the L&S unit. Call PYI and talk to Phil about autopilots and he can answer any questions you may have.

Our boats are similar in size, we're 47' and probably 33k pounds sked hung rudder. That L&S unit will most likely be right for you too.

[Bruce K]

Originally Posted by Rob Toronto

Hey all,
I'm in year 6 of a 3 year refit of a steel 43' Mauritius Ketch.

Goshawk was home built in 1990, and we got her for a song knowing full well that we were more paying for a hull, and sound motor, rigging and sails than we were a 'complete' boat.
We've stripped, and rebuilt the interior, installed all new electrical, plumbing (engine and house), added very basic electronics (nmea0183) depth, speed, and masthead wind sensors, and a whole list of upgrades, and reworks.
I've been playing a bit with the OpenPlotter project as well. I've got it working to a basic experimental level, but have decided to just bite the bullet and eventually get a B&G plotter, radar, and nmea 2000 instrument package, and use my Raspberry PI, and OpenPlotter for secondary instrumentation (ie engine, tank, and auxilliary power monitoring
Now more to the point;
Steerage is wheel to chain, to worm drive, to tiller arm. 2 1/2 turns of the wheel from lock to lock. I've got to (in the next year or so) install autopilot.
After doing some basic research, it looks like my 2 options are to add an autopilot that can drive the chain drive in a 34,000 lbs boat, or change to hydraulic steering, and go with a linear actuator style autopilot.
From the very basic research I've done it looks like the cost of changing to hydraulic steering and linear actuator style system is around the same, possibly even a bit less than getting an autopilot with a drive motor large enough to run the chain.

Stuff to consider;
Hydraulic steering as a practical upgrade? Is it a good enough reason to change from chain to hydraulic just on its own merit?
In my own mind, I see hydraulic may be the way to go when just considering power requirements. Am I right?
Need to explore: Durability? Cost? Complexity?

Any input is appreciated.
... One more thing to consider... This is our forever boat. We are currently living aboard, and are about 6 years from retirement. Once we're done work, we're heading south to the Caribbean, and MAYBE someday beyond, so long term value and reliability is a big consideration.

Worm drive means you will never drive the wheel from the quadrant or tiller arm, so i think either convert to hydraulic; or drive from the chain or wheel.

[lockie]

Originally Posted by thomm225

Not necessarily. They will grind a bit then stop.

The fact is some of you guys just can't help but try to improve on things which usually make them less efficient

Well blow me down, I must have dreamt the time the belt stripped and I had to helm solo for 9 hours, and the time the motor burnt out, and the three times the drive rod unscrewed and fell out due to stall torque, right? You were there on my boat and I wasn't, and I just made this stuff up right? And I made it all up so I could spend hours designing and fitting the limit switches?

You can disagree with my opinions, but don't imply I am a liar when I simply report my own factual experiences.

Do a bit of googling on ST1000/2000 problems and you will see such failures are far from uncommon.

[boden36]

Bruce K is correct, your system as it is probably will not be able to be driven from the quadrant. You can test this by pushing on the rudder and seeing if the wheel spins easily in response.

We have had hydraulic for near 30 years and it has been as bullet proof as anything could be, and the ram sits on the outside of the transom in the weather.
Our old autopilot Coursemaster 230? drove the wheel by a large motor and chain. Worked well but was always trying to compensate for the boat's changing magnetic field as she rolled. This was annoying but irrelevant to our discussion.
I don't see why you can't cause an autopilot to drive a helm motor rather than a hydraulic pump.


Regards,
Richard.