One door opens, another closes: auto tiller!

[kpgraci]

I’ve got this prioritized list of boat projects, and since my boat is a floating project boat, it’s a long list. Roughly ordered by price vs need, an auto tiller was way down the list. Until Sunday, when browsing eBay I found a deal on a new Raymarine ST1000 Plus.

I single hand a lot, so I could argue this is a necessity in order to raise the sails, but at the same time I feel like I’m betraying the sailing gods. I’ll sit with both sheets in one hand and the tiller in the other, feeling every pull on the boat, the force of the wind in the jib; it’s quite a connection to the boat, wind and water.

I can always do that when I want, sure, but I won’t have to, and that’s the difference. When my son sails with me I enjoy relaxing and just going for the ride, so I have no doubt I’ll let my new friend do a good bit of the work for me.

Like most of the posts I’ve read on the subject I’m sure I’ll feel this is the single best improvement to the boat and my sailing enjoyment I could have make, but somehow I fear I’ll be losing a little bit of the simplicity of sailing.

But then, even though I enjoy walking I don’t mind driving my car. I’m sure I’ll get over it.

 

[Roger Long]

Be very careful not to let that unit go all the way to the limit of travel. It has no limit switches or clutch. The motor will simply stall and burns out in seconds. The assumption is that you will always be watching and tending it. If you should go below to use the head and a wind change makes it impossible for the boat to hold course, you may come up to a dead unit. I went through two before I figured this out. Otherwise, they are good autopilots.

It is possible to add limit switches if you are clever:

http://www.cruisingonstrider.us/ST1000mods.htm

 

[kpgraci]

I've heard that about this unit, and yes, while I think I'm clever my wife often disagrees. Thanks for the link.

 

[Stu Jackson]

I sailed for many years without one, and in fact added mainsheet to tiller self-steering on our C25 based on John Letcher's great little book, Self Steering for Small Craft. I finally "broke down" and got a Navico tiller pilot. Like ATMs and microwave ovens, how'd we ever live without 'em?

 

[kloudie1]

Ahhhh.. Monsieur Piloto , Otto Piloto, is my friend!
You will enjoy it, Ken

 

[kpgraci]

It is possible to add limit switches if you are clever:

I did not realize at the time this was your work, very nice. I doubt I'll crack open my new auto pilot, but its good to know it can be done. I guess raymarinne was not interested in your mods, too bad.

 

[Joe]

I have an autohelm 1000... came with the boat when I acquired it 12 years ago. It's still running fine. It's the precursor to the Ray 1000. I have never had the issue that Roger describes. It simply stops and the warning signal comes on when it reaches its travel limit.

Two very important tips.....

1) make sure you have your rig ballanced to get the best performance from the AP.

2)When single handing and using the AP... ALWAYS wear your harness and tether and stay clipped on to the boat.

 

[Roger Long]

I have an autohelm 1000... I have never had the issue that Roger describes.

That's because it is a different unit. The ST1000 Tillerpilot has no travel limit warning buzzer. There is a function that causes it to shut off and start beeping if it can't hold the course. This will protect it in many circumstances and may be the reason why the engineers thought they didn't need limit switches.

The problem arises when the boat slowly goes out of steering balance and the autopilot reaches its full travel but boat continues close enough to the requested course that the off course circuit doesn't trip. The steering characteristics of some, or many, boats may prevent this from happening but my boat did it quite consistently. The motor got so hot the second time that it melted the solder on the circuit board and electronic pieces were rattling around in the case which was slightly melted.

 

[Roger Long]

I doubt I'll crack open my new auto pilot, but its good to know it can be done.

If you are primarily using in while you are sitting in the cockpit and watching it, you probably won't have a problem. With a tiller steered boat, full Tillerpilot extension will translate into a large rudder angle.

My installation, where the tillerpilot was hidden and not steering the boat directly, was an extreme case. Still, you should be aware of it.

 

[Stu Jackson]

And just to repeat what might be obvious to some: follow the bloody instructions about where to locate the unit vis-a-vis the distances fore and aft on the tiller and distances from the tiller. They didn't just make that up to make it hard to locate on your boat because of opening hatches and coamings. Don't over extend the autopilot arm like many have tried to do.

Many folks who had my old boat did all sorts of "work arounds" to avoid drilling the hole in the cockpit seat to locate the main pin for the AP. They "invented" all sorts of cantilever arrangements, none of which worked properly. I drilled a hole in the seat, backed it up with a heavy epoxied-in piece of painted plywood beneath, bought an under-tiller mounting arm for the pin, and it worked just fine. Others had them mounted off the coaming, too far away and beyond the recommended dimensions. Their reasoning? It would mess up their cockpit cushions. My then 12 year old daughter solved that one: just push the cushion forward and it bent up against the back of the cabintop and made a great backrest! Brilliant kid...have NO idea where she got her smarts.

 

[Don12364]

My experience over a number of years with the 1000 was that it would reach the end of its travel, the motor current would build instantly to the 'stalled' level and the pilot's internal protective circuitry would cut the current dead - thereby saving the motor from burn out.
It would then wait for a few seconds and try again. If the compass was still demanding further ram movement in the same direction the system would go through the same sequence and cut out again with the ram at its limit.

I found this could go on endlessly and without time limitation and I regularly allowed it to do this when I was taking down my sails when single handed. I simply used to set the engine throttle to dead slow, set the pilot on head to wind and go forward. Some times the wind or waves were too strong to allow the pilot to hold the boat head to wind and the pilot would eventually go to its limit. Unless the boat actually turned so that it became problematical to carry on furling I just allowed the pilot to remain switching on and cutting out. If I had difficulties I sometimes took 10 minutes to furl and stow both main and genoa.
Though of concern, it did seem the design of the ball screw was adequate to allow this.

Calculations:- (With apologies to all non-techies)
Assuming the normal running current on full load was 3A and the stalled motor current was 9A. i.e. 3 times the maximum running current (Crouzet motor 82800801).
And the pilot's over-current cutout was set at, say 8 A then the instantaneous power dissipation in the armature would be more than double the normal running power.
And if the overload circuit took 1/2 second to detect and cut off this current with a 5 seconds pause before the next attempt; then the average power dissipation would only be a quarter of normal running power. [0.5÷5 x 8÷3 = 0.27] and motor burnout would be impossible.

However one way of burning out the motor would be to supply it with insufficient current to prevent it from reaching the over-current condition necessary to switch off on its limit stops but still enough to enough for it to reach normal operating torque. i.e. Too thin or too long supply wiring.

In a light duty application one would think the motor would never need much current and so the wiring could be light and long. Not so because the motor would still need to draw the 8 amps for the over-current protection to work. If not the current would rise to almost 8 amps and stay there. With a 1.33 ohm armature resistance plus another 0.167 ohms in the wiring, the power dissipated in the armature would be a steady 85 watts and burn out inevitable after a minute or so. For this the cabling required would be 20' of 16 AWG doubled.

However, as Roger appears to have twice burned out the motor when the system should have prevented this event regardless of how it was being used then either he or I had a non-typical unit. Clearly the current overload setting either differed or was never achieved.

 

[Joe]

That's because it is a different unit. The ST1000 Tillerpilot has no travel limit warning buzzer. There is a function that causes it to shut off and start beeping if it can't hold the course. This will protect it in many circumstances and may be the reason why the engineers thought they didn't need limit switches.

The problem arises when the boat slowly goes out of steering balance and the autopilot reaches its full travel but boat continues close enough to the requested course that the off course circuit doesn't trip. The steering characteristics of some, or many, boats may prevent this from happening but my boat did it quite consistently. The motor got so hot the second time that it melted the solder on the circuit board and electronic pieces were rattling around in the case which was slightly melted.

Were you using the device on your 32 footer? I'm wondering if the larger unit....Raymarine ST2000 Plus Tillerpilot... might prevent some of the problems you described. Otherwise....nevermind.

 

[Roger Long]

However, as Roger appears to have twice burned out the motor when the system should have prevented this event regardless of how it was being used then either he or I had a non-typical unit.

I took my second burned out unit down to the Raymarine's regional headquarters and the tech opened it up while I was there. I didn't know at that point why the first one had failed after two weeks.

The tech told me that there was no kind of full travel cut off. Since it was a tiller pilot, the designers didn't think it would ever be allowed to go to full extension long enough to cause a problem. If it went to full extension, the boat would keep turning and the "unable to hold course" function would kick in, shut off the motor, and start the alarm beeping.

I've observed all three units I've owned grinding against their stops with the motor stalled and none went into any over current shut off mode. Perhaps, if they are already exerting significant force and come up against the stops, they will trip off. Free running however, they will not.

What is odd and out of the design parameters for my set up is that there is no real load on the tiller pilot. It simply positions the lever on the wind vane linkage that makes it think the wind vane moved and the servo oar on the Cap Horn wind vane provides the steering force. If a helm load plus full travel stall is required for over current protection to trip, that would explain this.

 

[kpgraci]

My experience over a number of years with the 1000 was that it would reach the end of its travel, the motor current would build instantly to the 'stalled' level and the pilot's internal protective circuitry would cut the current dead - thereby saving the motor from burn out.

I really don't like the sound of that, even though you say the unit experienced no damage. I suppose having the over-amp/over-heat safety kick in is better than not.

The ram has about a 6 inch travel either way, if my trig is correct, mounted 18" above the pivot means a 19* tiller travel port or starborad, If I move the tiller 19* the boat is going to turn in pretty much any conditions I expect to be sailing in (unless I'm not moving...)

 

[Roger Long]

(unless I'm not moving...)

That's when you'll have trouble if you aren't paying attention to the unit. The wind goes lighter and lighter requiring more and more helm. The unit goes to full extension but the boat is still pointed in the right direction because the wind has died. If the boat doesn't drift off course enough, the motor will make like the Japanese nukes.

I don't thing you'll actually have a problem with it though. It makes some alarming noises hard over. This is more of an issue for people who are using them with windvanes when the boat is under power. A little miss-adjustment of the wind vane steering lines and the boat can keep going in a straight line with the unit hard over. The engine noise masks the sound of the tiller pilot dying.

 

[kpgraci]

Thanks all. Hey, it's a 22 foot boat, I won't be on fore deck drinking Mai Tais, I'll be sitting right there with it the cockpit. (drinking Mai Tais)

 

[Joe]

Thanks all. Hey, it's a 22 foot boat, I won't be on fore deck drinking Mai Tais, I'll be sitting right there with it the cockpit. (drinking Mai Tais)

Don't worry about it....... it hasn't broken yet, and it probably won't... anyway, what are the alternatives. Just enjoy it... you'll be glad you have it.

 

[kpgraci]

ha

I planned on letting this thread go, but I fould this pic and I counld not resist. Here's how I intend to use my new tiller pilot.

 

[Joe]

I planned on letting this thread go, but I fould this pic and I counld not resist. Here's how I intend to use my new tiller pilot.

That's perfect..... just don't roll out of the hammock, over the side, when the PWC idiots buzz you.