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Old 06-05-2010, 05:41   #16
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What is a typical power drain for an autopilot?
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Old 06-05-2010, 06:33   #17
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Mark J makes an excellent point. One certainly gets to know their boat and develops that “special” relationship with her. Personally, I cannot imagine NOT spending, hours at the helm, particularly offshore.

We were forced to steer by hand after day 1 of the passage from the B.V.I.’s to Toronto. There were two people and one teenager who spelled off once in awhile. The Hudson, Erie, Lake Ontario was a bit Brutal without autopilot, but such as life.

That leg, there was the “ teenager” and an eight year old girl, spelling off. This was the kid’s first exposure to sailing, They didn’t know any different, so there were no complaints!!

Just, “ hey, mom, I am hungry......
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Old 06-05-2010, 06:38   #18
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Balance the sails

being "forced" to hand steer will help you learn to balance the boat with sail trim.
most boats will stay on course once the sails are trimmed and balanced correctly. it will also have the effect of getting best speed.
if you cannot get your boat to sail on course for hours at a time in steady wind the rig needs to be tuned.
i have an auto pilot but only use it when motoring. once the sails are up i can trim to course.
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Old 06-05-2010, 07:09   #19
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What is a typical power drain for an autopilot?
I don't know exactly.
Before we had solar panels we used to charge by running the engine 4 times per day for 20 minutes each time, and 6 times per day for 20 mins in rough weather.

Now with our 2x120watt solar pannels we can run all the time and still keep the batteries topped up

Mark
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Old 06-05-2010, 07:28   #20
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Of course you CAN do it by hand-steering, and you do have a backup because you've got to APs but what if you lose power, or your engine stops working so you can't generate it?

I did ocean passages on 9 different yachts to get from EU to NZ and the biggest ongoing technical problem that people had was power consumption. If you use a windvane you probably avoid most of these problems. In your situation I'd sell both APs and get a pendulum-style windvane and a tiller pilot with the money I made. The tiller pilot can steer the boat via the pendulum.

Having said that though, I'd be seriously tempted by a windvane that used an auxiliary rudder, as then when my rudder falls off, I've got something else to steer with.
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Old 06-05-2010, 07:34   #21
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Having said that though, I'd be seriously tempted by a windvane that used an auxiliary rudder, as then when my rudder falls off, I've got something else to steer with.
We have an auxiliary rudder windvane now. Had servo pendulum before. If I could choose, I'd go for the pendulum any day. More cons than pros with the aux. rudder.

You can make a tiller pilot steer using an auxiliary rudder with trimtab too though.

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Old 06-05-2010, 07:52   #22
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We have an auxiliary rudder windvane now. Had servo pendulum before. If I could choose, I'd go for the pendulum any day. More cons than pros with the aux. rudder.
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That's because you haven't had your rudder fall off 300 miles from land - it focuses the mind somewhat and changes your priorities!
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Old 06-05-2010, 08:31   #23
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The power drain is usually recorded in the owner's manual. I have an old Autohelm 800 and it's listed in there. It's like .25 amps in "standby" and up to 2 amps when active, and steering against a load.

Bear in mind that my boat is only 25' and 2.5 tons displacement and my autohelm is a small tillerpilot model. A larger boat, and a larger autohelm would probably use more energy.
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Old 06-05-2010, 08:44   #24
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What is a typical power drain for an autopilot?
Really good question and for sailboats a critical question but sort of like asking what is the typical gas consumption of a car. Depends a lot on which car, 2010 Toyota Prius or 1969 Corvette so 45 mpg or 6 mpg.

Power drain for the AP will depend on the boat and how well you trim and balance the sails to ease the work load of the AP. Then there is a variation in power use by different APs as well based on how smart they are (less hunting), size and efficiency of the motor, whether the unit uses electric clutch, power draw of the brain, etc.

General answer, several amps. Probably will be one of the larger power draws on your boat, right next to refrigeration.
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Old 06-05-2010, 09:12   #25
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General answer, several amps. Probably will be one of the larger power draws on your boat, right next to refrigeration.
That's the sort of answer I was looking for - not an exact ampage. I can see the reasoning behind windvanes given a power drain of that nature, but obviously it also depends how much time you spend sailing from place to place.

It's a bit like fridges. If you want to run your fridge at 0C it will take more power than running it at 4C (which is usually adequate in most homes). Duty cycles need factoring in as well.
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Old 06-05-2010, 09:17   #26
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sailing local waters and inshore:autopilot oceancrossing : windvane
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Old 06-05-2010, 09:43   #27
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sailing local waters and inshore:autopilot oceancrossing : windvane
Agree in the best of all worlds. For some it just isn't practical. In my case the transom height and angle is not ideal for wind vanes. Plus there are davits which will become mounting spot for solar panels plus the boarding ladder. Just doesn't leave a lot of room for a vane.

Now if someone could design a windvane that mounts on the bow.
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Old 06-05-2010, 10:28   #28
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Agree in the best of all worlds. For some it just isn't practical. In my case the transom height and angle is not ideal for wind vanes. Plus there are davits which will become mounting spot for solar panels plus the boarding ladder. Just doesn't leave a lot of room for a vane.

Now if someone could design a windvane that mounts on the bow.
The Autohelm wind vane allows the upper unit, the airvane, to be mounted remotely.

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Old 06-05-2010, 11:16   #29
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We've raced a couple miles without an ap but cruising is another animal. With two ap's I would not worry much, if they both go in the crapper you CAN drive.

I think sometimes we overthink this stuff.
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Old 06-05-2010, 11:20   #30
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I love the idea of using a cape horn windvane, but the $4K cost is just so brutal.

Outboard Models

We've got an autopilot right now that works, but I hate trusting it. MarkJ's comments make me think that using it, and keeping a spare or two onboard, might just be the best way to do things.
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