Auto Pilot and Auto Helm

Does anyone use either of these regularly.
I hear conflicting stories about the amount of power they use.
Can you only use while your engine is running?
What is your experience using them under sail?

Hi BB,
I'm with Gary, best piece of kit on the boat for short handed stuff, love 'em to bits..
It's important to play with the damping or sensitivity. If you have zero damping set, the helm is reacting every second, your wake looks like a drunken sailor and you're wasting power. Decrease the sensitivity so its only taking the sensor inputs every 5 - 10 sec and your helm calms down and your power draw drops way down.
Max damping is about one input every 30 secs and that's for flatter water. Zero damping is for when you're in big seas and getting tossed around. That's when you want the quicker response time so you don't get pushed into a broach or a gybe.

Balancing your sail plan is important and get some draft and curve in the sails. If you've got everything sheeted on hard and you're trying to point at 40 degrees the autohelm is working all the time trying to keep the boat nose pointing in the right direction. You can trim by listening to the autohelm, keep adjusting till you hear it go quiet.

With everything trimmed right, in 10-15 kn my helm might move an inch or so every 5-10 sec. With medium damping, a 400ah bank will last a couple of days without charging.
Cheers!
SB

A great response from all of you.
I recently planned a trip Bundeena to the CYCA which I usually allow four to five hours for, in light winds.
I was keen to try the tiller autohelm on my Swagman 28 and was travelling directly into the wind all the with just a little headsail up.
The winds were averaging ten to fifteen knots and the sea was medium to rough. ( I took a fall when a extra large wave hit the boat.)
I found I made very good progress and arrived at South Head significantly earlier than expected. The track on my chartpotter was surprising straight. I had run the autohelm for three hours constantly on all batteries.
I thought I should not push my luck with the batteries any further and sailed up the harbour. As it turned out no issues. I am guessing I should run it on the two house batteries and keep my starting battery separate.

I have just replaced my starting battery. I have had some electrical work done and my marine electrician Craig, (some of you may know him)) was amazed to see my two original house batteries were dated 2005.
I have minimal understanding of my electrical setup, but I have solar and wind power and bought the boat from a competent electrical engineer.

If no fridge, it will probably be the biggest power user on a small boat. Power draw will depend very much on sail trim, especially with the Raymarine ST1000/2000 (when these reach end of stroke the motor keeps trying to run and when this happens they draw several amps). So if you have lots of weather helm they will draw heaps of power (and eventually die). The Simrads don't suffer from this although they will still be working hard with bad sail trim. Over time, my ST2000+ draws an average of something like 0.25A. Quadruple that or more for heavy weather helm. Maybe double it for following seas.

As a guide, I have done several multi-week cruises with 60W of solar and an MPPT regulator (and no fridge) and never needed to run the engine for battery charging. This included one 56 hour passage where the tiller pilot worked non-stop, including through two nights and a fair bit of cloudy weather.

As stated by others, essential for solo sailors. Pretty important if only one crew too.

Cheers, Graeme

I find mine indispensable when soloing, so I agree with everyone on that. I was reminded of this a couple of weeks ago when I went out for a quick sail and it failed (chewed up cable in the steering pedestal), what a hassle! It's only one of the Raymarine wheel pilot models, but it seems up to the job for my 39 foot boat, but I'm on the edge of it's rating for that size/displacement. Yes I notice some current usage when just sailing, but as others have said, balancing the boat and getting the settings right on the pilot so it's not working overtime will help heaps. We have 260 amp hours in the house batteries, no solar or wind input (yet). With the typical weekend cruises we do, we just plan to motor now and then to top up the batteries anyway, so the wheel pilot usage isn't really an issue.

Also depends on whether you have a fully or semi-balanced rudder. Boat displacement specs are a very vague guide.

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Ramona said..
I use my windvane in 2 knots of wind!

Way to go. I have a transom hung rudder and at my next slipping I intend fitting a trim tab/wind vane self steerer but I need more info before building it.
So far look up says the trim tab area should be 20% of rudder area. Seems a tad to much to me.
Any links to trim tab self steering builds is much appreciated.

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Ramona said..

stray said..
The wheel pilots dont use much power only about 2.5 amps. If you use a windvane that suits the boat and is easy to set up, that will cover the stronger conditions.
I used this set up on a 36 footer and would switch to the vane as soon as there was enough wind. (12-15knots)
I hate the intrusive buzzing of the autopilot when sailing so prefer the windvane. If the wind is a bit unstable you have to adjust the vane pretty often but still better than hand steering ,the buzzing , and the power consumption.

I use my windvane in 2 knots of wind!

I would use my windvane as a paddle in 2 knots of wind.

The problem I find with windvanes in light to nothing 2 knot wind is the greater constant shift in apparent wind in those conditions. Because windvanes steer to apparent wind, a little puff of wind picks up boat speed and shifts the apparent wind changing the boats course.
You end up constantly steering the boat by correcting the wind vane,,, you might as well have the tiller in your hand or simply just turn on the tillerpilot