Autopilots

Wheel, tiller and autopilots
puremajek
Posts: 751
Joined: Thu May 04, 2006 7:36 pm
Location: Brisbane Australia

Re: Autopilots

Post by puremajek » Wed Feb 15, 2012 8:11 pm

Paul

Couple of things. I am not the one to talk to about hydraulics's mentioned elsewhere in this forum (and with a vessel of my size and weight), I've been there - done that and the reason I now have a simple non-hydraulic system.
It got me thinking about redundancy and having back ups if we ever get as far as long ocean passaging.
I suspect this is your first challenge that you are going to have to address rather sooner than later and stick to your decision. Regarding our ocean passaging, in our case, this was discounted during the 'buying the plans' stage and to date we are very happy with that decision.

We have been very pleased with our system and the redundancy is twofold. If the electronic guts fail, you still have manual engagement of the Raymarine wheel pilot itself, engage the clutch and it will hold the wheel on a fixed course (with no electronic tracking and wind function corrections) - heading if you like (not strictly correct for the purists). So you still have basic course holding while you do other things. The only way this can malfunction is if you physically break the clutch or something else untoward happened in the wheel pilot section.

If the first two options failed, our last resort is to hand steer.
James
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44c
Posts: 1147
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Autopilots

Post by 44c » Thu Feb 16, 2012 4:37 pm

Jim wrote:If I never have to touch the helm on a trip on my boat I am a happy camper, I usually have the auto helm set before I go through the last channel markers. Only once have I had to turn the auto pilot off and that was in a big and short following sea when it just couldn't cope. Any cat I have ever been on, both power and sail are absolute pigs in a big following sea, they will not go in a straight line without huge amounts of input on the steering. They will turn up to 60 degrees on the top of a wave and shoot off on that direction, say to port, then when the starboard bow ploughs into the trough of the wave it rips around to starboard. For any autohelm to keep up with that sort of sea is a very big ask, and trying to keep wind in the sails is an even bigger ask. It is easier on those occasions to turn it off, save your batteries (and your mind) and steer by hand which will with quite a lot of effort make the boat track fairly straight. Perfect conditions for a parachute sail. But that is another subject.
Jim.

I guess the point is, a correctly sized autopilot will cope in those conditions. If you can manage by hand the A/P should be able to. For instance, the Simrad pilot I've ordered can handle (from memory) around 60 amps, so with the right sized pump it can really shift those rudders!

As for carrying a wheel pilot as a backup - nothing wrong with that idea, except if the main pilot should happen to fail in the kind of conditions described above.

My suggestion would be to set it up so you have a tiller as emergency steering, and then maybe a tiller pilot as a backup pilot. That way you have almost complete redundancy of the entire steering/autopilot system.

Jim
Posts: 691
Joined: Fri May 19, 2006 8:25 am
Location: Cairns

Re: Autopilots

Post by Jim » Fri Feb 17, 2012 12:07 pm

No autopilot, that I know of, that we could afford is Pro-active, they are all Re-active so when a boat goes off course the pilot will correct it and bring it back on course, how quickly it reacts can be adjusted in the response times settings within the system. Also the sharper the response the more of a drain it becomes on the batteries. In the situation described above the wind, gusting to 30 something knots and from behind at 160 to 170 deg. when the boat turned 10 or 20 deg to port (often) the Geona would wrap itself around the inner Forstay and try to flog itself to death. (no main up in a following wind on my boat) So in that situation without any sails up it would have been fine, the boat could wander all over the place and still end up being on course, however as we only had an hour or so to go I decided to hand steer as I knew what the boat was going to do well before the pilot and could keep it much straighter. I wasn't over the moon about hand steering but my Geona, wife and rigging were all much happier.
Jim.

44c
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Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Autopilots

Post by 44c » Fri Feb 17, 2012 3:38 pm

A suggestion, you might have already tried this, but anyway - have you tried using a tweaker downwind? ie an outboard sheeting point. I have a small block lashed to a midships cleat, with a third 'sheet' that runs through this. (I just swap it from one side to the other on different tacks) and running downwind, it holds the headsail to a much better shape. (I actually use it a lot, even on close reaches.)

You can see it in this video:



Sailing on the 'tweaker' I can actually get a fair bit (20' or so) 'by the lee' and the sail doesn't collapse around the forestay.

Jim
Posts: 691
Joined: Fri May 19, 2006 8:25 am
Location: Cairns

Re: Autopilots

Post by Jim » Fri Feb 17, 2012 7:00 pm

I do use that system, but I didn't know what it is called. I have one for both sides of the boat and for downwind I have them outside and attached to the base of the staunchens. Works well.
Jim.

44c
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Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Autopilots

Post by 44c » Wed Feb 22, 2012 9:03 pm

Early days yet, but so far the Simrad is @#%^&**&^ AWESOME!

I'll go into some of the features later....

44c
Posts: 1147
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Autopilots

Post by 44c » Thu Feb 23, 2012 8:25 am

Just SOME of the features:

Rates can be set to automatically switch from hi to low as boat speed increases.

Anti tack and anti gybe - when steering to wind angle the rudder rate will increase if the AWA gets too small (user adjustable) or too close to 180'.

Can be set to automatically switch to steer to TWA when running. Reduces chance of gybing when surfing.

Can steer to best VMG to windward.

Can pick optimum tacking times when sailing to windward toward a waypoint....

But best of all - it STEERS THE BOAT. :D

One point not mentioned on any website I've seen - if you need to connect to an NMEA 0183 source, you need to buy a NMEA/Simnet translator. Called the AT10 universal interface. Can get em in the states for about $100. Oh, and it needs a Simnet cable to connect it. $50 or so.

Smooth Cruiser
Posts: 583
Joined: Thu May 11, 2006 1:51 am
Location: Brisbane

Re: Autopilots

Post by Smooth Cruiser » Fri Feb 24, 2012 11:41 am

Sounds like it takes all the fun out of sailing! ;)

Actually - it sounds like a great unit!

Mick@itc
Posts: 69
Joined: Sat Jan 29, 2011 1:29 am
Location: Melbourne Aust

Re: Autopilots

Post by Mick@itc » Fri Feb 24, 2012 11:46 pm

44c wrote:Early days yet, but so far the Simrad is @#%^&**&^ AWESOME!

I'll go into some of the features later....
Hi
The SIMRAD you got was the AP24? Only the conponents in the kit in the link? Or more?
Thanks
Mick
Mick
If all you have is a hammer...everything is a nail!

44c
Posts: 1147
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: Autopilots

Post by 44c » Sat Feb 25, 2012 6:35 pm

I got the AP2402.

The 24 refers to the control head, the 02 refers to the course computer. The 02 comp can handle more current than the 01.

It comes with the rudder reference, and rate gyro compass, cables and a 7 way Simnet junction.

Basically everything you need except the drive. Hydraulic motors can be found on e-bay for around $300.

And as I said earlier, if you want to interface with NMEA 0186, you need the AT10 interface, and a Simnet cable. About $150.

So far, VERY impressed! :D

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