Autopilot

Anything that doesn't fit into the other Physical Systems categories
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Craig
Posts: 86
Joined: Sat Oct 10, 2009 11:44 pm

Autopilot

Post by Craig »

Has anyone used the CPT autopilot? It is an above deck unit. On their web site, they list a couple of Freedom 36's and a 38 as using them. Would consider for my 36/38.

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numbknots
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Location: Sunny Florida

Re: Autopilot

Post by numbknots »

Michel has posted some good info on auto pilots for Freedoms, most seem to work well only while motoring though. These Freedoms seem to eat them up pretty fast while under sail.
Numbknots
... currently experiencing performance anxiety..,

marno
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Joined: Sat Dec 06, 2008 6:21 pm

Re: Autopilot

Post by marno »

I have a Raymarine Wheel Pilot, which I replaced the wheel unit on recently. On my 39 it will only cope with motoring (but not in decent sized seas) and in mild conditions hard on the wind. I wouldn't bother spending my money on an above deck unit for all round use, I'd go to a below deck unit, which I probably will do when I get back to Oz, as there are times when I would prefer an autopilot to my windvane.
Cya
Marno
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GeoffSchultz
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Re: Autopilot

Post by GeoffSchultz »

I have a RayMarine Type II linear drive which has had absolutely no problems steering a 40/40 in just about any condition that you can imagine. I use a S3 Corepack with a gyro (don't go for the external gyro) and that really added stability/predictability. I've only had 1 failure of the linear drive when one of the brushes made intermittent contact, but other than that it's been great in 12 years/40K+ miles). Low power consumption too under most situations. I do carry a spare linear drive (and control heads and display heads and instruments and ...), but most go unused.

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

marno
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Re: Autopilot

Post by marno »

Gday Geoff,
Just a query, I was planning on getting a nice big hydraulic ram (for fast hard over times and to handle nasty weather) when I get around to my autopilot. Is there an advantage to the linear drive over the ram that you are aware of? It's always good to ask someone with real world experience.
Thanks
Marno
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GeoffSchultz
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Re: Autopilot

Post by GeoffSchultz »

marno wrote:Just a query, I was planning on getting a nice big hydraulic ram (for fast hard over times and to handle nasty weather) when I get around to my autopilot. Is there an advantage to the linear drive over the ram that you are aware of? It's always good to ask someone with real world experience.
I've never had a boat with a hydraulic ram, so I can't provide any real-life comparison. However, looking at the specs (http://www.raymarine.com/Default.aspx?s ... 2&page=219), the RayMarine Type II linear drive that I have is limited to boats of 16.5 tons or less. The Type II hydraulic drive is for boats up to 24 tons (http://www.raymarine.com/ProductDetail. ... RODUCT=355). Considering that the 40/40 is less than 12 tons, the linear drive is well suited. I would think that it would be fine for the F39 also, given its displacement of less than 10 tons.

I think that the linear drive has the following advantages:
  1. Single component. You don't have to install/plumb a hydraulic pump.
  2. Lower power consumption as you don't have to keep pump pressurized.
  3. Lower cost.
  4. Very quiet.
I'm sure that the hydraulic system has advantages over the linear drive, but I'll let someone with a hydraulic system address those.

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

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Michel
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Location: Zaanstad, the Netherlands, EU

Re: Autopilot

Post by Michel »

Marno,

I have an hydraulic ram on the F44. It's a huge cylinder, 2' long. Connected to Hynautics hydraulic components and a Robertson AP20 brain, Robertson RP160 pump, control head and rate gyro compass. There are several yards of hydraulic hose and lots of hose connections. The whole installation is professionally installed and designed, I have the design and dimensioning drawings. The set steers the boat well even under heavy conditions running under full sail with following seas at between 8 and 11 knots. The yawing is sometimes scary but the pilot gets the boat back in line well each time. But:

- power consumption is high, around 10 amps continuously under the above circumstances.
- my hydraulic fluid tank is pressurized and looses pressure over time. I then have to crawl into the lazarette with a bike pump to pressurize the tank. There must be a leak somewhere.
- there are many points where leaks could develop at the hose connection points.
- under less challenging then the above circumstances, the pumpmotor got hot on two thirds of my last trip to England and stopped working. We had to steer by hand for 40 miles. Turned out dust from the brushes got into the grooves of the collector. After scraping out the dust, it worked again, but I still feel uncomfortable with this issue. Could be I stay out of trouble for the next 10 years, but could also have trouble next month. A bigger pump motor that doesn't get so hot would be 24 volts and would require rewiring and probably even more battery drain.

All in all I would opt for the most simple system, provided it's strong enough, so that would not be the installation I have.

I advise you to have a look at the very powerful and compact Jefa rotary drive motors with fast planetary gearbox. They might be a very good alternative. Another brand you could look into is NKE, the French brand of autopilots used exclusively on open 60s and mini650s. I don't know if their components mix with other brands of autopilots; they're French after all. The Danish Jefa can be installed with any autopilot; Jefa only supplies the motor and gearbox and linkages.

Anyway, I'm glad I have a Hydrovane now as a backup when captain Robertson gets tired.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

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