|Topic Review (Newest First)|
|03-21-2007 05:53 AM|
Originally Posted by witzgall
I think most wheel mounted autopilots are a bit weak for a 47 footer. So you may need an internal actuator anyway.
|03-21-2007 03:17 AM|
There's a problem with using a "ram-based" autopilot connected to the steering quadrant.
You'll be turning the steering wheel along with the quadrant. It will be geared-up by the rack ratio. This is not an efficient use of autopilot driving power.
It may work fine, or it may not. A moving steering wheel might be unfriendly to people in the cockpit. A _locked_ steering wheel could cause all kinds of trouble for the ram.
I can see several ways around the problem:
1. Use a pilot that drives the wheel, and mount it in the cockpit. I know you don't like that idea, but it may be the simplest thing to do. It's possible to build a pivoting mount for the drive motor (or a tensioner for the drive belt) that would let you disconnect the drive belt when not using the autopilot.
2. Put a cogged-belt pulley on the steering wheel shaft, underneath the covers ( between steering wheel and rack). Mount the autopilot motor under the covers, and run a belt between the motor and the steering shaft. You'll need some way to freewheel the belt (or a motor that turned freely when not powered). The motor and belt would be protected from weather, and invisible. The mounting details for the pulley would have to be worked out.
In either case, you'll have to think about lock-to-lock time, which should be about 15 seconds for good autopilot performance.
If you could lift the pinion off the rack and free the quadrant from the wheel, _that_ would let you use a ram on the quadrant. But unless the builders allowed for that possibility, it won't be easy to do.
I may be an old lady about this; driving the quadrant directly, and turning the wheel through the pinion, might work fine.
How heavy is the boat, and with what kind of rudder? That's crucial info for sizing the drive motor.
FWIW, I love my CommNav (ComNav?) 1420. I'm using a hydraulic pump, not a motor, but the control unit should be happy either way.
|03-20-2007 11:05 PM|
sailingdog: Me thinks you posted this in the wrong thread maybe..???
See I told ya, it's happening now.
|03-20-2007 11:02 PM|
Originally Posted by ianhlnd
|03-20-2007 11:01 PM|
|ianhlnd||Oh, yeah, then your're going to need a below decks pilot get ready for the $$$ Look at Alpha, although I think that may be for hydraulic steering.|
|03-20-2007 10:59 PM|
|ianhlnd||It's the aluminum which somebody says it's not from foil, the body produces aluminum by itself and it goes to your brain. Study funded by Alcan and Reynolds|
|03-20-2007 10:58 PM|
The boat is 47" (custom), but the wheel is not attached to a pedistal, so a wheel pilot would not work - at least not without running it to the cockpit side, which I would not want to do.
The rackand pinion is locaed directly behind the wheel, in a seat enclosure. There is not alot of room in there, but perhaps it could be modified to house a ram.
I guess I was just hoping there was a simple answer that I was missing...
Originally Posted by sailingdog
|03-20-2007 10:53 PM|
|03-20-2007 10:35 PM|
|sailingdog||Ian- you're dating yourself.. autohelm is now Raymarine IIRC. Some of the lower-end units will only tack through a fixed number of degrees, usually 100˚ or so.|
|03-20-2007 10:33 PM|
There's all kinds of AP's for both wheel and tiller steering. If you're under 32, suggest something that attaches above deck, as below deck is more expensive, and if you have to get at it, it's more difficult, like on a Catalina 30 and several others, you have to take off panels etc to work on it. Above deck, you got a motor and a belt, simple. Autohelm and Navicon or Navicom make very dependable systems, and look at the remote with the digital read-out. Great if single handing, punch in the degrees of tack, enter and there it goes.
The only thing wrong with the Navi-whatever, is that it's made in England. If you're not from England, you won't know what the hell they're talking about in the instruction manual.
|This thread has more than 10 replies. Click here to review the whole thread.|