Autopilot for Rack and Pinion Steering - Page 2 - SailNet Community
LinkBack Thread Tools
post #11 of 12 Old 03-21-2007
Join Date: Nov 2001
Posts: 42
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
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.

cpcohen is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #12 of 12 Old 03-21-2007
Larus Marinus
Idiens's Avatar
Join Date: Jan 2007
Location: Brussels
Posts: 1,756
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 11
Originally Posted by witzgall
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.
What is it attached to? Can you access the other end of the wheel's shaft?
I think most wheel mounted autopilots are a bit weak for a 47 footer. So you may need an internal actuator anyway.
Idiens is offline  
Quote Quick Reply Share with Facebook

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Forum Replies Last Post
Steering System Spring Checkup Tom Wood Gear and Maintenance Articles 0 04-26-2004 09:00 PM
Steering System Spring Checkup Tom Wood Cruising Articles 0 04-26-2004 09:00 PM
Steering System Spring Checkup Tom Wood Her Sailnet Articles 0 04-26-2004 09:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome