Catalina Factory Linear Drive Installation Issues

[Jeffrey Hare]

Hello,

I'm posting this for reference.  

Background:

The Raymarine linear drive Ram moves the bronze tiller arm that's clamped and bolted to the rudder post.  Edson makes that tiller arm that clamps to the rudder post.  In my conversations with Edson over the years, they are adamant that the ram connect between the slots in the tiller arm, not above or below.   Raymarine supplies a tiller arm bolt that is designed to attach the RAM outside the slot.  So there's that battle going on.

I've installed or consulted on quite a few Raymarine Linear drive installations since 2014.  I have always used the Raymarine bolt which attaches outside the slot, but never would I consider doing that without properly reinforcing the slot.  I noticed the Catalina Factory installation of the linear drive goes against Edson's recommendations and does not install a protective bushing.

Here's what I discovered when making some corrections to the factory installation to restore some of the excessively restricted turning radius.

The Slot was not reinforced causing the tiller arm to bend.

This resulted in both the slot deforming and bending the RAM bolt.

If the bolt were bent more than that I would have replaced it, however, I straightened the bolt gently using a vice, some shims, and a couple of nuts threaded to key positions.  I could tighten the vice gently and ease it back straight.  The nuts prevent thread damage and control where the bend occurs.

To unbend the tiller slot, I used a large bolt through the attachment hole with two nuts inside the slot.  Using a wrench to separate the nuts, I could ease the slot back into shape and the bushing would just barely fit.

 

In my installations, I've milled a bronze bushing from 1" Bronze prop shaft that fits tightly into the slot.  The bolt can now be torqued down without compromising either the bolt or the tiller arm slot.   

  

Summary:

I believe the approach I showed is (at least minimally) one correct way to install this autopilot ram connection to the tiller arm (assuming you're not going to attach the ram Inside the slot as Edson recommends).  To me, it's fairly obvious that you should never install it the way the Factory does this.  Perhaps it would never fail completely, but it shows a lack of understanding of the forces at work here.

Maybe I'll alert the Factory, but they haven't responded to any of my questions lately. 

It wouldn't hurt to inspect your own installations at some point.

-Jeff Hare

#17 Solstice