This is the way the 81 model at least was made at the factory. The original angle beam was rusted out, they used steel which lasted for 20 years so I re-made it and primed it with industrial primer. The all-thread shown at the left is something I added, youll see the final configuration in subsequent photos. Also, youll notice that the top bearing has been re-located under the shelf. This was done to strengthen the upper support and to provide a better thrust surface for the rudder to ride on. This also positions the rudder lower in the water so the rudder does not rub against the stern underbody, a big problem with many 37Cs

81 37C factory rudder configuration

This is the bushing I had machined at a local machine shop. Many 37Cs have a very weak rudder support at the the rudder shaft through log. There is nothing but fiberglass to act as a bearing and it wears out and gets sloppy, not what you want when adding a below deck auto pilot. Actually, not what you want period, first time I was off shore in some rough seas I opened the lazarrette and saw my rudder shaft moving quite a bit.

Bushing support

I had the bushing made in two halves so I could install it without dropping the rudder or hauling the boat. It then becomes a simple job of drilling a couple of holes to install.

Rudder Bushing split view

I was going to have it anodized but I got in a hurry so I just painted it.

Rudder bushing painted black

I adjusted the rudder shaft carefully after loosening all the steering cables so I was in the center of the shaft log and drilled the two mounting holes. I actually started with the bushing on top of the beam, used clamps to hold it in place and match drilled through the bushing holes as a drill guide. I then repositioned under the beam to get the bushing as low as posible for the most strength. This took all the play out of my rudder and relieves all the load at the hull. This makes the rudder extremely strong and I sleep better knowing Im not wearing away the bottom of my boat. If you look at true blue water boats, they all have bearings on the rudder shaft. This is a big weak spot in the 37C and my plans are to make passages in this boat. I wont worry about this liability any more. I was going to support the back of the bushing as well, but once I got it installed it was so stable I didnt feel a need to do so.

Installed on angle beam

Another view

Everything fits, I didnt have to make any modifications to the cover plate at all.

Completed Job! On to the autopilot installation!

This piece is a little over kill but it would have taken forever to machine to a smaller size, Its solid T6061 aluminum block split at the base to allow for installation without dropping the rudder. Edson makes one but they are pretty proud of it and aluminum is much cheaper than gold... that must be what its made of for the price.

Rudder control arm installation for autopilot

OK, I know this thing is too big but it will never break.

Arm and Bushing, another view

This supports the electro hydraulic actuator arm capable of excerting 1400 lbs of force to the actuator arm, now you know why the arm is so big. The platform is a 2X10 pressure treated lumber cut to size to fit over the cutout. Fortunately, Hunter overbuilt this area and the unit is very secure. Its fastened with 1/2 stainless carraige bolts

Platform for autopilot actuator

Actuator installed on its pedastal on the platform. The unit is a AutoNav autopilot system capable of steering up to a 65 vessel. It hooks into my Nexus server and electronics as a completely integrated system. The drive system is the same as the one used by B and G for about half the price. Nexus and AutoNav are now part of ComNav. Great stuff!

Actuator insallation

Connected to control arm

Another view of completed mechanical assembly

In this view you can see how the actuator attaches to the control arm. One of the great features of this system is you can quickly undo the clevis pins on the arm and the pedestal and remove the actuator and stow it away when you are just day sailing or racing and you dont want to drive the mechanism. You can also see the relocated upper support bearing on the underside of the shelf. You can see the all-thread in the background. This reinforces the upper shelf by carrying the upwards loads of the bearing to the better supported shelf below.

Control arm attach point, upper bearing support

Well thats it for the mechanical installation. Next comes the electrical hook-ups and sea trials. If anyone is interested in the hardware, Im in the owners directory and I can put you in contact with the machine shop that did the work. Its all on CAD so he can make minor changes to fit some other installations as well.

Another view the arm with the all-thread supports