This piece of the puzzle is pretty easy to install, so this will be a short post. In fact, there's only one cable that extends from the rate compass, and it simply plugs into the Simrad network backbone. Routing the cable is the hardest part. My network extends through the radar arch, down to the starboard side next to the helm seat, and into the helm. I have a T-connector behind the helm, so that's where the rate compass cable has to plug in. However, the rate compass should be installed away from other electronic devices, and the helm compass, so I had to think for a while before I came up with my solution. On the starboard side of the boat, in the cabin, there is a hanging locker for the mid-cabin. Those of you with 1999 - 2002 340s know what I am talking about.
This locker is near the back side of the helm, so cable routing is short. Also, it is near the center of rotation for the boat, and that is the best location for a rate compass. I took a couple pics, while I was on my knees in the mid-cabin, looking up. It's a tight spot, and I had to take the pics from close range, so the perspective isn't great, but you'll get the idea.
The rate compass is about 6 inches above the hanging rod, but it's hard to tell from the pics. If you open the door to the locker, you can't see the device unless you bend down and look up, so it's well protected and safe from damage. I drilled one hole from the locker into the helm area, and sealed the penetration with a grommet and some 3M 5200 Urethane sealant. The display showed the device at power-up, so it's functioning properly. Next, the pump and computer will be getting installed and configured.