Joe, great summary of the issues, thanks. This is consistent with much of the information I've received so far.
- The RS drive is electric, and requires 7A - less than most hydraulic drives. Apparently it also offers less resistance when not in use. The ACU 100 can supply just enough current (IIRC....) - The RS also has an electrically operated clutch (equivalent to the solenoid you mention) and requires this capability in the autopilot control unit. The Ray ACU 100 has no provision for this, the ACU-200 does. As you mention, the possibility exists to control the clutch manually with a switch, and in any case the RS can be overridden by hauling on the wheel in an emergency,. The ACU-200 was the smallest Ray ACU recommended by octopus, I believe this is due to the provision for the clutch.. - The RS has an optional rudder position sensor that is gear-driven and mounts as a module on the drive motor assembly - so no separate installation hassle. All Ray ACUs support this sensor. - The RS drive's motor is mounted remotely at the end of the supplied 6' bowden cable, on a 6"X6" plate, not sure of the height. Longer cables are available. It might be worth trying this setup with the ACU100 and saving a grand at the risk of blowing the output fuse. When asked about manually switching the clutch, the tech at octopus gave me something like a non-answer. Am going to mock up a drive/cable to ensure that I can make a really clean install. Will also explore local machine shops who might be able to fabricate a tiller arm. (if anyone else is interested, please reach out, and if anyone knows of a shop who can make one, would appreciate hearing more..) the edson unit seems very spendy for what it is. Dave 33-2 windstar. - Forwarded message ---------- From: "Della Barba, Joe" <joe.della.ba...@ssa.gov> To: "cnc-list@cnc-list.com" <cnc-list@cnc-list.com> Cc: Bcc: Date: Tue, 15 Oct 2019 12:31:01 +0000 Subject: Re: Stus-List Raymarine to octopus drive upgrade - UPDATE I have the ancient predecessor to that autopilot, the old AH-4000. I collect parts of them when I find them to have spares and recently was messing around with my drive units. One of them was always undoing itself, so I had a bungee for the lever to keep it on. The other one was doing the opposite, it would slip when loaded up. Full power on the engine was enough to make it slip. Apparently slipping is a belt too loose and popping off on its own is a belt too tight. I managed to combine the best parts of the slipping one with a couple other drives and a new belt and now I have one that neither slips nor pops loose :) I think the newer grey ones have a much easier way to adjust the belt. If your drive pops the lever loose on its own, try loosening the belt a bit. The EV-100 should be vastly superior to my old AH-4000 course computers. Mine will drive a ruler straight line upwind or in calm conditions, but following seas can confuse it and it really can't cope with a spinnaker in a lot of wind. Now for what you are trying to do, there are a few layers to the problem. One is the total current the drive transistors can control. There is no way the old 4000 could ever power a hydraulic drive. Maybe the EV-100 can sink that much current?? The next issue is the solenoid valve. Hydraulic units lock the rudder in place when the autopilot is on by closing a bypass valve and opening the valve allows you to steer by hand again. You would need to rig something to operate that valve. You could just have a switch on it you activate yourself, but this has an obvious pitfall if anyone but you is running the boat. The last issue is the algorithm the autopilot uses to steer the boat. You really would want a rudder reference and even then I can't say for sure how well the autopilot would adapt to a much different level of response than it expects from a wimpy wheel drive. You need the autopilot to NOT try ramming the rudder into the stops with full force. The wheel pilot can do that and not break anything, hydraulics not so much. Joe Della Barba Coquina C&C 35 MK I www.dellabarba.com
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