Jetmart,
I have been looking deeply into this for the past week or so, and have spent several hours on the phone to numerous parties about this issue. My conclusion:
The inherent flaws of cable steer, i.e. play in the system, heavy steering, ect..., will leave the Octopus setup a distant second. The constraints of the design will never allow the Octopus to be smooth...especially in turns. It's off the table for me.
However, there are fully hydraulic solutions, and I have found one that is VERY compelling, albeit likely expensive. While most hydraulic steering systems have hydraulic lines connecting at the helm, the Optimus EPS system does not. It is steer by wire.
http://www.seastarsolutions.com/pro...-steering/optimus-eps-inboard-and-sterndrive/ The chain goes like this: Steering helm changes to a new electronic helm, with only a data wire to the hydraulic control head...which is located near the drives. Two separate hydraulic pumps are fed by the control head, which feed individual "smart" cylinders, which are connected independently to each drive. There is no need for rudder feedback units in the water, as the position data is integral to the smart cylinders. And if interested, autopilot can then be added with a simple connection between the autopilot electronics, and the steering system control head. All major manufacturers make an autopilot interface, intended for "steer by wire" systems.
The actual helm control offers a couple features that are not available in a simple all-hydraulic system. The ability to change steering ratio at slow speeds vs faster speeds...selectable by the operator. Tighter steering for slow speeds, makes running the vessel off-plane easier, docking easier, ect. Less aggressive ratios are set at higher speeds, to avoid jerky steering. All selectable by the operator via a helm user interface. Weight of the steering feel is also adjustable across all speeds.
What's really interesting is that this system can also be expanded to full joystick capabilities...with the addition/conversion to Digital Throttle Controls. That "enhanced" system is referred to as Optimus 360. Turning your boat into an Axius type system is completely possible if you want to go that far, and it can be done in stages. I won't be doing that, as I have a bow thruster, and that's enough for me. Just getting rid of the stiff steering and play in the steering wheel that is ever present in cable steer would be my goal. On a related note, I'm told that all Formula PCs are now coming out of the factory with steer by wire.
Back to autopilot: There's no need for a separate hydraulic power pack, as the hydraulics that power the steering cylinders are utilized instead. All you would need is a "steer by wire" autopilot package from one of the major manufacturers. If I were to go this far, about 2.5K more would get full autopilot capability, in a system that would be smooth and largely constraint free from an engineering perspective. Here's a link to Garmin's version of all you would need to add:
https://buy.garmin.com/en-US/US/p/599973
And Raymarine's version of the same. This includes a generic one size fits all schematic which shows the Optimus EPS interface:
https://www.raymarine.com/view/index-id=7686.html
Lastly, here's a pretty good video explaining the basics of the system. Although it's a single engine outboard application, there are also stern-drive packages for dual engine setups as well:
https://www.youtube.com/watch?v=2HYi3T_DwC0
Lots more I could share about how it all comes together, but that's enough for now. If you want more info, reach out....
Best...
V1