Ryan,

HYDRAULICS

  I'd like to disagree with you, largely because I don't want reality to mess up the nice simple theory of outboards and tiller actuators, but I can't make a strong argument against going with hydraulics.

  As far as hydraulic failures go, I've only seen three, only one of those has been on a boat, and the others were on heavily-abused heavy machinery.  So there's a lot to be said for going that route, particularly if you spend a bit extra to overbuild.  That said, if I never have to get soaked in fluid again, that would be fine with me.

  How would you set up the system on an HP with folding beams and tillers on exterior bidirectional rudders?  All the hydraulics could be in the lw hull, with just an enclosed cable going across the folding beams, but I'm not sure how I'd connect the actuator to the rudder.

  Or, I suppose you could have something underneath the circular mount s for the windward tillers shown on the renderings of the new ex40.  Then nothing would have to go across the beams other than whatever links the tillers to the rudders.

  Then again, if a tiller pilot could be mounted underneath the windward tillers, out of the weather, maybe I'd still give that a try and switch to a hydraulic actuator only if necessary.


SENSORS

  Two sets of directional sensors might make the most sense.  I was getting excited about the dual autopilots until I realized that would also mean dual sets of wind and speed instruments.  That would add a few more thousand dollars. 

  Maybe a single autopilot, with a single wireless solar masthead wind sensor and solar mast rotation sensor, and then two of the following:

    - Autopilot directional sensor
    - TackTick speed sensor
    - TackTick fluxgate compass

  If you were to switch the three sensors back and forth, the system might be able to figure out the rest. 

  The mast rotation sensor does a great job of taking mast rotation out of the equation, but it only works if it can compare itself to the compass, which is thankfully wired into an interior base unit.  If the compass were wireless it wouldn't work.  Likewise with the speed sensor -- it's wired into the base unit as well, and the system will pretty accurately compare wind speed and direction to boat speed and direction. minus mast rotation, in order to come up both true and apparent wind relative to the hull.

  Or, I think Rob suggested years ago having a shorter/thinner rotating mast on the windward hull that goes from the hull bottom, through the cabin top, and up into the air.  Put the speed transducer on the bottom, the compasses and directional sensors on the sides inside the boat, and the wind sensor at the top.  Or maybe it was Robert who was suggesting that. 

  If mounted in a tube with a waterproof joint at the bottom, you could even unplug the wires and haul the whole thing up a few feet in order to clean slime off the speed sensor without getting water in the boat.

  Then rotate the sensor mast 180 degrees when shunting (and only when you care -- you'll still get accurate apparent wind speed regardless).  There's no need for a rotation sensor because it's always assumed to be facing forward..
 

        - Mike

 

Rob : Agree that marine electronics in general and especially autopilots are way overpriced and rather crude.  They tout algorithms / fuzzy logic for maintaining course but they are actually extremely basic in their control sophistication. Some simple signal processing (to cancel out swell effects) applied to their control logic, never mind AI, would be a vast improvement but don’t get me started on that rant. B&G seems to be leading the way there (and charging for it)

Mike : After having owned Raymarine products in the past and having dealt with their customer service, I won’t buy Raymarine again. Period.

Also, anything that’s out on deck, in my view needs to be able to operate submerged in green water. Don’t like the idea of electronics way out there unless they are rated for that. Wire connections also tend to corrode, sometimes even if installed well. My experience with hydraulics has been very positive so far, simple, reliable and usually overbuilt for the task and very few parts that wear if any. If well installed of course!  Last one I had, I didn’t touch it for 10 years except to add a pump, zero maintenance, zero issues & was submerged several times. Pretty much everything around the hydraulics failed at some point (old boat) except the hydraulics and seastar helm.

“A single autopilot, but two directional sensors, one for each direction, with a toggle switch to flip between the two.” This sounds like a good idea; the shunting switch can switch both the pump and the heading sensor.

Agree on the features: wind vane mode is very nice, remote keychain control is fantastic single handed