Choice of autopillot system

[p.hammar]

Dear Forum!

I have managed to collect some autopilot parts and need help in choosing what to keep and what to let go...

I have a 29 ft fin keeled sailboat that I am refitting for potential extended blue water cruising. It is an oe29, fairly easilly driven and light on the helm but can be heavy like many boats in following seas.

Through a series of impulse purchases second hand i now posess the following, all Raymarine:

One ACU 150 (s2) course computer
One SPX5 course computer

One ST6001+ controll head
One p70 controll head

Two fluxgate compasses

One rudder reference unit, Raymarine

Four mechanical activators, the type that is just a black cylinder with a stainless rod sticking out. These are in various states of functionality (i like to tinker with them) ranging from one that is useless because I let the ball bearings fall out, to one that is quite new and feels sturdier than the others.

I also have a windvane, and will make arrangements for the autopilot to also give steering signal to that, as an alternative. I will therefore have three steering modes:
Autopilot to rudder (no wind or when I dont want the windvane servo in the water)
Autopilot to windvane (when windvane struggles, or in light winds)
Purely windvane (hopefully a lot...)

To make things even more intrigate I must add that I have arranged for the mechanical activator arm to be mounted under my aft deck, connected to the tiller in a way so it is easilly engaged/disengaged. I dont like these to be exposed because they may take in salt water.


Now the question for me is which parts do i use to build up my system and which ones do I sell. Here my reasoning:

My number one alternative would be:
p70
SPX5
Fluxgate
Activator arm
This makes sense because as I understand the SPX5 is more modern than the ACU S2/150 and has Seatalkng as opposed to Seatalk1. I also hear that it has built in rudder reference and I could have one gadget less under the deck.

Second alternative would be
p70
ACU150/S2
Fluxgate
Rudder reference
Activator arm
This makes, perhaps, some sense because the ACU 150/s2 seems to be a sturdier piece of gear and is rated for heavier loads. It is, I understand, rated for hydraulics and can give out more amperage. This somehow feels like a good thing for ocean cruising.

Third alternative would be:
p70
ACU150/s2
Fluxgate
Rudder reference
Hydraulic pump and ram (which I would have to buy).
The ram could be installed so that i can easilly connect disconnect it for manual steering. Does his make sence at all? I doubt it but I am curious. Im thinking pump and ram should make for an extremely sturdy and strong autopilot, that would even take me through rough weather if my windvane fails, or when I want to give it a rest.

What about power consumption for the three alternatives? This is a major thing for me. I assume alternative 1 is the most power efficient, but sometimes we fool ourselves to think smaller thinks consume less. I also like to think that a hard struggeling mechanical arm with a dc motor will drain batteries more than strong hydraulics that do not have to be strained. But perhaps alternative 3 is outruled because a pump and ram consumes way to much, regardless of conditions.

Noise is allso an issue for me. Is pump and ram quieter?

Finally: control head: I keep assuming I should keep the p70 because it is newer and uses Seatalkng instead of Seatalk1. is there any reason for keeping the ST6001+ instead? Both look nice and seem nice to use. If the p70 has better fiunctions then that makes sence, but I am indifferent to the designs of them. Actually like the old no-nonsense digital display of the St6001+ and its rugged look.

Well there you go. Most thankfull for any advice. Oh, and it should be said i immensely enjoy playing around with all self steering systems and do not fear complicated arrangements. (I also experiment with sheet to tiller.)
Kindly
P.Hammar

[George_SD]

I only have limited experience with autpoliots, so will talk to the part that i know and that you have.

P70 is a good head and has two SeaTalkNG connectors on the back. This makes it easier to daisy-chain multiple devices within the same space. I would go with the P70 if you don't have any other old Raymarine equipment that you will want to interface with. If you have other older Raymarine gear, you will need a converter kit and more cables. At that point the older control head could make more sense.

Keep in mind - Raymarine is slowly moving away from SeaTalkNG specific connectors and are going with standard NMEA2000 on their latest MFDs and such.

[Boatguy30]

Put a tiller on it and get a Pelagic autopilot and spare drive unit. About $1100