Autopilots, favorites, dynamics, boat type ?

[Eyrie]

This is from my boatpartner Tom Condy regarding the current autopilot system that we have on the Hawkfarm 28, 5700 lbs disp.

-Synthia


I sure did enjoy reading Rob's harrowing story of getting caught out in a nasty storm in his old Beetle. Wow. The ocean wants to kill us mariners sometimes.

Summary: The Raymarine A/P that Synthia put on Eyrie is pretty good for the boat. I'll try to summarize the good and bad.

At first, the system consisted of an ST4000(?) above-deck tiller pilot w/a linear drive unit, and a brain inside the single display instrument; there was a separate fluxgate compass. The brain accepted NMEA input from the interfaced Nexus wind instrument.

This system performed so-so for 2 years (including 1 DH Pac Cup, 1 season of SH sailing). I remember that it was "ok" in the moderate breezes and seas but had considerable trouble, mostly downwind, in larger seas/winds. One time, it steared the boat with the kite up and a reefed main, on the return leg of an SH Farallones race. At the islands and 10kts of breeze, it was fine. As we approached the ship channel, the winds increased to the high teens/low 20s, the quartering seas built over the SF bar. The A/P was barely maintaining control as it S-turned
somewhat wildly down the course. The kite eventually blew out, but the A/P still kept general directional control, but not confidently. I mostly used the A/P in the Heading mode.

Synthia then upgraded to the ST6000 SG1 (?) system. This had a rudder reference, an instrument display, and a separate box with the brain and rate-gyro. Overall, it was pretty easy to install and use. This system worked vastly better than the previous, mostly because it could deliver
more "human-like" tiller control. Synthia used this on the SH Transpac. I used it on a LongPac, a Spinnaker Cup race, and a SH Farallones Race, all with the spinnaker, but all mostly in moderate conditions.

The main improvement is that in tough conditions, the S-turn amplitudes are significantly reduced. Since the A/P now has the tiller deflection and rate of turn inputs in addition to the data it had before, it can better determine the tiller corrections needed to steer the boat on-course (or wind-angle). It might also have an improved algorithm
(with hysteresis?) for some limited 'learning' of the boat's handling characteristics relative to the A/P's tiller moves. As a result, the A/P's performance is less varied, more predictable, uses less power, makes more efficient tiller moves. This lead me to have far greater confidence (and comfort using) the unit.

The areas where it had trouble were in lighter winds (< ~8 kts), especially if the seas was lumpy/sloppy, in both Heading and Wind Angle modes, but more so with the latter. It would often get off course because it didn't have enough steerage and/or the lumpy seas would slew
the boat (bow or stern) enough that the alarm would sound. This can be very annoying, but you can often try a few things to balance the boat better or counter the lumpy seas better such that it would steer better (in compass mode; could also try playing with the configuration settings
(gain, yaw, sea state? ).

I tried playing with some of the configuration settings, but only occasionally. Mostly, the more sensitive/reactive you configure things, the more the A/P moves the tiller. And since the linear drive unit is really noisy, it's bothersome. This also would use more power. Thus, I was balancing power usage and noise parameters against A/P performance; not ideal.

I have not used the system in super nasty/rough conditions.

So, I think the Raymarine product is above average, but not outstanding. And if it is one of the cheaper solutions at $2500, then it's likely a pretty good deal.

Here is a list of other misc good/bad things that I can think of:

GOOD
----
* Easy installation
* Easy to use and understand controls, configuration
* Easy to read display/instrument with good lighting (and level control)
* Pretty good all-around performance
* Competitive Price (you can buy 2 systems (1 for backup) for the price of just 1 of the other vendor's systems.
* Pretty low electrical power consumption
* Interface to NMEA works
* The ST6000 is sized for boats 2-3 times the displ/size of Eyrie.
Oversize your A/P.

BAD
----
* Doesn't do so well in light air/lumpy seas.
* The system is electric.
* Very noisy drive unit (every change is a loud grinding sound)
* The linear drive and control cables had to be protected from the SSB/HF interference
* The rudder sensor (another ram-like rod assembly) has to be ganged with the linear drive unit. This is a little hokey looky, but it is solid. We had a little sunbrella jacket made for it to keep out big water/spray.
* The brain's circuit board was not conformal coated for moisture protection. I sprayed on a layer myself. Overall, the components are only light -to-moderately built. (consumer grade and not commercial grade).
* I wish I had the wireless remote control unit ($600 extra). Would save you from having to run to the instrument panel whenever you needed to control the A/P.

In your own case, you should decide how much singlehanding you are going to do and for how long you are going to own your boat. If the answers are "a lot" and "forever", then splurge and go with the best (NKE, B&G, Alpha). You can afford it, deserve it, and you'll enjoy it. If the answers are "a little" and "less than 5 years", then consider a more modest A/P investment.

[seabird51]

As an alterative to the extra gasoline genrator consider the small Kubota single cylinder diesel engine mated to a large alternator. My setup weighs under 400 lbs total, uses 1/8 gph and puts out 50-70 amps @24v. the other requirements are some space, plumbing and $. On SHTP's I ran main engine about 1 hour per day and had no solar or wind charging.
Lou