Autopilot Replacement

[osirissail]

Linear drive/hydraulic packages now come in a single unit with a ram to attach to your quadrant or tiller and a built in hydraulic pump and reservoir all in one unit. You hook up your DC feed wires to the unit and the motor drives the hydraulic ram that pushes/pulls on the rudder quadrant/tiller. There are many versions built by many of the major autopilot companies. And you can normally mix and match the various units with various autopilot computers.
- - Autopilots now come with a whole menu of fancy features most of which you will never use more than once. What you do use most often is the compass heading mode which simply holds the boat on a heading you select. For this feature to be best utilized you need a "rate gyro fluxgate" rather than a simple "fluxgate". Fluxgates are solid state without an internal "floating compass". As you start a turn to a new heading every fluxgate/wet compass will start to turn in the opposite direction. The rate gyro fluxgate senses this and prevents the heading information from feeding this "opposite direction" information to the autopilot computer. That's the theory, anyway.
- - The feature that hooks into your wind direction instruments is worse than useless in most cases. The little wind direction vane at the top of the mast is normally swinging and moving all over the place due to wind variations and mast swings. If you want constant wind angle sailing buy a real windvane for your transom.
- - The "navigation" feature is nice but can really get you in trouble as it will steer the boat according to the route and GPS information you have entered in your navigation system computer. The autopilot will attempt to constantly keep you on your plotted course line which with moderate seas and varying wind will result in constant autopilot "grinding" to turn the boat. But the big "brown you pants" moment with the GPS navigation mode occurs when you have entered double waypoints on top of each other. At the waypoint the autopilot will attempt to turn to the hidden waypoint usually resulting in a 180 degree turn just when you don't expect it. Talk about a Mexican circus as sails, booms and crew dash about trying to figure out what is happening. If you are entering a harbor when this happens, it really gets exciting/terrifying. It takes supreme discipline and carefully route entry procedures to prevent this.
- - So you end up with the "compass mode" being the most used. Try to find a reputable unit with solid history of "just working" and has a good "rate gyro" fluxgate option. I use the Simrad Robertson series units primarily because of their reputation as solid, just keep working, units.

[Highlander40]

For me the compass mode is just about useless, except as a temporary place holder untill I get a waypoint plugged in. I guess that I could compare the heading made good to the compass and enter a correction.
That number however changes all the time depending on wind and current.

The boat determines the best control mode, I have no keel or rudder so the route line is the most stable refference.

As far a "grinding" goes the control should have different settings for the activity level of the drive. A full keel sailboat can run with a 1 setting instead of the 3 setting I use. You wont be spot on but you won't be on the rocks either.

Double waypoints? Don't blame the unit for your lack of effort. Electronic navigation requires just as much care and attention to detail as the old paper charts.

Learn it, use it, love it

[lancelot9898]

Originally Posted by osirissail

" I use the Simrad Robertson series units primarily because of their reputation as solid, just keep working, units.

I installed a Robinson/Shipmate unit back in 1991 and it has worked well enough until several years ago when I took a near lightning hit. The EMP knocked out the battery charger, the VHF, SSB antenna tuner, the radar and the auto pilot. Everything has been replaced/fixed with the exception of the auto pilot which is on the "to do list". Since Simrad has taken over the Robinson/Shipmate brand when I get the time and money, I'll probably just replace the computer and gyro compass leaving the existing hydraulic ram if the Simrad people concur. I never did use the auto pilot under sail, but relied upon the monitor wind vane instead. Under power is when the auto pilot came into use and I never was able to get a straight wake out of it no matter how I adjusted the feedback. It always put me on the mark, but a long S curve stood in my wake. Maybe the newer units will eliminate this problem?

[osirissail]

"Highlander" >> The boat determines the best control mode, I have no keel or rudder so the route line is the most stable refference.<<
Very true, but what kind of boat has 'no keel and no rudder'?
- - The Robertson under Simrad is the same quality solid unit and is primarily sold to work boats and fishing boats and other big heavy boats. In fact you can save significant money if you buy the components listed for a "work boat" versus a recreational sailboat. As with everything, recreational boats normally pay a premium over the "regular working folks."
- - The "rate gyro fluxgate" came out in response to the constant wandering present with an ordinary compass system. It smooths out the constant "dancing" around by an ordinary compass especially in a bouncing or high speed operation. And of course, it is more expensive but well worth the extra money. And, the autopilot response rate can be adjusted to a setting which is a compromise between constant rudder movement which sucks more power or to less frequent corrections which saves power when operating only from batteries. A little more "wandering" save significant amphours. You can adjust the autopilot to whatever is best for you.
- - Just about all the autopilots have a menu selection for operation below 7 kts and operation above 7 kts.
- - My hydraulic ram and reservoir are original from a previous WH installation and are 40 year old. The work fine with the Robertson computer and a new hydraulic pump. The Robertson is also "signal compatible" with Furuno equipment which is a bit plus as my Furuno radar can get signals directly from the Robertson computer versus having to go through a NEMA transfer box.

[Highlander40]

osirissail-- AH,, my boat draws 22" and has water jet drives.
Yet I cruise and go far from home. Go figure.

[osirissail]

"Highlander" Wow, that is some boat, at least the sister-ship's I saw on the web. I think maybe you should go to New Mexico and get an autopilot out of a F-18 Hornet fighter jet. It is probably the only system that can keep up with your boat.

[Highlander40]

good point. The pump does work pretty hard and with 23,000. nm on the clock, I am wondering how far it will go.
Just for fun- the average speed based on engine hours is over 15 kts for the life of the boat, 10 years.

Life is too short to own an ugly boat.

[robgoh]

Originally Posted by s/v Thea

Hi Mike,

I replaced my alpha 3000 on my Stevens 47 with a Raymarine SmartPilot X30/ST70. Still using the alpha elec drive for now. Haven't used it a lot but very happy with it so far.

Doug

Hi Doug, just wondering how did you connect the X30 to the direct drive of the alpha? Are they compatible? Would you know how much power the entire autopilot system draws, say on average cruise or continuous use of the drive. My current system is the Alpha 3000 but it is playing up a little. It is very old and came with the boat that I purchased not long ago and I think it is time for a replacement. I am at the cross roads of changing autopilot system and any advice would be most appreciated. Thanks,

Rob

[forsailbyowner]

I'm happy with my Furuno Navpilot. Only glitch is with interfacing with an older Garmin 192 chartplotter. When I check tides or look around on chart it starts beeping with degradation of nav data message. Holds course well, I like rotary knob course adjustment and smart auto that compensates for currents without a waypoint. dodge function is handy for going around crab floats. All in all thumbs up.

[hpeer]

I have elsewhere WH autopilots are very good. I will eventually need to install a autopilot on our 44' (very) heavy cruiser with chain/cable steering. Long deep keel with keel hung rudder. I would prefer something simple and rugged. No existing autopilot so I am starting from scratch.

Suggestions?

[s/v Jedi]

The quality of the WH pilots is good, but they are not very advanced. The hydraulics they use are commercial/industrial standard components that are strong and reliable. It is these hydraulic drives that give WH pilots their fame.

I like Simrad Robertson a lot; it also has it's roots in commercial fishing like WH Pilots but it is also technically advanced and includes sailboat features. Like said, the weak part of many AP's is the hydraulic drive and the options from Simrad/Robertson ain't any better than the others.

If you already have hydraulic steering, this isn't a problem because you only need an extra pump and those are reliable. For rack & pinion or Mamba steering you can get a motor that engages a gear in those systems which is very reliable as well. But if you have cable & quadrant steering, you will need to add the full hydraulics option and it would be best if you use components for hydraulic steering and add just the pump from the AP manufacturer.
Many sailors do not understand the huge difference in quality and reliability and order those complete electric/hydraulic kits from the AP manufacturer... either because the dealer tells them to do that or because it's the easy thing to do or they don't even think about alternatives. It means hand steering & costly repairs later. Components for hydraulic steering (cylinder/ram, reservoir, valves, hose) are readily available so it's not a problem to create something solid instead.

When we installed the Simrad/Robertson, we connected it to the hydraulic drive of the WH Pilot which works perfectly.

The Furuno navpilots are very good and so similar to the Simrad/Robertson that I think they are the same internally (either oem'ed or cloned). That smart auto mode is an example that I only found on these two pilots, plus they look the same.

ciao!
Nick.

[nautical62]

The motor on my Raymarine stopped functioning properly after only 150 hour of use. Very frustrating.