How Strong an Autopilot do I Need?

[Greggegner]

How much more is the heavier unit? Is the a down side to getting the heavier unit. I would answer those questions. If is doesn't cost must more why not get the bigger?

[donradcliffe]

Not to belabor the point, but you really need reliable autopilots with backups out there.

AMVER sihp saved distressed skipper
Juan Dario Zea Restrepo, the skipper of the s/y "Folly II" was rescued by the AMVER-ship "Kota Wangi" which was enroute Los Angeles-Aumel in the North Pacific on May 13, 2013 at 9 p.m. The mariner was in good condition. He got in distress while ransiting from California to Christmas Island when the vessel’s autopilot reportedly failed. After manually navigating the vessel for four weeks, he had become too fatigued to continue. Watchstanders in Coast Guard Joint Rescue Coordination Center Honolulu received notification of the distress from a Personal Locator Beacon at approximately 6:11 a.m. An HC-130 Hercules airplane crew from Air Station Barbers Point was launched and established communications with the mariner. A second Hercules was launched at 5 p.m. to provide cover during the rescue.

[Stu Jackson]

Originally Posted by brianb00

A good friend recently hit a bridge stanchion with a 50' vessel when the AP took a sudden turn to port. He grabbed the helm and in the ensuing attempt to over steer the AP he snapped the quadrant cables and bent the hydraulic arm on the very large RAM.

BB

Sorry to hear about that. I learned that bridges are mostly made of metal and that their vertical stanchions that hit and go under the water significantly affect autopilots. We also sail/motor over two underwater automobile tubes which also affects our autopilot. Big time.

[chala]

I am of the view that the force required from an autopilot ram to operate the rudder as more to do with the design of the rudder than with the displacement of the boat.

Originally Posted by chala

You seem to be handy with torque. The “JPEG” from Vetus should let you ascertain how suitable your rudder is to the ram drive. Some drive makers find the formula too conservative. I tested it and find it accurate.

[ullar]

Hello,

It's perhaps too early to ask but does anybody have any experience with RM new Evolution series? I'm very interested to hear any firsthand comments on those as I'm going to install a new autopilot system on my Amel Euros 41 in near future. I was actually vacillating between Simrad AC42 and RM SPX-30 course computers with 10T+ control units. Anyways, RM-s new Evolution adds a new variable to the equation.

There hasn't been any mentioning of NKE pilots here. They are expensive but supposedly the best pilots available.

[Journeyman]

Ullar, not yet, but an Evo-400 package is being installed this week on my valiant esprit 37 with a type 2 ram. I plan to go looking for a sloppy quartering sea state in gale force ASAP to shake it down. I am leaving a completely redundant Raymarine ST4000MKII wheel pilot in parallel as a backup and should be able to do a real world A-B comparison soon... bad weather permitting.

[colemj]

There would be no comparison between a wheel pilot and a 1980's below deck pilot, let alone a new generation below deck.

Mark

[Journeyman]

Mark,

The new Raymarine below decks linear drive type 2 Evo is in and the preliminary results versus the very old Raymarine ST4000MKII wheel pilot are not impressive.

Crossing Santa Barbara to Santa Cruz Island this month in 20 knots sustained at 60° AW and maybe a 3-4 foot 6 second swell/ wind waves, it was not appreciably better than the old wheelpilot.

Big 40° slews to leeward periodically off course. Bummer. Had hoped for better.

What was your rationale for it being better?

Thanks,
Journeyman

[forsailbyowner]

Originally Posted by Journeyman

Good input. Thanks.


We are installing the Type 2 drive now in anticipation of buying the new RM Evolution autopilot package to go with it (EV Sensor Core, ACU-400 Control Unit, and p70 Control Head), coming out next month.



Anybody got any installation anecdotes that resulted in trouble?

I would be cautious about buying new technology that hasnt been proven. When I purchased my state of the art unit it failed, when the technicians repaired it they installed new software as there were bugs in the original release that were the cause of the failure. It was all gracefully handled under warranty but it goes to show you they do tend to rush things to market.

As for using a larger than recommended drive unit? Im not familiar with the linear drives but with the hydraulic drive, using too large a capacity pump can result in a low voltage condition to the pump in certain load conditions according to furuno documentation. it can shorten the lifespan of the pump. again dont know it that would have anything to do with the linear drives.

[colemj]

Originally Posted by Journeyman

Mark,

The new Raymarine below decks linear drive type 2 Evo is in and the preliminary results versus the very old Raymarine ST4000MKII wheel pilot are not impressive.

Crossing Santa Barbara to Santa Cruz Island this month in 20 knots sustained at 60° AW and maybe a 3-4 foot 6 second swell/ wind waves, it was not appreciably better than the old wheelpilot.

Big 40° slews to leeward periodically off course. Bummer. Had hoped for better.

What was your rationale for it being better?

Thanks,
Journeyman

Well, I certainly cannot speak for the Evo - it is brand new. I can speak from experience with 3 different wheelpilots and many different below deck pilots - and there is a huge difference in performance, strength and robustness.

I can't believe that RM's below deck pilot is as bad as you are experiencing. They would not sell any of them if that was the case. I believe your experience, of course, but think something is wrong with either your AP or your setup. In the conditions and point of sail you were in, the boat should have almost steered itself.

On the other hand, I am skeptical of not having a rudder position indicator. Does the manual say how long the unit needs to "learn" your boat's characteristics? I would think the trip you took would be long enough.

I would talk to either the company that installed it or Raymarine directly if you installed it yourself.

Mark

[tropicalescape]

Originally Posted by forsailbyowner

I would be cautious about buying new technology that hasnt been proven. When I purchased my state of the art unit it failed, when the technicians repaired it they installed new software as there were bugs in the original release that were the cause of the failure. It was all gracefully handled under warranty but it goes to show you they do tend to rush things to market.

As for using a larger than recommended drive unit? Im not familiar with the linear drives but with the hydraulic drive, using too large a capacity pump can result in a low voltage condition to the pump in certain load conditions according to furuno documentation. it can shorten the lifespan of the pump. again dont know it that would have anything to do with the linear drives.

"Cautious about new tech" so true,I cant afford to be some companys test subject,give me the tried and true anyday(I will take a piper cub over any "new Tech" aircraft as an example ,80+ years and it is still the best thing going in small aircraft...)

[rebel heart]

On the other end of the spectrum, our boat weighs in at ~26k pounds and we've had an X5 wheel pilot for a few thousand miles. Still works. Windvane for sailing.

[Journeyman]

Hi Mark,

The unit was installed by Raymarine certified installers including a rudder position indicator. The leg where I experienced poor performance was about 3.5 hours, with the wind and chop gradually building over the first 1.5 hours. So plenty of time for it to learn the conditions.

The point of sail was maybe 30-40 degrees to the wave face, with wind gusting to 21-22 kts true, and sustained 19-20kts, at about 50-60 degrees AWA, one mainsail reef and a 140% roller furled to maybe 110%. So not the best airfoils and probably could have reefed more. Boat is 37 LOA, 32 LWL, 11.5 beam, 20,000 lbs, with 250' of chain in the bow.

The course was held most of the time, but after a lot of wheel action with the boat heading up in a gust and cresting a wave, it would be slow to correct as the bow then fell off to leeward some 30-40 degrees over about 4 seconds, and then it would correct back up to course, and do ok until it happened again.

I would take it off auto occasionally to gauge the weather helm by feel, and it did not feel really excessive for these conditions. Also, while hand steering I was able to busily correct ahead of time before the bow fell off too much, and keep from veering to leeward like the pilot was doing.

I only have about 400 miles on the new Evo so far and except for this one leg where I had high expectations, the conditions have been moderate at 10-15kts, mostly motor sailing, and easy for the Wheelpilot or Evo to handle.

I do like the relative silence of the Evo compared to the squeaky belt driven Wheelpilot, and I share your expectations that it will prove robust over time. But then so has my Wheelpilot.

I will discuss this with my installers and Raymarine. And read comments and advice here.

Thanks,
Journeyman

[colemj]

Originally Posted by rebel heart

On the other end of the spectrum, our boat weighs in at ~26k pounds and we've had an X5 wheel pilot for a few thousand miles. Still works. Windvane for sailing.

For motoring or light air, that wheel pilot is just fine on most boats. I bet it gives up the ship well before your windvane during tough sea/wind conditions. And well before a good below deck pilot.

Mark

[zeehag]

my simrad is very thrifty with electricity and as it is mounted on quadrant, is reliable more so than windvane or wheel mounted autohelm. i love it -- withstands 60 kt breezes easily and does a damfine job of steering with and without winds..
.i need no other pilot on my boat--is even better than a human.
my boat is light at 28000 pounds dislplacement--spozed to be 34000.

i would truly have a difficult time readjusting to that crappy wheel mounted systemless--it isnt good for cruising, but better for day sailing.... btdt and wasnt happy when i used that contraption--jumps off line when winds were over 15 kts and choppy water....very poor excuse for a pilot...the wheel mounted thing is good in flat water and no wind, whereas my quadrant mounted burly devil is reliable all the time.
i love it.