Robust autopilot needed

[deblen]

M811xx specs
https://defender.com/assets/pdf/raym...54_install.pdf

[deblen]

More linear drive: https://www.cruisersforum.com/forums...ce-236041.html

[more]

best ever made electric raymarine type 1 or 2 you buy 2
Lecomble & Schmitt Linear Drive

[rgleason]

@deblen and @rslifkin
Agreed that the AP drive must be sized for continuous worst case use (ocean, wind, gulfstream, downwind) and that is when current use will be highest.
Regarding the power required for the drive, Paul Q. at PYI used a measured rudder drawing to estimate the load on the rudder based on rudder area.

With an AP drive the rudder is often restricted to 35 degrees either side. This reduces the turning force the rudder can apply. I have look that estimate up when at home.
However the point is that getting an ever more powerful AP drive is not a good allocation of money, because tge effectiveness of its power will be limited by the rudder size. I would not oversize AP rudder torque by more than 1.5. Then the money can be used for better and smarter controls.

[Plumbean]

Went through this same process four years ago. 34 footer, 12,000 lbs with an unbalanced rudder. I had very limited space, so the linear drives were going to be tough. I ended up with a DD15 (driving a below decks tiller arm on the rudder stock) and NAC-3. Someone above suggested the NAC-2 could run the DD15. I do not think that is correct unless something has changed. I have been very happy with this setup.

[Plumbean]

Originally Posted by rgleason

@deblen and @rslifkin
...
With an AP drive the rudder is often restricted to 35 degrees either side. This reduces the turning force the rudder can apply. I have look that estimate up when at home.
...

I don't remember the limits on the DD15, but I think they might be lower than 35 degrees. FWIW, I don't think you need that much range regardless.

[Cheechako]

Originally Posted by rgleason

Thanks so much, very helpful.


In answer to some of your questions.
1. Edson wheel steering, by quadrant and cable.
2. No servo pendulum wind vane yet. Mister Vee is under consideration. This would help save power, and perhaps be more effective in many ocean situations and will take some load off the AP and serve as backup too. This unit is not heavy stainless steel but is well built carbon fiber. I dont know if it will stand up, but I don"t want extra and unnecessary weight in the stern


The AP drive is the first question. Wheelpilots like EV-100 raymarine, are too lightly built and not powerful enough.



The Octopus RS and SD10 are similar and 180 kg torque. The DD15 is more powerful and is compact which is good, but it is also more expensive. This serves larger boats effectively in conditions I need, but is it needed for this smaller boat?


I will look at pelagic and consider pypilot or pelagic controls. I want a pretty sophisticated conteo that is rock solid and built for the environment. And will look up CPT alternate.


Thanks.

It's too bad they no longer make the Alpha 3000. Under deck quadrant with disconnect for when not in use. Durable, steady, recirculating ball aircraft drive. Simple and reliable.

If you want more than 35 degrees either side rudder angle you need to solve those problems, all you are doing is dragging turbulence like you're dragging a dumpster.......

[rgleason]

Raymarine Type 1 is suited for 22,000 lb displacement, lock-lock is 11 sec, and current use is 18-22 w.



I would need to find 30" under my cockip from the rudder post that is in the plane of the rudder tiller. I have just 24" to the rear, so I would nee 7" above the tank, otterwise I'll have to interrupt one of the lockers.

[rgleason]

Originally Posted by Plumbean

Went through this same process four years ago. 34 footer, 12,000 lbs with an unbalanced rudder. I had very limited space, so the linear drives were going to be tough. I ended up with a DD15 (driving a below decks tiller arm on the rudder stock) and NAC-3. Someone above suggested the NAC-2 could run the DD15. I do not think that is correct unless something has changed. I have been very happy with this setup.

@plumbean For our boat the DD15 or Jefa150 which is almost identical but I believe needs a rudder sensor, would fit under the helmsman, under the cockpit. Access to install it is via a narrow port cockpit locker which allows only one arm free to work. We are considering cutting an access port for partial or complete access. Do you feel the need or have had the for this on your boat? How is power usage in rough weather? Have you been in rough seas and high winds with following seas? Amps used? If so, how does it perform? Also, you are right, the Nac-3 is needed due to higher power requirements. Is yours a full keel?

[Salty Possum]

Pacific Seacraft 31. 11,000 lbs empty. I am happy with my current set up.

Cape Horn. 20+ years old and going strong.

A Raymarine tiller pilot used infrequently in place of wind control to direct the oar on the cape horn. Useful when wind is light and finicky or I am too lazy to get the trim right. I control it from the old Ratmarine wheel pilot control head

Wheel pilot came off because I repeatedly stripped gear boxes.

B&G T1 ram. T0 compact would have fit the parameters but the T1 fit and I was advised for my use parameters, much as yours, I should get the larger one. Awesome power. Indomitable steering running before the wind with too much canvas up in 50 knot winds against current in Gulf Stream with steep following seas ( I must like to suffer). . When I am putting on of my weight on the wheel and turn this thing on it takes the bill by the horns.

Tied directly to the quadrant with a 1/2 inch steel plate bolted into factory attachment points. Anchored into the boat with stainless angle sandwiched to 1/2in h thick and epoxied and bolted in.

Sucks a huge amount of power. I have never seen more than 14 amps on the monitor. I have Lithium batteries. Fine to sail 24-36 hours on it but usually for overnight and definitely multi-day I will use the Cape Horn. The Cape Horn will drag the ram in most conditions but it just takes a moment to reach back and slip the ram off the quadrant --the wind vane steers more crisply without that drag.

In my latest episode of bad weather judgement I lay in the Lee cloth down below and kept the boat running downwind in the T1 ram using my remote control and the feel of the boat. Awesome for a singlehander.

[FlyingScot]

Originally Posted by rgleason

@plumbean For our boat the DD15 or Jefa150 which is almost identical but I believe needs a rudder sensor, would fit under the helmsman, under the cockpit. Access to install it is via a narrow port cockpit locker which allows only one arm free to work. We are considering cutting an access port for partial or complete access. Do you feel the need or have had the for this on your boat? How is power usage in rough weather? Have you been in rough seas and high winds with following seas? Amps used? If so, how does it perform? Also, you are right, the Nac-3 is needed due to higher power requirements. Is yours a full keel?

According the DD15 installation manual found here: https://softwaredownloads.navico.com...0222303B_w.pdf
Average 2A consumption. The graph doesn't go above 15A as worst-case scenario.

NAC-2 is rated for 8A cont. and 16A max.
NAC-3 is rated for 30A cont. and 50A max.


Jefa lists the old Simrad AC-12 as acceptable. As far as I can find the AC-12 and the NAC-2 have the same exact Amperage specs of 8/16. https://www.jefa.com/ftp/steering/br...1-brochure.pdf


Me personally I think it would run on a NAC-2 but I don't take chances on the AP so we have the NAC-3, which is definitely overkill.

[Plumbean]

Originally Posted by rgleason

@plumbean For our boat the DD15 or Jefa150 which is almost identical but I believe needs a rudder sensor, would fit under the helmsman, under the cockpit. Access to install it is via a narrow port cockpit locker which allows only one arm free to work. We are considering cutting an access port for partial or complete access. Do you feel the need or have had the for this on your boat? How is power usage in rough weather? Have you been in rough seas and high winds with following seas? Amps used? If so, how does it perform? Also, you are right, the Nac-3 is needed due to higher power requirements. Is yours a full keel?

Mine is mounted under the cockpit similarly to how it sounds like yours would be. The install involved some extended efforts imitating Houdini, and at one point I nearly epoxied my hair to underside of the cockpit floor while building a shelf for the DD15 to sit on. I have not had to touch it since the install.

I have not made a concerted effort to measure power draw so I can't help there. I have had it out in relatively rough conditions, but mostly that was pounding upwind (25 knots with steep 6 foot seas). It handled that great, but that is not quite as severe conditions as you describe and my boat practically steers itself when close hauled. Keep in mind that the rest of your system will have a significant impact on autopilot performance. What sensors do you have for wind, heading, pitch/roll, bsp, etc.?

Not a full keel. Fin keel with a skeg hung rudder. S&S34, so early IOR style.

[Matt Johnson]

I've had both the Raymarine linear drive and L&S hydraulic. Both were reliable. But the L&S was noisier, used more power, and put a bit of drag in the steering system. I'll be putting a Raymarine type 2 on our new boat.

[rgleason]

The Raymarine linear type 1 has 75 kg-m and the Jefa LD100 has 100kg-m torque.
while the Jefa compact Direct Drive like the B&G DD15 has 150 kg-m. I was wrong about the Jefa Direct Drive and DD15, they both have built in rudder sensors.

[rgleason]

Plumbean,sounds like a very nice boat. Thanks for the install description and performance, it is very helpful for my decision. Our boat is well balanced upwind too, but does have a keel hung rudder.


What is your displacement?


Thanks Matt that is helpful..


Flying Scott good information on nac output thanks!