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Old 26-03-2009, 16:40   #1
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Autopilot question

Meridian is a 38ft center cockpit sloop of 20,000 lbs displacement.(Irwin)
I am considering installation of an autopilot.
What do others have as an autopilot?? Do you use a "wheel pilot" or a below deck system?
Any comments would be greatly appreciated.

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go instead where there is no path........
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Old 26-03-2009, 18:18   #2
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"Wheel autopilots are toys"

If you want your boat to avoid broaching at sea going downwind and waves you NEED a below deck autopilot, preferably hydraulic. The pumpset motor should be as close to 300W rating as possible (1/4 hp).

Imagine how much power you have to put into the wheel to keep the boat on course in such a situation. No wheel autopilot has sufficient power or speed. In fact, a good autopilot may steer better than you can in bad conditions.

"I don't think there'll be a return journey Mr. Frodo". Samwise Gamgee
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Old 26-03-2009, 19:27   #3
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Below decks is much better

As Rick posts above, I think the below decks is best. An electro mechanical unit will work if you have it adequately sized. (The general recommendations that manufacturers use is often underpowered and under sized.)

The hydraulic units are usually much more robust.

What other instruments do you have (type, age, etc.)
Do you tend to change down on your Irwin in stronger winds (what's your sail suit)?
Do you tend to use a chute?
Do you anticipate using apparent wind functions?
Are you using the unit in easy LI Sound or generally sheltered waters?
Answers to those sorts of questions would be helpful to making the choices of equipment.
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Old 26-03-2009, 19:47   #4
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"Wheel autopilots are toys"
It may sound crude but it's what they are. On a calm day with gentle breezes the wheel pilot does a great job. With 30 knots off the port bow in heavy weather they fail but not right away. They lead you into thinking they will work then leave you to do it all on your own power.

It's time like these that the hydraulic below deck auto pilot works extra duty. If you have hand steered in these conditions a half day you'll be sore for weeks afterward. At least when you wrestle alligators you know it won't be long. It takes a lot of power on boats that are bigger than 15K pounds. We are only 18K and I know the difference hand steering vs the autopilot. Cruisers that carry wheel pilots usually carry a full spare and use it often. Below deck autopilots require good installation. There a re a lot of details.

We have a Raymarine ST7000 now and had a Simrad Robertson before on the last boat. Simrad is way better in the computer end of it. The adaptive nature of the Simrad software is amazing. The ST7000 has held course in 45 knots even if it was a short time. This is when you need an auto pilot. You don't always mean to be in difficult weather but if you become exhausted it sure is nice to have a backup.
Paul Blais
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37 15.7 N 76 28.9 W
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Old 26-03-2009, 19:50   #5
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I agree with Rick & SG. Wheel pilots are okay for light daysailing work, but that's it. I know several people who threw theirs overboard after they crapped out two days into a crossing. I had a belowdecks and basically drove the boat with it.

ComNav makes some nice units and has excellent customer service.
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Old 26-03-2009, 22:58   #6
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Originally Posted by Pblais View Post
It may sound crude but it's what they are. On a calm day with gentle breezes the wheel pilot does a great job. With 30 knots off the port bow in heavy weather they fail but not right away. They lead you into thinking they will work then leave you to do it all on your own power.
It sounds like Paul experienced that... I did too. Had to hand-steer 14 hours with 30 kts of wind on the North Sea when the Ray Marine (Autohelm?) wheel-pilot broke halfway on an up-wind trip. I had to give up and sailed back to England. It was not funny and I was close to needing medical care for my hands but just managed with some single malts... ;-)

It was just the plastic parts that broke, a toy is the best word to describe them.

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Old 27-03-2009, 07:27   #7
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We have BOTH on our boat. The prior owner was scared of the boat, and had a wheel unit put on, so he could steer the boat from his laptop.

Frankly, I've considered yanking it off the boat. It's a pain in the tail, just BEING there. The other unit is a Raymarine hydraulic unit.
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Old 27-03-2009, 12:07   #8
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On my first offshore trip (on a friend's boat) I was at the wheel when the Raymarine wheel pilot upchucked it's internal parts onto the cockpit floor. The thing just totally disintegrated. It wasn't blowing that hard at that point in the trip, either. I think a wheel pilot would be fine for motoring or motor-sailing in light conditions, but don't count on one for the heavier stuff.

I have a B&G Type 1 autopilot on my 12 ton displacement boat. It usually does a good job, but can labor pretty hard with large, quartering seas in heavy winds.
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Old 27-03-2009, 12:33   #9
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I have a 24,000# boat with a Raymarine linear drive system. You should have a below decks system, you can steer with the autopilot if your steering cable fails.

The linear drive is very smooth and has worked flawlessly for 5 years now. It steers very well in offshore conditions (we've used it in 40 knots of wind with fairly rough seas), and you really can't feel it at all when it's turned off. I know other people slag Raymarine, but mine has been very reliable and steers well.

If you are going any kind of distance, an autopilot is one of your most valuable crew members.

Get one with a wireless remote. Wonderful for dodging lobster buoys in the fog. Pay attention to installation, and don't set a toolbox next to the autopilot compass. If you have a chartplotter, you may want to inquire about compatibility and ease of interfacing the AP with the CP, and also with the wind instruments (mine is set up to steer either to course or to wind).

Good luck.
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Old 27-03-2009, 12:55   #10
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Not sure if want a unit with a lot of bells and whsitles or what. Consider the Alpha 3000. w/ Linear drive unit. They are basic, bullet proof and last forever. Been around over 30 years. Small company, call them on the phone. mechanical rudder disconnect available also. Alpha Marine Systems - Price List
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Old 27-03-2009, 15:46   #11
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I'll give a vote of confidence for the Alpha 3000. I've had one for 20 yrs and it's worked flawlessly and I have had no problems and done thousands of off shore miles with it. In fact, I use it so much that I only helm the boat when approaching and leaving a dock, or mooring.

What I like about the Alpha 3000:

1. It has a mechanical engagement with a teleflex / morse cable. This means that when mechanically disengaged there is absolutely NO friction or effect on the helm. It's as if nothing is attached to the steering system.

2. The mos fet circuit means it uses very little power - a good thing.

3. Setting a course is INTUITIVE and done with a large knob delineated in degrees. This is both like a helm AND a compass. since the indicator will point to the direction the boat is going. If you want to steer to starboard, rotate the knob clockwise. A very degrees of to tack turn it 100 or so depending on your boat. The pilot will move the helm hard over for "large" direction changes and so forth - like a helmsmen. The knob indicator can be easily read from a distance and is not subject to LED failures etc. It's a continuously rotatable knob. Mine is mounted such that I can look ahead, aft etc and turn the knob without having to fiddle with buttons or look at an instrument. This is handy when I want to aim at a mark for example. I turn the know and watch the bow as it turns to and points at the mark and then I stop. I can do this is small steps as well.

4. The unit has a YAW control which essentially controls how much correction the pilot will make. In flat seas the helm hardly moves, and you need very little yaw. But when the waves are pushing the boat around the pilot can compensate for each push off course and correct. Or with the YAW as MAX the helm stays fixed, uses less power and will respond the wave and wind forces without corrections. This is another rheostat with variable settings. Since the pilot is driven by a fluxgate, boat motion can lead to over corrections in the steering because of the level of damping of the compasss. You can find the right amount of helm corrections to save power and to not travel in a wavey track.

5. It has an auto trim feature which is supposed to learn how the boat behaves. I never got this feature to do anything so I never use it.

6. It cannot be driven by a GPS which means YOU have to set the course and YOU see the boat turn to that course. This means that if you steer from way point to waypoint you need to take the information from the GPS and turn the knob! I find this a safety feature rather than an inconvenience. And it hardlymakes sense to try to sail a course with many turns on auto. You would STILL have to trim the sails for course changes which is a lot more work than turning the little knob to the new heading. But when motoring with no sail trim you DO still have to dial the new course. Oh My!

This is a great pilot and I have no complaints. Make sure your fluxgate is properly mounted in the center of motion close to the waterline midship and not near any ferrous objects.

Mount the teleflex cable to engage and dis engage so that your can work the helm and use the teleflex cable. When you want to go to manual helm let the helm come to Center helm under autopilot, turn the pilot off. The helm is "kinda" locked in center helm position by the mechanical pin. Push the teleflex in to disengage and you are under manual helm. reverse the sequence to go from manual to auto pilot. It's important to engage and disengage at the same steering position and center helm makes the most sense.

Go for it!
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Old 28-03-2009, 19:14   #12
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Then again

1. I would never use a wheel pilot for off shore long range cruising, but a wheel pilot works fine for motoring in dead calm and for day sailing the Chesapeake at up to about an 18 knot breeze.

2. The newer RM units are geared instead of belt driven like the old ones. The belt driven ones broke a lot.

3. The wheel units are rated up to a 17,000 lbs displacement (at least the ones I looked at). So the OP shouldn't use one of these anyway.

The ST4000 that I have works OK for daysailing and motoring. Never tried it in a blow as I want to be in control (although I am rarely more than 4 hours from an anchorage or dock).
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Old 29-03-2009, 07:10   #13
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Displacement Ratings are very rough Approximations

Displacement ratings mean very little in the scheme of things.

How a boat balances, the efficiency of the control surfaces, what seaways you are in, and how much sail you have up (and it what trim) have a great deal to do with the load on the steering system.

I've been on 30' boats which are harder to stear than our larger boat with 3 times the sail plan and displacement. Yet if we have our almost 2,000 SF spinaker up and the wind starts to come forward and up-in-speed you suddenly take what requires a hand and bit of wrist action into a arm and shoulder experience.

In general, I've found that the recommendations of (say) Raymarine and even (our beloved B&G) are only a starting point.

There really isn't a good mechanical substitute for good trim and sense, of course. I think the best approach is to only ask an autopilot to do what you could with relative ease. If it starts to get too "hairy" and burdensome, then your autopilot is going to get you into trouble. You really need to trim down a bit. An autopilot can't see the wave ahead or behind -- while the algorithms of certain units (like the B&G Hydra) can make certain adjustments based on patterns wave patterns, these are not very sophisticated compared with a helmsman in a really challenging seaway. Your best defense is to balance the helm, trim, and adjust the speed to match what works for your boats control systems in a seaway.

On another note: Setting the Autopilot to Waypoint, or Apparent Wind, or Compass headings make things work very differently. Different units may adjust differently in combination with these settings depending on seaway conditions. In a moderate and unchallenging sea state it really makes little difference. BUT if things get hairy, you really don't want to put the pilot on Waypoint. If you think of the autopilot as an extension of yourself, you wouldn't want to "blindly" try and maintain a line without respect to the seaway and apparent wind.
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Old 06-04-2014, 05:43   #14

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Re: Autopilot question

does anybody know of an alpha autopilot service person around new england? thank you Andy
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Old 06-04-2014, 06:06   #15
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Re: Autopilot question

Andy Have you contacted Alpha.

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