Discussion in 'Big Boats' started by Bill Small & Lisa Grossi, Feb 8, 2018.
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Hi all, My 380 did not come with auto pilot. I hope you will share your successes. Many thanks, Bill
What other instruments do you have? Do you have a chart plotter at the helm? Are you planning on any offshore -- or are really outfitting for the Chesapeake? Etc. etc. etc?
Are you sailing short handed a lot? Do you have any budget in mind?
You need to look at a linear or hydraulic drive system. Your 17,000 pound displacement is beyond the ability of a wheel system to handle the boat.
Raymarine makes a EV200 system. Garmin, B&G, also have Systems that can handle your needs. Costs are about $2K. Plus install. It is an advanced DIY project.
We have a Raymarine ST7000 & Type 1 drive motor on our 1995 - 40.5 that is designed to handle vessels 20,000 lbs and under. I found that it is undersized for the boat, given that as with most owners we've added things that have contributed to weight gain over the years. I've purchased an EV400 system and a Type 2 drive motor that are rated to handle vessels to 45,000 lbs but have yet to get it installed. I'd purchase the system that will carry your present displacement and beyond to assure not having to do it again.
Thanks for your replies. We are cruising the Chesapeake Bay with new Garman chart plodder.
Bill & Lisa,
Following on John's and Karl's comments above, you will need a below decks autopilot because of the size of your boat. It is generally less expensive to use an electro mechanical piston autopilot vs a hydraulic one. The hydraulic units are more powerful (oz. for oz. - kw for kw), but I doubt you'd need to go there for what you're doing.
I think that the weight of the boat is not really as good a measure as the control surfaces efficiency (usually the rudder), the balance of the vessel (especially under sail), the sea states that you'll be sailing in, your battery and other electrical capacity and recharging system, and then weight, LWL, and so forth.
The "guidelines" that most manufacturers use is generally gives you a less expensive and underpowered system which is more prone to failure -- especially if you are really challenging the system under sail in a seaway and sailing with a lot of pressure. Sometimes, depending on the boat, it can even be a problem with motoring in tough seaways.
If your apparent wind and speed over water instruments are Garmin, I'd tend to go with that same manufacturer because the interface is less likely to be an issue. If you have Raymarine or one of the Simrad products for those instruments, I'd similarly go with them. The chart plotter will be sending information for purposes of GPS routes which is pretty generic.
I think that having an apparent wind function with a good autopilot really make a difference with shorthanding or on longer watches. There are differences in the quality of various manufacturers software and their ability to handle the impact of seaways, currents, variations in wind speed, the rudder efficiency, AND HOW YOU did or did not BALANCE the sails vs. the sea state & wind conditions.
I don't have any idea how efficient and powerful your rudder is, how you and your sails balance in the sailing conditions you're using them, and whether you really "get out there" in rough conditions and keep sailing. It's better to err on the side of over sizing, unless you have economic or electrical power constraints. In my "GUESS", that's one or two sizes up with electro mechanical for you. If you were going to be taking the boat to Bermuda or down to the Islands, then you might go up more, etc.
Usually you'd have a marine electronics firm install the autopilot and integrate the systems. The autopilot "piston" would likely connect to the steering quadrant on your rudder (unless Hunter has something odd).
The control head for the autopilot should be accessible from the helm; and, hopefully from the cockpit behind the dodger where you might be sheltered a bit, or trimming the sails. I think it a good idea to put multiple heads in so you can use the pilot to help you in situations that you might find yourself really appreciating the help while sailing the the boat or toughing it out in crappy weather or the unrelenting sun on a windless day.
If the Garmin unit provides for you to control the unit using the chart plotter at the helm, I would STILL HAVE AN INDEPENDENT stand-alone control head for the autopilot. I like redundant systems and controls.
Bill & Lisa here is a link to the Garmin website. Is gives you access to the type of system mentioned by SG.
I think what SG means about the rudder is, how balanced is it? None are perfectly balanced out of the shop but mine was too far unbalanced giving a heavy helm. A heavy helm will put strain on the steering gear, the autopilot and the battery bank, as well as the helmsman for long distant races. I balanced my rudder 18 months ago perfectly so even though my boat is loaded down to about 19,000 lbs, it could be steered by an old fashion wheel autopilot. I steer with 1 finger even at 8 knots with 20 degrees of heal and 8 degrees of weather helm when power reaching. I can let go of the wheel and it will stay put without the wheel break on. Now many do not like a helm like that for a few different reasons, but for a pure cruising aspect, it is perfect.
With that said, on my H376, which is very similar, was designed for a hybrid of a wheel and below deck: a rotary drive that mounts inside the console and attaches to the steering shaft via chain and gears in the back. The motor is 5 times bigger than the old wheel mounted motor and much stronger. Many Hunter dealers didn't use them and would cut away at the rudder shaft tube so they could mount a linear drive to the rudder post, but when I moved up from a wheel autopilot 9 years ago I went with the rotary drive (type 1). It was over powered at times with the default settings but after messing with the settings for a while I finally found I could make it perform much better but it still wasn't perfect until I balanced my rudder. Now it is a dream.
I think the method of measuring by displacement is because many boats do not have spade rudders so they are totally unbalanced and rely on the steering gear to take the pressure off the helmsman, but the below deck drives bypass all that mechanical advantage and bolt to the rudder post, so the heaver the boat, the stronger the drive needed to be.
I installed an autopilot on my 2005 Hunter 38 several yers ago.
Simrad autopilot AC12, RF 300 rudder angle, AP24 head, RC42 gyro.
I selected a JEFA linear direct drive, but needed to design custom installation on the bulkhead. All installed below but for the RF 300. Pictures avalable.
I am surprised some one has not shown the Raymarine drive 1 installed on the 38 and I will search my records to see I think I have something for the 38 from Hunter and will try my install on my 36
which just a idea how to help on the 38.
Our 1991 35,000 pound fully loaded P42 came with a below deck Autohelm ST-7000 linear drive electric autopilot motor, Course Computer and ST-6000 head. They still work after sailing several thousand miles. Shortly after purchasing Belle-Vie the fam got me a Garmin 178C Sounder GPS chart plotter, which I installed and connected to the ST-6000 head for route steering.
Under most sea states the autopilot does a fine job steering a course. Much of the time on a long leg I will merely use the steering brake to keep a course until needing a tack change. Then, as a solo sailor, the autopilot comes in handy to make that change.
Circumstances involved with blue water sailing become quite different compared to PNW protected waters. We have much shorter legs (35 miles very long), and will make a number of course changes before reaching our next anchorage. Seldom do we sail after dark, which would interfere with skipper's night where we must have time to slurp oysters, swill beer and commiserate about the day's events before a dinner of ...
Our 2008 38 was a dealer demo that we purchased new in 2009. It came equipped with Raymarime ST60+ instruments. It didn't have an autopilot on then but we asked the dealer to install one before we took delivery. They installed the Raymarime X10 with linear drive. It handles the boat which had factory displacement of around 18,000 pounds.
Unfortunately boat is laid up for winter so no pictures but they mounted the flux gate compass in the compartment under the head sink, the main computer is inside the seat at the nav table, and the drive arm is under the removable floor piece in the cockpit with the drive motor inside the stern locker on the port side
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