Autopilot Principles

D

Donald Tyson

Member
Would someone have a few minutes to explain the mechanics of an autopilot such as would be common to use on a CD22 or 25 with usual outboards like most of you have. Are they electric powering hydraulic? are they reliable. I'm simply unfamiliar with both the wiring and mechanics of these devices. I see them on West Marines Webpage. Is it something one would want on a C-Dory?
 
Hi, So autopilots ( AP) come in several forms for several uses. auto pilots for the big motors are either hydraulic or electrical. 95% are hydraulic driven by a pump that is mounted inline with your current hydraulic pump, thats your steering wheel. Your steering wheel is just a hand powered pump. you turn it and it drives fluid. The Ap will be a electrically driven hydraulic pump. Electric auto pilots drive a worm gear that moves the ram that turns your motor. an example is the new yamaha 250 and up motors that have a built in electrical driven ram to turn the motors.

So these "main motor auto pilots" are great for lots of stuff. Its a lot of work driving a boat in big swells of for long periods. Using heading, course or plotted routes all make driving easier and less stress full. Even on long hauls on smooth days its a lot less work and you can be doing more of the other thing you are suppose to be doing in the boat, looking out the window. In fog or just bad vis its a a lot easier for the boat to hold the heading then while you look for logs and other boats then it is for you to do both. Holding a heading in the fog is a bitch some times when you cant see 30 ft. and you spend all you time looking at a compass.

Auto pilots can be used at all speeds. I liked to us mine in the 22 when i had it. They are also great for use while trolling for salmon and other fish. Much less stress if the ap if driving the boat while you rig up and set downrigger or fight a fish or even net your fish. That is the thing I miss the most on the 27 not having a autopilot.

Which leads us to auto pilots for the kicker only. There is only one on the market right now just for the kicker. Its a old TR-1 which got a remake and upgrade into the Garmin reactor 40. The big plus of this unit is that it will control the throttle of your auto pilot as well as direction all from a control head, handheld remote or your MFD depending on how you rig it. Lots of different functions. Too many to list here . Lots of tube you videos to watch on that. but its the hi gold standard as far as I can tell Nothing does everything it does or as well but its just for the kicker or trolling motor. Not big enough to run the main.

Well those are the basics as I see it. so question one is always " what do you want to do with it"
 
My last C Dory was the only one which had an autopilot. Most of my other boats, I sailed in long distances in a straight line--the ideal for an autopilot. My rational with the C Dory was I was on ICW, Rivers or lakes where I was making frequently course changes. Most of my early sailboat auto pilots were mechanical, either rack and pinion, to a tiller, or chain drive on the same drive system of the main steering (cable and chain. There would have to be some form of a clutch. The hydraulic did not need this. On our long distance cruising boat, the autopilot did over 95% of the steering (average 10,000 miles each year at 6 - 7 knots.

My very first pilot was based on the chassis of a Norton Bomb site used in bombers of WWII. It had parallel tungsten wires on the compass, and there was a center contact on afloating compass needle. The boat'c course "hunted" over a band of about 8 degrees. That would drive realays, to power the motor port of starboard. These all had direct drive, reversing 12 volt motors. Later early. pilots used a varuabke shaded disc or polarized light to give proportionate flow. One pilot worked all of the time in a severe storm, with seas over 35 to 40 feet. It was an oversized unit designed for a boat twice the displacement of our 35 tons. We carried a spare light bulb, and circuit board.

Fast forward to C Dory with a Raymarine Autopilot. Now we have GPS, a heading sensor, all axis sensors, which correct for heel, pitch and yaw in the boat, so the pilot is not constantly hunting. Most of the modern autopilots on C Dory sized boats, have a hydraulic. auto pilot. After starting you can either put in a magnetic course or outline a course on the chart plotter, puting in "waypoints" where the pilot makes a correction to the next leg of the course. The computer is one part, and the brains, which sends a signal to relays--and most all have solid state switching (drive helm to port or starboard) via which way the hydraulic pump is pushing the fluid in the hydraulic ram to correct course. Many of modern pilots can hold a course +/- one degree. The drive motor takes a lot of current--in larger pilots, this may be up to 30 amps. C Dory sized; 5 amps or so.

There used to be a follower, a sensor on the ram which indicates how much the rudder or motor has moved. Now this is done virtually by the computer.

For me one of the advantages of the pilot is to allow me more time to have eyes on the water and other boats ahead, rather than constantly watching the course. Ideally there should be no effect on the wake, the rudder moves a very small amounts. The boat shoud not be "hunting" or going side to side, making a straight line course. I often used the remote to "dodge" debris, or chage the course, so we didn't come too close to another boat.
 
Okay I feel much more informed and will know what I'm looking at my more clearly when I'm in the buying process and/or when I install such a device.
I hope to utilize a kicker in Canals and IWC. Do you all use Autopilot there, in those narrow spaces, as well? Or is the mapping not really that accurate?
 
IME, based on where I use my boat, having an autopilot would not provide much utility. Between channels, canals, shallows, other boats, and the like, I have to be paying attention to where I'm going and what everyone else is doing. So I might as well be steering the boat. Only on occasions where I am out on larger expanses of open water an autopilot might be nice to have, but these instances are not very frequent.

Yes, there are autopilots and nav systems that will do auto routing to follow narrow bodies of water and avoid shallows, but then you have to watch them closely to make sure they don't screw up or miss a turn.

Just my $02. Your use case may be different.
 
So not a high priority for you.
Perhaps I was thinking too hard again but there are some areas I'd use it if I have it and now I better understand how it works. Still, I wish I had a Norton Bomb sight.
 
hope to utilize a kicker in Canals and IWC. Do you all use Autopilot there, in those narrow spaces, as well? Or is the mapping not really that accurate?
Click to expand...

Why do you want to use the kicker instead of main engine? Some canals and narrow bodies of water can have currents, rivers empty into them, also tidal entrances, to the ocean or lake etc. Steering with a kicker is a bit trickier than with the main engine. If you need reverse or a fast, get out of the way--coming around a bend, then the main engine would be where you want to be going.

Most charts these days were accurate when printed--remember that NOAA charts, corrected are not sold, even thought the digital ones should be accurate. There are often shifting channels, and these require local knowledge, such as from the Great Loopers, where persons send in corrections daily--Active Captain also used to do that. You also want to access the Local Notice to Mariners. LNM. This has a daily log of changes to waterway, lights, beacons, wrecks. Way back in ancient times, the chart distributer (For example South West Instruments in San Pedro Ca.) would hand correct the chart to the latest LNM, with india ink on the chart before they rolled it up to give to you.
 
I'll want Quiet. Additionally I'll want to save fuel. I can accomplish both by using the 9.9 kicker. I pushed My 28' 4ton Pearson all over the Chesapeake and Jersey Shore with a 6 horse Johnson. never had an issue though in traffic you need to think ahead further. From what Ive seen of the Erie and Champlain canals a kicker would be appropriate If at hull speed. I'm betting these little boats will respond well. The only negative I see is there may not be enough juice coming off that little motor to re-charge the batteries.
Thoughts?
 
Don,

While boat shopping, I’d advise not letting autopilot (or radar) be a dealbreaker. Either can be added later (with more current technology) should you decide it’s important to your cruising style. Either can be several thousand dollars (new with installation) and the market will allow your seller to mark up his boat price accordingly.

However, I’d suggest paying a premium for a newer outboard engine. Hours alone don’t tell the whole story…Years ago Bob posted an article about big Yamahas used daily on a Charleston commercial boat with 8,000 hours on them. Yamaha reps tore them down and found them to be in better shape than most lightly used engines, although they were never even flushed at the end of the day.

Especially in FL there are outboard dealer repair shops that refuse to look at engines over a certain age…sometimes any over 10 years old. Our shop owner won’t touch any engine built before 1995, and that’s the oldest I’ve heard of in FL. They don’t advertise this, but they’ll ask when you call wanting service. Especially in saltwater, old bolts seize up and break off, and at $130/hour it’s just not worth their time or yours to pay for fixing that or the other structural stuff that is almost worn out.

Agree with Bob that there is no place on the NY or Canada canals appropriate for using a kicker rather than the main engine for the reasons he cited. The speed limit for the NY system is actually 10 MPH (except at marinas etc) which is in the RPM range (2,000 for us) where ‘wandering’ is no longer an issue like it is at 700 RPM. You won’t ever save enough gas money to be worth it. And if you don’t fish much, you might not need a kicker. If you want a small dingy engine, Steve Baum collects and repairs the 2 strokes that are much lighter to handle but can no longer be made under EPA rules.

Hope you find a great boat that fits!
John
 
John,
this is interesting. It was my impression that planing speed on, lets say for example, a 22 is 11mph. So to get up on plane and settle in to a nice reliable planing speed you'll be at 15mph. Am I close?
Then on the canals I'll be at displacement speed which is 5 or 6. Any faster it is a waste of fuel. That is where the kicker will shine....displacement speed.
Here is how I look at it: I'd be a heck of a lot wiser to take the advice of a couple of old salts, just to be on the safe side. Then when fish beckon I can troll in open waters for dinner using the kicker.
Huh, and I thought I was on to something, lol.
On the subject of Radar and Autopilots they are not on the list unless the boat I find already has them on them.
John I never thought about the age of engines to be an issue to the degree you speak of. Thanks for that warning. I'm hoping for a boat in the 2002 -2008 realm. Engine age may become more of an issue.
 
Donald, on my 25, I found that running my kicker full out to get my hull speed of 5-6 mph, I was actually burning more fuel than just running a slow rpm on my main. I'm not saying this is always true, but in my case, I was better off just running the main at hull speed. Now if you are trolling, or going slower than hull speed, yeah, then the kicker will save you fuel. And my main is actually quieter than my kicker when running slow.

Regarding Radar, I do a lot of boating on the Great Lakes, and have had to get back in fog. I've also been in fog on some Rivers. The radar is nice. But make sure you use it in the clear as well, to learn what you are looking at. :wink:

The Autopilot has also been almost a necessity when going on long cruises, rather going fast or slow. Especially on my 25, which steers a lot stiffer than my 22 did. It's also nice to have when trolling solo. Colby
 
I like to know what the outboard use pattern is. If the boat is used every so often, and then let to sit on a lift or trailer and not be flushed, there is a risk of corrosion, and some very serious issues. If you use that motor every day or even 24 hours a day as some marine patrol, or harbor masters do--then that engine may be in great shape with many hours.

Not that long ago, a close friend bought a C Dory 25, that I had advised him not to buy, because I knew that the boat's Honda was not regularly flushed. The engine looked good, the owner started it, and it ran--my friend did not ask for a sea trial. "If it starts and runs it must be fine;" Fast forward several weeks and I get a phone call--"We took the boat out for the first time and it overheated only a short time after I ran it cruising speed". --he took to the nearest OB shop, and the mechanic pulled the thermostat and said the engine was full of sand...Nope the engine had not been run in shoal water. After further investigation it was determined, that This was mostly corrosion, and sodium The engine was just barely getting cooled at an idle.

There are also specific engines to look out for corrosion and even holes in major water passages. Some times this is a bad choice of metals, some times it is a design flaw. Some brands seem to corrode more others. If you take all proper precautions, then the chance of problem is minimal. You can ask the party you buy the motor from, but he may not know about previous owners.

Donald asks about low planing speed--it depends on a number of factors, including boat weight- (ready for a month's cruising 100 gallons of fuel and 30 gallons of water, plus many extra repair items can add over 1,000#). Motor height, boat trim, prop, Permatrim foil or not. altitude, sea state, condition of the bottom etc.

I went through most of my life on "slow" sailboats, but I also owned both dinghies which were slow, and ones which were fast There were plenty of times to see the scenery at 6 to 8 knots. My average days run when cruising, such as crossing the Atlantic was 175 to 185 miles under sail. This had a huge impact on where you could go, especially in high tidal range areas--such as PNW, both inland passage through British Columbia and S E Alsaka. You try and go through a passage at high slack water, or high water with minimal turbulence. We saw vessels as large as 60 feet capsize in Seymour Narrows when an inexperienced skipper made the mistake of transiting other than high slack. This cost one crewman's life. Going thru "narrows" or similar take not only planing, but some degree of seamanship. With the C Dory, you can often go through 3 or even 4 set of narrows because the boat's speed, and how it handles.

No not a lot of power (12V), But you can run a small honda generator with a battery charger to charge the batteries. The Honda 1000 can run the 5,000 BTU window AC from Walmart. Run an induction burner etc.
 
I've been on and off water for years. But I've never learned so much about boating until I met Loopers and C-dory owners. I'm very grateful.

The countdown has begun for Us. Our boat fund should be ready by Feb. We're also going to Hontoon. We hope to have a boat soon after. A 22, 23 or 25 will do nicely. By that time I should know a lot about the boats and also about how to utilize them and benefit from their unique characteristics. The first year will be a series of shakedown cruises on weekends (Wife still works). Probably Cape May to Albany in steps.

Thanks for patiently explaining things. I consider you folks, and most C-Brats to be vital and sort of a Core Group for our further adventures.

Tom mentioned YouTube and the internet are great resources but I like to bounce things here first because your experiences are specific to my brand.

Bob, is it safe to run the Honda while underway? The 2000's are all over the internet right now, I assume they're stollen since there are so many. 400-800$. I've had them at different places of employment for 40 yrs and they don't quit.

Thanks.
 
If the "Hondas" are "new" I would be very suspicious. The current model is 2200, and it is worth the extra. As you say, "keeps on running". I have one which is over 40 years old.

There are copies??? Some of the clones seem to be fairly good, for light use.

I have occasionally run the generators under way, but be wary of "Station Wagon Effect". Also have several CO detectors, one at your head level when running, one on the bunk level. I don't run them when we are asleep. Since we have been cooking with induction (Florida ambient temperature issues.) Before dinner is a good time. I used a battery charger which "forced charging"--especially with the Li batteries; Could charge with 50 amp specialized charger.
 
Is it necessary to ground these generators when running onboard? I'll be getting into this once I have the boat. We, being older, will need juice to be comfy when in port and there is no breeze cooling us. I don't tolerate humidity well.

Seems to me that the Honda is about the best backup one could have when the motors aren't being run and the sun isn't shining. But I've heard rumblings about safety and I guess that is related to C O.
 
Donald Tyson":19u2k6o0 said:
... Seems to me that the Honda is about the best backup one could have when the motors aren't being run and the sun isn't shining. But I've heard rumblings about safety and I guess that is related to C O.
Click to expand...

I use a Honda 1000 when I want to use an 120v AC unit and there is no shore power available. This is when the boat is at anchor. When moving there is usually enough airflow through the cabin to be comfortable (even in Mid Atlantic summers). The issue with moving with the AC on is more due where the AC sits (in the center window) than where the generator is (on the swim step).

For battery charging I use the main engine at high idle (~1000 rpm) this charges the battery at a much higher rate than the Honda gen and the onboard battery charger. Usually 20-30 minutes before bed is sufficient to recover the evening's drain on the battery. I have two batteries. One is used and the other is held in reserve for engine starting (if necessary).
 
Donald Tyson":j5tqej98 said:
I didn't know that a battery could be charged by the engine that fast. Amazing.
Click to expand...

Depends on the engine. Newer Hondas have large alternators. My engine usually puts about 30 amps into the battery at 1000 rpm (if the battery will take it).
 
Don,

You’re not likely to find a new legit Honda 2200 for under $1100.

https://www.ohiopowertool.com/honda-pow ... -companion

I believe, based on Mark Elwell’s experience with a Companion model, that one has a 30A shore power compatible plug (no adaptor required) and that unlike the 2000, it will start and run a 15,000 BTU rooftop Coleman like we have.

Portable generators have a ‘floating’ ground; don’t try to ground them.

A few boats will trigger the Reverse Polarity LED on your AC circuit panel, if so an online ‘cheater’ plug should fix that. Get the theft prevention steel handle bar, otherwise any thief can cut the plastic grab handle with a hacksaw even if it’s chained to your boat.

Honda is very clear that their products are not designed or engineered to be used on boats (or much else). See Jim Healy’s AGLCA website for his observations. Make a cardboard mockup to how much room it takes up and where you’d store it. Agree with at least two CO detectors, Time Weighted Avg models have less false alarms.

Another option is very efficient 12v RV fans with solar panel, two burner Coleman stove for cooking and percolator coffee and heating basin bath water; grand total under $300.

Typical batteries with a typical Danfoss fridge will last at least one night at anchor. With no solar, you can run the engine at fast idle and charge up enough for another night with careful load management, which you’ll learn quick.

Happy Thanksgiving to all!
John
 
One question I’ve always had about AP was how does it react when you grab the wheel? Can you steer around an object and then let go of the wheel and allow it to get back to its path or do you need to reset it?
 
Back
Top