How is auto-pilot used?

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jsc7

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How is auto-pilot used? Is it kind of like cruise control in a car, you sit at the helm and do not need to do anything but look out? Sort of like the auto-pilot in Tesla cars?

Are captains allowed to leave the helm with a ship on auto-pilot? That would seem kind of dangerous to me.
 
An A/P is a little different than a cruise-control, in that an A/P holds speed and compass heading. You can move around, but you still need to keep watch. Things can happen when you don't keep watch, like the boater in Puget Sound a while back. He set his A/P then went below to take a nap and had a meeting with a ferry boat. oops
 
Well, an autopilot can do several things. At its basic function, it follows any course (compass direction) that you set. Coupled with a chartplotter, it can follow a route or towards a waypoint that you have set on your chartplotter. Most waypoint following has the ability to dodge obstacles and then return to the course.

I use mine mostly to just follow a course. In open water, I can duck below to get a snack, but I first look around, note any traffic that might be a problem and if nothing is threatening for a few minutes, I will go down below for a minute or so.

I also use it to follow a tight ICW channel. This takes constant attention, adjusting course a few degrees port or starboard to stay in the proper position. But this is still easier than hand steering. I have a remote control head so I can sit back and make these course changes.

But when conditions get tight, like entering a crowded harbor, I always hand steer.

David
 
Greetings,
Mr. j. As Mr. mr posted, you are required, by law, to keep a constant watch while the AP does the steering (speed is set by throttle) on a programmed or set course. Our AP (Wood-Freeman 500) holds one set course only and cannot be programmed or interfaced with other electronic devices like more modern units can.
The more modern units can be programmed to change course at pre-set waypoints and take you from point A to point B without touching the helm but I have no experience with these. Wish I did.
 
Just an update on the above. AP will take a route (multiple waypoints) from a GPS and follow the route - however I believe that no AP will make the next turn for you. It will notify you when it is time to accept the next waypoint but, in case there are reasons the turn should not be made, it will not do it for you. That is certainly the case with my dual set up.
 
If so inclined, pull up the AP manuals on the Furuno or Garmin sites for some simple instructions and guidance. An AP will indeed make turns for you if so programmed and integrated with a plotter.
 
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RTF
The law requires an "Adequate Lookout", not constant, so there will be time, at trawler speeds, for a quickvisit to the head or to grab a snack. Before doing so, a thorough (adequate, remember) look around, to at least the distance that will be covered in the coming absence from the lookout, and, if safe to do so, away you go.
Course following on my Raymarine AP is better than just setting a compass direction, as it will compensate for cross track errors induce by currents, however it is sometimes a PITA as it will allow an accumulation of XTE to its own limit, then without warning, it will correct that XTE. If this were to occur when you are in a narrow channel or in a busy area that correction could easily cause trouble. For that reason, I usually just follow a compass course.
 
Keith makes a good point. It is "adequate" not constant. What is "adequate" is determined by conditions and location.

I generally don't use a compass course on my AP except for short periods (i.e. to hold a course while I set a fender or attach a line). If I am on a long leg, I will almost always set a waypoint and allow the AP to get me there. I also have a RayMarine system and the XTE settings are adjustable.

My AP behaves badly when it is first following a course set, but once it is on course it is almost flawless. I think part of its poor initial behavior (it wanders a bit before settling in on course) is that I don't have a boat speed instrument. I know my SOG (GPS) but not my speed through the water. This means the that the AP has less information to work with as it starts following a course.
 
menzies said:
Just an update on the above. AP will take a route (multiple waypoints) from a GPS and follow the route - however I believe that no AP will make the next turn for you. It will notify you when it is time to accept the next waypoint but, in case there are reasons the turn should not be made, it will not do it for you. That is certainly the case with my dual set up.
Click to expand...

menzies,

Actually, Simrad autopilots will execute the turn to subsequent waypoints up to a certain user-defined limit (I've seen 10°-30°), beyond which the user must confirm the course change. Garmin autopilots will make the turns automatically without any operator intervention at all. It seems each manufacturer/model might behave differently as it relates to these course changes. As always, RTFM :thumb:
 
95% + of all our boating is done with an Autopilot. However, we never leave one unattended or with no one on watch. That includes stepping below for a snack or to use the restroom or any other reason. If we need to take a break we have someone else take over and if there isn't someone else available, then we stop or idle long enough to do whatever we need to do. We don't continue at speed while not on watch. I know that's probably very much a minority view here of zero tolerance but when you create a grey area it seems to just keep expanding.
 
It also steers a straighter line of travel (compensating for currents and wind) than you are capable of steering by hand. It makes the most efficient use of your fuel by driving the boat in the most direct route.
 
We use it when trolling or open water cruising, really reduces the fatigue factor not always adjusting the wheel in a good sea. Must have a lookout all the time, my wife jumps in if I need to use the head or get a snack, good thing is the course is set so looking out for debris is the key.
 
BandB said:
95% + of all our boating is done with an Autopilot. However, we never leave one unattended or with no one on watch. That includes stepping below for a snack or to use the restroom or any other reason. If we need to take a break we have someone else take over and if there isn't someone else available, then we stop or idle long enough to do whatever we need to do. We don't continue at speed while not on watch. I know that's probably very much a minority view here of zero tolerance but when you create a grey area it seems to just keep expanding.
Click to expand...


I definitely understand your viewpoint and generally think it makes sense.

However consider this... Most of us are cruising with just two people on board. Most of us are cruising at 6-8 knots. Many of us are cruising in relatively open waters without the traffic density of say the ICW. Most of us are in boats that are 40' or less.

It takes me 15 seconds to leave the PH, go to the galley, grab a water from the fridge, and be back in the PH. And that is for a middle-age guy with two bad knees. That means that at my typical 7 knot cruise speed I have traveled much less than 1 boat length. I can make a cup of coffee in my Keurig in about 3 boat lengths (although I don't. I start the cup of coffee, go back to the PH and then go retrieve the coffee after it is finished so I am away from the helm for 2 boat lengths at one time and 1 boat length to retrieve the cup later.)
 
dhays said:
I definitely understand your viewpoint and generally think it makes sense.

However consider this... Most of us are cruising with just two people on board. Most of us are cruising at 6-8 knots. Many of us are cruising in relatively open waters without the traffic density of say the ICW. Most of us are in boats that are 40' or less.

It takes me 15 seconds to leave the PH, go to the galley, grab a water from the fridge, and be back in the PH. And that is for a middle-age guy with two bad knees. That means that at my typical 7 knot cruise speed I have traveled much less than 1 boat length. I can make a cup of coffee in my Keurig in about 3 boat lengths (although I don't. I start the cup of coffee, go back to the PH and then go retrieve the coffee after it is finished so I am away from the helm for 2 boat lengths at one time and 1 boat length to retrieve the cup later.)
Click to expand...

I do consider that. I also consider that while the likelihood is low, many things can happen on some of those trips away from the helm. Someone slips, someone gets burned by hot coffee. Now, your 15 second situation or three boat lengths isn't one that bothers me. You're never really out of view. The trip down steps to a head is one that I do consider a definitely "no". While not much can happen in 5 minutes at 6 to 8 knots, I would also contend not much time is lost by just pulling the boat back to neutral or idle. I would also contend waiting for the other person aboard to just walk up and watch in those circumstances is easy.
 
To the OP- On a boat if you set the throttle to a certain setting, the boat will maintain a very near constant speed. This is unlike a car, where hills and such would change speed if you held the throttle constant. So cars need cruise to adjust throttle to maintain constant speed. No such need on a boat.

The autopilot on the boat keeps you headed in a constant direction. If you left a boat rudder in a fixed position, the boat would wander one way or the other. This requires the helmsman to make constant small corrections to keep the boat going in the desired direction. The autopilot does that for you. It means you can do other stuff while moving and the boat keeps going the way you want.

The AP is one of the best inventions in the boating world. The slower the boat is, or the longer the trip, the more valuable it is.
 
I've heard the arguments against cruise control, that it takes your mind off your driving. It shouldn't. It should allow you to watch the roads instead of keeping your eye on the speedometer.

So, same with autopilot. It frees you to do all those other things you need to do at the helm. Makes it possible for you to keep better watch and keep an eye on all your surroundings.
 
dhays said:
I definitely understand your viewpoint and generally think it makes sense.



It takes me 15 seconds to leave the PH, go to the galley, grab a water from the fridge, and be back in the PH. And that is for a middle-age guy with two bad knees. That means that at my typical 7 knot cruise speed I have traveled much less than 1 boat length.
Click to expand...

1 knot = 6076 ft/60 mins = 101'/min
7 knots=707'/min in 15 sec travel is ~ 175', just saying.

Having said this, I have often left the wheel, while on AP, when there was no opposing (or even near) traffic. It was a fact of my previous (work) life. Done judiciously, I believe it is OK to leave the helm unattended for short periods, but you MUST know how far you are going to travel in the amount of time you intend to leave the helm.
 
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BandB said:
I do consider that. I also consider that while the likelihood is low, many things can happen on some of those trips away from the helm. Someone slips, someone gets burned by hot coffee. Now, your 15 second situation or three boat lengths isn't one that bothers me. You're never really out of view. The trip down steps to a head is one that I do consider a definitely "no". While not much can happen in 5 minutes at 6 to 8 knots, I would also contend not much time is lost by just pulling the boat back to neutral or idle. I would also contend waiting for the other person aboard to just walk up and watch in those circumstances is easy.
Click to expand...

I agree with you on both points. It is always possible that I could take a header as I go down the three steps from the PH to the galley and become injured. However, that is a risk that I'm comfortable taking.

With prostate cancer, I no longer have "quick" trips to the head. The couple minutes it takes is longer than my personal comfort level away from the helm at my cruise speed. So if my wife isn't available to take the helm (the boat is an amazing soporific for her), I will cut back to idle while I use the head. At idle under the AP the boat will maintain a couple knots of speed, just enough to maintain course. So I am still talking about only a few boat lengths. I have no problem cutting to idle for a couple minutes as it will lengthen my trip by even less than that.
 
dhays said:
I definitely understand your viewpoint and generally think it makes sense.

However consider this... Most of us are cruising with just two people on board. Most of us are cruising at 6-8 knots. Many of us are cruising in relatively open waters without the traffic density of say the ICW. Most of us are in boats that are 40' or less.

It takes me 15 seconds to leave the PH, go to the galley, grab a water from the fridge, and be back in the PH. And that is for a middle-age guy with two bad knees. That means that at my typical 7 knot cruise speed I have traveled much less than 1 boat length. I can make a cup of coffee in my Keurig in about 3 boat lengths (although I don't. I start the cup of coffee, go back to the PH and then go retrieve the coffee after it is finished so I am away from the helm for 2 boat lengths at one time and 1 boat length to retrieve the cup later.)
Click to expand...


Wow how long is your boat ? I did the math and it must be over 170 feet.
 
dhays said:
It takes me 15 seconds to leave the PH, go to the galley, grab a water from the fridge, and be back in the PH. And that is for a middle-age guy with two bad knees. That means that at my typical 7 knot cruise speed I have traveled much less than 1 boat length. I can make a cup of coffee in my Keurig in about 3 boat lengths (although I don't. I start the cup of coffee, go back to the PH and then go retrieve the coffee after it is finished so I am away from the helm for 2 boat lengths at one time and 1 boat length to retrieve the cup later.)
Click to expand...

7kts = 11.8 ft per second. 11.8 x 15 = 177 ft.

I suspect 7 kts is moving farther than you think it is.
 
ulysses said:
Wow how long is your boat ? I did the math and it must be over 170 feet.
Click to expand...

I could easily have failed in my math. Yup, looks like I was off by a large factor.

Quick estimate, about 6,000 ft per nautical mile. 7 knots would be 42,000 ft. 15 seconds at 7 knots would be 175ft or about 4 boat lengths?

See what happens when I try to do mental math before my second cup of coffee!
 
I find an autopilot invaluable for the reasons everyone has given. Like many of you, I will make a short trip to the galley at cruising speed, but a trip to the head is done at idle.

I used to have gps/route following autopilot on my sailboat. My current autopilot is capable but not wired for it. The big advantage of this feature in my experience is the ability to stay on the intended track. If I'm navigating through an unfamiliar area I will plot out a course and inspect the whole route at various levels of zoom on my charting software. In this way I build confidence that there are no hidden hazards in advance. This doesn't obviate the need to stay alert, but it does provide a safety net - if I'm on track then I know I have already checked that it's "safe." This is the approach I took coming back from Alaska.

To appropriate a well know axiom "the shortest route between to points passes through a buoy!"

Richard
 
We always maintain an adequate watch, but I prefer to steer with autopilot in all but the most dynamic situations. The AP holds a more consistent course with more gradual adjustments than I can. I actually think it helps me be a better watch, because I feel more free to really move and look all around. And if my heading is off by a tick or two, I can just nudge it over.
 
Autopilots are like having an extra person on the boat. It relieves the tedious steering. In the ocean, away from other vessels, it is possible to leave the wheelhouse for very short periods. But international/national law requires a present deck watch. In restricted waters, especially with other boats around it is dangerous to leave the wheelhouse.
That said, I use my autopilot all the time, everywhere it is possible. I hate steering having done 100s of hours. But I keep watch and am prepared to take the wheel.
 
Lepke said:
Autopilots are like having an extra person on the boat. It relieves the tedious steering. In the ocean, away from other vessels, it is possible to leave the wheelhouse for very short periods. But international/national law requires a present deck watch. In restricted waters, especially with other boats around it is dangerous to leave the wheelhouse.
That said, I use my autopilot all the time, everywhere it is possible. I hate steering having done 100s of hours. But I keep watch and am prepared to take the wheel.
Click to expand...

We always steered on the lake, many house, many days. If you told me on the day I was planning to cruise 10 hours that the autopilot was broken, I'd probably decide just to stay and have someone fix it, go tomorrow. I can't imagine right now steering manually for 10 hours.
 
When our A/P worked I often was alone on the boat. For coffee I would leave the wheel but since the coffee on the stove was two steps away and I could still see out and all around just fine there was never a problem. Only done after checking there were no other boats nearby.


If I had to go to to the head I killed the throttle into neutral. I didn't a couple of times and even at idle I was surprised how far the boat had travelled. Even though there were no boats about there is often lots of big wood and often prawn trap floats which can be troublesome.

Of course when my wife was aboard she would keep lookout so the boat could be allowed to continue. In heavy traffic areas/times I would hand steer.
 
BandB said:
We always steered on the lake, many house, many days. If you told me on the day I was planning to cruise 10 hours that the autopilot was broken, I'd probably decide just to stay and have someone fix it, go tomorrow. I can't imagine right now steering manually for 10 hours.
Click to expand...


I'm now a member of that church.

Conall
 
RT Firefly said:
Greetings,
Mr. j. As Mr. mr posted, you are required, by law, to keep a constant watch while the AP does the steering (speed is set by throttle) on a programmed or set course. Our AP (Wood-Freeman 500) holds one set course only and cannot be programmed or interfaced with other electronic devices like more modern units can.
The more modern units can be programmed to change course at pre-set waypoints and take you from point A to point B without touching the helm but I have no experience with these. Wish I did.
Click to expand...

Wow, you still use a Wood-Freeman 500. I had one on Freedom that lasted 35 years with no real trouble. They actually supported them until about 5 years ago. It finally died and I replaced it with a popular brand AP. That one lasted 3 years before I had to replace the "brain". The new one is great in that I can program it for a continuous series of courses but the WF was certainly bullet proof.
 
menzies said:
Just an update on the above. AP will take a route (multiple waypoints) from a GPS and follow the route - however I believe that no AP will make the next turn for you. It will notify you when it is time to accept the next waypoint but, in case there are reasons the turn should not be made, it will not do it for you. That is certainly the case with my dual set up.
Click to expand...

To clarify, an AP won't use multiple waypoints. It steers to one waypoint, and that is only a virtual waypoint. In reality, the chartplotter sends a bearing to the AP for it to steer, sends cross track error,(how far off in distance the vessel's current position is from the rhumb line that the chartplotter has determined from current position to the active waypoint), direction to steer (L/R), lat/lon, active waypoint ID and some other data depending on the chartplotter. The AP may receive the lat/lon, speed, or other data but it may not necessarily do anything with that data. The AP has an electronic compass or input from one, that it uses to determine heading, it typically sends that data to the chartplotter. Each AP uses slightly different variations but most are of similar function.

Simrad will make waypoint course changes contingent on a configured setting, typically a course change of less than 30 deg will be made without user intervention. Raymarine OTOH requires acknowledgement for each waypoint course change.

The reason a chartplotter using a route or even a single active waypoint is more accurate is that it continually adjusts the data sent to the AP to compensate for set and drift, something the AP is incapable of. Sure, the AP will steer a compass course, but it's a dumb setting, e.g. it maintains the heading, it just doesn't know where it leads to, so it can stay on the correct heading but end up way off the mark.

It's simply astounding how many cruisers are intimidated by the chartplotter/AP interface to the extent they won't utilize it; even more so how, when they finally get over the hump in the learning curve, they wonder why they didn't do it sooner!
 
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