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#1
posted to rec.boats.cruising
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"Roger Long" wrote in
: Any tips or experience interfacing and using one of these autopilots with a GPS also appreciated. -- Roger Long The autopilot doesn't do the navigating. The chart plotter does the navigating and sends out directional messages to the autopilot via the network from its calculations taken from GPS position data. i.e. "We want to go to this waypoint. We are headed in this direction, so we need to turn the boat 48.5 degrees to starboard to head that way. Our course over ground to the waypoint shows there is 1.8 knots of current trying to drag us off course, so we need to subtract that from the boat heading. Yo! Autopilot! Turn 44.5 degrees to starboard or I'll tell the captain to replace you!" Autopilot, terrified of being turned into marine scrap, comes about smartly 44 degrees to starboard, as measured on its compass I'm convinced, causing an awful gybe because you got cheap and didn't buy the network wind instrument so Chart Plotter could tell the slaves it needed to gybe to the new course. The chart plotter makes constant course corrections and tells the autopilot what to do to make it happen. Autopilots aren't all that smart, if you haven't guessed that already. All this is to force you to buy more boxes...GPS boxes...Chart Plotter boxes...Speed boxes...Gyrocompass boxes...Compass boxes...Wind boxes...etc. The more boxes, the more data. The more data, the smoother that turn is because Chart Plotter and Autopilot can see their rate-of- turn lots more often than waiting on the calculated ROT from the slow GPS updates. The more boxes, of course, the more profits. Boats are full of boxes... Hope the gybe didn't pull apart the traveler that needs replacing....(c; Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. |
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#2
posted to rec.boats.cruising
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"Larry" wrote in message ... "Roger Long" wrote in : Any tips or experience interfacing and using one of these autopilots with a GPS also appreciated. -- Roger Long The autopilot doesn't do the navigating. The chart plotter does the navigating and sends out directional messages to the autopilot via the network from its calculations taken from GPS position data. i.e. "We want to go to this waypoint. We are headed in this direction, so we need to turn the boat 48.5 degrees to starboard to head that way. Our course over ground to the waypoint shows there is 1.8 knots of current trying to drag us off course, so we need to subtract that from the boat heading. Yo! Autopilot! Turn 44.5 degrees to starboard or I'll tell the captain to replace you!" Autopilot, terrified of being turned into marine scrap, comes about smartly 44 degrees to starboard, as measured on its compass I'm convinced, causing an awful gybe because you got cheap and didn't buy the network wind instrument so Chart Plotter could tell the slaves it needed to gybe to the new course. The chart plotter makes constant course corrections and tells the autopilot what to do to make it happen. Autopilots aren't all that smart, if you haven't guessed that already. All this is to force you to buy more boxes...GPS boxes...Chart Plotter boxes...Speed boxes...Gyrocompass boxes...Compass boxes...Wind boxes...etc. The more boxes, the more data. The more data, the smoother that turn is because Chart Plotter and Autopilot can see their rate-of- turn lots more often than waiting on the calculated ROT from the slow GPS updates. The more boxes, of course, the more profits. Boats are full of boxes... Hope the gybe didn't pull apart the traveler that needs replacing....(c; Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. I'm pretty much of the opinion that the only automated course correction on a sailboat, under sail, should be "Steer To Wind." That doesn't insure that you will go where you want to go, but it will help prevent the boat suddenly deciding to tack or gybe because it reached a waypoint that you forgot about. Of course, missing that waypoint turn might put you aground, but under no circumstances should the boat be allowed to sail itself for any length of time without supervision -- fall overboard and the boat continues merrily along its way. I use my tillerpilot on Essie, but only with someone keeping an eye on "Otto." If I'm singlehanding, I have a remote for "Otto" that lets me make corrections from the foredeck. |
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#3
posted to rec.boats.cruising
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KLC Lewis wrote:
I'm pretty much of the opinion that the only automated course correction on a sailboat, under sail, should be "Steer To Wind." All my steering under sail will be done by the Cape Horn windvane servo pendulum. The small electronic unit will just tweak the servo shaft while under power with the primary effort to turn the rudder provided by the boat's motion, just as under sail. -- Roger Long |
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#4
posted to rec.boats.cruising
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"Roger Long" wrote in message ... KLC Lewis wrote: I'm pretty much of the opinion that the only automated course correction on a sailboat, under sail, should be "Steer To Wind." All my steering under sail will be done by the Cape Horn windvane servo pendulum. The small electronic unit will just tweak the servo shaft while under power with the primary effort to turn the rudder provided by the boat's motion, just as under sail. -- Roger Long Ya, Cape Horns are good units. I want to figure out how to add one to my boat, but with my davits it's a bit difficult. |
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#5
posted to rec.boats.cruising
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"KLC Lewis" wrote in
et: I'm pretty much of the opinion that the only automated course correction on a sailboat, under sail, should be "Steer To Wind." That doesn't insure that Lionheart's Network Pilot (B&G) has 3 options...Steer to Network Wind instrument's data, steer to the autopilot's compass or take instructions from one of the chartplotters or The Cap'n. I agree steering to wind is correct, ESPECIALLY at night sailing short handed. We never let her go off by herself without someone on watch. Most of her sailing controls come back into the cockpit under the hardtop. Sticking to a waypoint course isn't practical in most sailing situations we encounter. Sailing in the general direction of some waypoint is nice, though...(c; If anyone is in a hurry or has to "be somewhere" at a certain time, please take a jet, not spoil it for the rest of us who are happy to get there "some time this month". Thanks.... Beer - Check...Food - Check...Water - Check. Who cares who's first? Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. |
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#6
posted to rec.boats.cruising
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"Larry" wrote in message ... I agree steering to wind is correct, ESPECIALLY at night sailing short handed. We never let her go off by herself without someone on watch. Most of her sailing controls come back into the cockpit under the hardtop. Sticking to a waypoint course isn't practical in most sailing situations we encounter. Sailing in the general direction of some waypoint is nice, though...(c; If anyone is in a hurry or has to "be somewhere" at a certain time, please take a jet, not spoil it for the rest of us who are happy to get there "some time this month". Thanks.... Beer - Check...Food - Check...Water - Check. Who cares who's first? Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. I've charted-out my proposed route for my wee-long July cruise around the northern end of Lake Michigan. In theory, it's seven days leaving Marinette (home port), hitting Washington Island, Snail Shell Harbor at Fayette MI, Manistique MI, St.James Harbor at Beaver Island, Leland MI, Stugeon Bay via the Canal, and back to Marinette. In theory. I'll be gob-smacked if that's where I actually get to go. Karin |
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#7
posted to rec.boats.cruising
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"KLC Lewis" wrote in message ... "Larry" wrote in message ... I agree steering to wind is correct, ESPECIALLY at night sailing short handed. We never let her go off by herself without someone on watch. Most of her sailing controls come back into the cockpit under the hardtop. Sticking to a waypoint course isn't practical in most sailing situations we encounter. Sailing in the general direction of some waypoint is nice, though...(c; If anyone is in a hurry or has to "be somewhere" at a certain time, please take a jet, not spoil it for the rest of us who are happy to get there "some time this month". Thanks.... Beer - Check...Food - Check...Water - Check. Who cares who's first? Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. I've charted-out my proposed route for my wee-long July cruise around the northern end of Lake Michigan. In theory, it's seven days leaving Marinette (home port), hitting Washington Island, Snail Shell Harbor at Fayette MI, Manistique MI, St.James Harbor at Beaver Island, Leland MI, Stugeon Bay via the Canal, and back to Marinette. In theory. I'll be gob-smacked if that's where I actually get to go. Karin That should have been "weeK-long," but the way weather can blow up here, "wee-long" might actually turn out to be prophetic. :-D |
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#8
posted to rec.boats.cruising
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Larry wrote:
The autopilot doesn't do the navigating. That's not what the manual for the ST1000 says. The GPS can tell it the bearing, distance, and track error. The ST1000 has a logic circuit to resolve this into a new heading. No chartplotter on my simple boat. Not enough room and power for all that fancy stuff. I'll only be using this under power as well. See other reply. Enjoyed the rest of your post though. -- Roger Long |
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#9
posted to rec.boats.cruising
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"Roger Long" wrote in news:45c39114$0$1339
: That's not what the manual for the ST1000 says. The GPS can tell it the bearing, distance, and track error. The ST1000 has a logic circuit to resolve this into a new heading. Like I said, the chartplotter tells it how to steer the boat. A GPS receiver puts out lat/long/time and calculates course and speed if it has a little display with a crumb line. You can tell the simple GPSes with simple displays what waypoint lat/long you'd like to go to and it will make a waypoint IT can steer the autopilot to. There's no way to input a waypoint lat/long into the autopilot that has a few course change buttons and simple controls. $GPAP data coming from the simplest GPS tell it what to do: $GPAPA - Autopilot Sentence "A" $GPAPB - Autopilot Sentence "B" $GPASD - Autopilot System Data So, the little GPS you put the waypoint into is the chartplotter, whether it has a $200 map plug into it or not. The autopilot has no computing capacity to store waypoints, do great circle calculations, etc. On your simple installation, I'd like to recommend the Garmin 76Cx handheld GPS/Chartplotter in its little snapin mount at your helm. Power is not an issue. It uses so little it will still give you full navigation on its own batteries if yours fail. It comes with America Recreational chart, but the CD has all the bigshot charts you can load into its standard microSD 128MB memory card. The CD program loads the 76Cx from your laptop, and you activate the charts you want to BUY online for it. Now you have a full-featured chartplotter to run the nav solutions and tracking on that's really neat. I installed one on my buddy's sailboat, and he also has a Jolly Boat (fiberglass rib boat with 40hp outboard). We bought a second snap-in GPS mount for the Jolly runabout and you just pop the 76Cx out of your pocket into whichever boat you're on and have a full navigator, even on a boat with a 40hp Yamaha outboard....overkill?.. (c; The little autopilots I know of only have a fluxgate compass to steer with. Larry -- Democracy is when two wolves and a sheep vote on who's for dinner. Liberty is when the sheep has his own gun. |
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#10
posted to rec.boats.cruising
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Larry wrote:
On your simple installation, I'd like to recommend the Garmin 76Cx handheld GPS/Chartplotter in its little snapin mount at your helm. Power is not an issue. Exactly the one I bought my boatpartner for Christmas. Great minds think alike. I hadn't thought of it as a chart plotter but now that you mention it, it really is. I bought a micro SD card with my new cell phone last year and got a 1 gig card because that was all that was on the rack. I've gotten tired of making crappy looking videos and pictures with the cell phone so I switched. The GPS is now loaded with every street map from here to Florida and out to nearly the Misissippi. I went to Washington DC last month and I would still be driving around in circles if I hadn't taken the GPS along. I thought the Thunderingly Stupid Agency might get weird about my taking a GPS on the plane but they were more concerned with confiscating my 1 OZ, factory sealed, travel size mouthwash bottle because it wasn't in the plastic baggie that is supposed to slow down a terrorist enough for the cabin crew to jump on him. Even when I missed turns, the Garmin just recalculated and gave me a new line to follow back to my route. A ten buck card reader writer from Radio Shack makes loading and unloading the maps faster and easier. The street maps even have the dirt road into my family's summer cottages so 2 gig card (the largest it will take) should handle every chart I'll need to get from here to Newfoundland and back. I bought this unit because it is the same size as the black and white 76 I also have but my aging eyes need the color. I'd alread built this mount http://home.maine.rr.com/rlma/Strider0601.htm#gps for the old one so I didn't shop but it was a good choice. -- Roger Long |
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