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Old 08-02-2011, 16:53   #16
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Originally Posted by CarinaPDX View Post
Alchemy - I agree with your points. I would point out that I had no issues with setting up my system in terms of hardware problems. Calibrating the compass took some computer savvy which might be beyond some but I wouldn't consider it a big issue. If electronics and computers are not your thing, and you don't have a friend who can help you, then this would be a stretch for many.

I agree with the desire to keep independent instruments. The trade-off is with the value of integration. Sharing information increases the capability of most modules. These networks are isolated so I'm not worried about a problem somewhere on the network taking out everything else (lightning excepted). I have found the GPS to autopilot connection useful but agree that it is also a potential disaster if not used with great caution. As for redundancy, I try to put in as much as possible. My computer can be used with its own GPS and OpenCPN and nothing else, or I can connect it to the N2K bus and 0183 inputs. All of my communications gear shares another GPS and is isolated from all other instruments, the MFD has a dedicated GPS, and the AIS has its own GPS and display with crude world chart. Barring a problem with the GPS system itself I feel I am pretty well covered - but of course I have paper charts, trailing log, swung compass, sextant, etc. I could buy MaxSea to display radar on the computer as a backup to the MFD - too low on the list for now. BTW I don't see the open source software as sufficient to use a PC as a proper 2nd station yet, although it covers a lot and is being actively developed.
Yes, I've just started with OpenCPN on a netbook, however, and it looks promising.

We seem to be of the same mind. The GPS/autopilot linkage is primarily a problem for me because it a) might take you to an ill-advised waypoint too close to a hazard, or one not on your chart, b) or the GPS might lose its fix, causing a crash gybe (assuming if under sail), and c) I just think it makes the temptation to go below and cease active looking around, a bad choice in my view.

Autopilot on a given bearing, from fluxgate or sat-aided compass, seems a better idea to me when under motor. You just have to hope your heading isn't directly over a sunken tanker of iron ore, is all.

For sailing, a properly adjusted windvane has huge advantages in terms of energy saving and has been shown to work as well as an AP averaged over hundreds of sea miles. It doesn't care if you sail over a giant magnet, and a glance at the compass heading tells you if the wind has changed.

Slaving the AP to the windvane just seems nuts to me...but people do it. Then again, I figure the installation of airbags in cars has made a generation of worse drivers who no longer think they can be killed in car crashes...
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Old 08-02-2011, 18:30   #17
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Not against mixed integration but right now the software isn't there , that's my view.

Garmins have bad autopilot integration, ray is bad with video audio simrad great audio iPod sound and switching interfaces , furuno good radar .

In practice to get the best put of each systems software you have to stay within the family

Dave
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Old 08-02-2011, 18:36   #18
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Or just do the integration in your head...
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Old 08-02-2011, 18:55   #19
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Or just do the integration in your head...
Sit on the throne and plot courses......sorry toilet humour!

Thansk everyone...this is a good thread for information....

Keep it coming...

Mick
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Old 08-02-2011, 20:09   #20
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Alchemy- Yes, we seem to be in agreement.

Connecting the autopilot to a GPS is a real issue. I like that following a track to a waypoint (basically steering the autopilot by the cross-track error) can nicely deal with leeway, but the risks are substantial and a close watch must be kept. There are just too many ways one can get bit doing this. One of the nastier failure modes happens when the GPS shuts down and the autopilot continues on its way without any warning. I still think it is useful, just not a substitute for a good watch. I have tried route following a couple of times; now that is scary! Just a bad idea.

I have probably run the autopilot more without the GPS, and indeed have had it go walkabout because of local magnetic disturbances. There is never a substitute for a good watch...

I completely agree about the value of a windvane. However I have to disagree about your criticism of an autopilot steering through a windvane (if that is what you meant). I have a Hydrovane that drives a trim tab on the transom-hung rudder, which is a very powerful system. Still, in little or no wind it stops being able to steer. In such cases I will often connect the autopilot to the trim tab in order to reduce the load on the autopilot. This saves electrical power but also extends the life of the autopilot (steering a barn door rudder with an 18" tiller really stresses the autopilot). I break them often enough as it is...

Half way across the Atlantic my trim tab broke and I had to resort to the autopilot on the tiller. I was shocked - it only broke once. But I was able to repair it from other parts. In the past I have kept 3 autopilots on board; the main autopilot, a spare, and a completely separate one. I am down to just one at the moment. Needless to say I am not impressed by their reliability.

BTW using a wind sensor as input to the autopilot isn't nearly as useful as it first seems. The autopilot still steers by the compass; the compass heading is gradually modified when the average wind direction changes. No way the autopilot responds to gusts the way a windvane can.
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Old 08-02-2011, 20:53   #21
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For a new installation you really should install a N2K backbone using the devicenet components. Then, if you want to connect a device which use non-standard cabling but is otherwise compatible with N2K (SimNet, Seatalk-NG etc) just use a drop-cable that adapts to the appropriate connector on the device-side.

Most of the equipment is a no-brainer I think... wind, gps, compass all Maretron sensors. Depth/Speed/Temp the Airmar DST-800 (also available from most other brands under their own name... from Furuno you get a 5m drop-cable while Airmar supplies it with a 2 meter cable..).

Now, you have a N2K backbone with all the basic sensors connected and data flowing. This will work with Furuno, Simrad, Garmin etc.

Imo, best radar/plotter is Furuno, best Autopilot is Simrad (Furuno sells same devices under own name I think; also, the drive units work on every brand, no need to buy a so-so drive of the same brand as the rest of the pilot). There should be enough choice for N2K AIS now and also VHF (Simrad, Garmin)

When you buy a Simrad autopilot, you probably already get a Maretron compass with it. It also comes with N2K rudder angle sensor. Connect these to your N2K backbone like any other N2K device but use the adapting drop-cables.

Hopefully your AIS will also have a GPS and supply that data on N2K bus as a backup data source.

Instrument displays: Furuno (their new color display is great), Garmin and of course Maretron (the best but $$$) are all good choices and connect directly to N2K, as does Raymarine ST70 which should be stable too nowadays.

cheers,
Nick.
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Old 09-02-2011, 02:43   #22
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For a new installation you really should install a N2K backbone using the devicenet components. Then, if you want to connect a device which use non-standard cabling but is otherwise compatible with N2K (SimNet, Seatalk-NG etc) just use a drop-cable that adapts to the appropriate connector on the device-side.
Its a point of view, depends on the level of mixing of equipment. The Rays cabling is useful in that it also carries Seatalk as well as Nmea2K, and the connector shell is designed for small spaces.

Quote:
Imo, best radar/plotter is Furuno, best Autopilot is Simrad (Furuno sells same devices under own name I think; also, the drive units work on every brand, no need to buy a so-so drive of the same brand as the rest of the pilot). There should be enough choice for N2K AIS now and also VHF (Simrad, Garmin)
I really think that objectively thats not true anymore, Panbo has researched a lot of the newer SD UhD radars and its hard to call a winner. All are more capable then the average user needs.

As to autopilots, from a money/perfromance perspective its a long time since Simrads autopilots are up there with the best. Robertson used be the leader but Simrad have slipped. Rays is very good, Garmins new one looks very promising, especially from a price point of view.

Simrad can be difficult to get service support in many out of the way places.( thyats my experience).

Its worth pointing out that Garmins autopilot actuators are custom to Garmin and the controller cannot drive other types of actuator.

As to instruments display , the GM10 is by far the best price/performance unit. ( though some of the displays need more attention) followed by the ST70 and then the Furuno RD33. ( certainly based on European pricing models.). The aspect ratio of the RD33 screen in my opinion leaves a lot to be desired.



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Old 09-02-2011, 05:35   #23
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Hi Dave,

I agree with you, but please keep in mind that I looked at it in absolute terms of what is a "best" unit, not using price as a factor.

I never read anything about anyone not agreeing that the Maretron 250 color display isn't the best etc. They are also expensive so price-performance numbers might put them at a lower ranking. I think it's good to start with looking at what is best (very good) without price as an issue and work from there because many components might not cost that much more.

Simrad did not let the Robertson APs slip. They were just so good that not much could be improved (the only improvement was making every part N2K compatible) while the rest have been catching up with them. The drive units are the weak point for any system and this is what needs the most attention while buying an autopilot (we use a WH Smith dual drive unit).

ciao!
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Old 09-02-2011, 08:39   #24
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as a comparison
Based on inboard pilots , and small rams

Furuno $4000
Garmin $3500
Simrad $3400
Ray $ 2500 ( x10, linear arm)

given teh proven performance of Ray pilots thats a remarable difference.
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Old 09-02-2011, 14:11   #25
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I think it appropriate to note that there are really 3 categories of autopilots. You seem to be talking about the below-decks models that drive the quadrant (and may be electrical or hydraulic). The above-deck wheel pilots are a different category. And the tiller pilots are the third area. Raymarine seems to be the last to offer a wheelpilot; they work but I have never been impressed by their reliability. Raymarine and Navico/Simrad are the only remaining tillerpilot manufacturers; none of their products are up to steering a cruising boat for the long haul. To their credit, as this has become abundantly clear, they have reduced the maximum recommended boat size but this doesn't solve the problem - it just covers their liability.

I wish I could use a below decks unit. The competition has served well and there are a number of good solutions with modern interfacing. If one of these vendors would only produce a tillerpilot that was up to the task...
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Old 10-02-2011, 15:48   #26
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given teh proven performance of Ray pilots thats a remarable difference.
I assume you mean "proven price-performance" of the Ray pilots... I've had nothing but trouble and broken plastic gears with them (the Autohelm syndrome :-), while the Simrad pilots have been top of the bunch ever since they had just a "Robertson" label.

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Old 10-02-2011, 15:50   #27
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I wish I could use a below decks unit. The competition has served well and there are a number of good solutions with modern interfacing.
Why can't you use a below decks unit?

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Old 10-02-2011, 16:02   #28
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Jedi-

I have a transom-hung rudder with a tiller in the cockpit; none of it is below decks so there is no place to attach it down below.

It is possible to buy a below-decks setup and either mount the linear drive in the cockpit (and arrange for my own waterproofing solution) or mount a linear drive in the lazarette and run the pushrod through the transom to a bell crank on the rudder (again a stout waterproofing solution is needed, this time at the hole in the transom). Carina has a very low freeboard, so the latter approach is particularly risky.

I was in touch a few years ago with a company that makes a drive that mounts remotely (below?) and drives through a flexible cable, but I needed a working autopilot quickly so I bought the X-5/GP from Raymarine which easily replaced the previous Raymarine 4000T/GP. I don't consider that a permanent fix however. Unfortunately Raymarine removed the clutch control from the X-5 so that won't work with the cable-driven drive.
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Old 10-02-2011, 16:12   #29
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I have a transom-hung rudder with a tiller in the cockpit; none of it is below decks so there is no place to attach it down below.
Ah, exactly what I was thinking. But... this is easy! Just put a hydraulic ram on the stern, lead the hoses up to just below deck level and lead through the stern using glands or even bulkhead connectors.

There you are; lots of outboard powered boats use the same system for primary steering.

ciao!
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Old 10-02-2011, 21:28   #30
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I assume you mean "proven price-performance" of the Ray pilots... I've had nothing but trouble and broken plastic gears with them (the Autohelm syndrome :-), while the Simrad pilots have been top of the bunch ever since they had just a "Robertson" label.
I have no experience of any of teh tiller pilots, but I can say that my Raymarine below decks units wehere very reliable and I delivered maybe 20,000 miles of these units with only one issue.

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