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Old 28-10-2011, 07:06   #31
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Re: Why Integrate the Autopilot ?

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Originally Posted by Dockhead View Post
This does not apply on a reach, especially a broad reach, where a few degrees of wind shift will not require a course change to maintain sail trim.
Actually, sailing downwind to a wind angle can be more safe on passages - particularly at night - where an unnoticed windshift and unintended crash jibe can do damage. Letting the boat follow the wind around allows you to time to take notice of the changing conditions and calmly prepare the boat for a jibe before execution.

Jimmy Cornell recommends that all autopilots be put on steer to wind function during night passages for this reason.

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Old 28-10-2011, 08:12   #32
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Re: Why Integrate the Autopilot ?

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Originally Posted by colemj View Post
Actually, sailing downwind to a wind angle can be more safe on passages - particularly at night - where an unnoticed windshift and unintended crash jibe can do damage. Letting the boat follow the wind around allows you to time to take notice of the changing conditions and calmly prepare the boat for a jibe before execution.

Jimmy Cornell recommends that all autopilots be put on steer to wind function during night passages for this reason.

Mark
I agree. I will not use the pilot without wind following mode, anywhere near a run (and the preventer goes on whenever the mainsheet is not tight).

Wind following mode is fantastic -- my usual autopilot mode when sailing. It works extremely well on my boat despite the fact that the electronics are all 10 years old. Kudos to Raymarine.
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Old 28-10-2011, 08:57   #33
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Re: Why Integrate the Autopilot ?

My sailboat has an integrated system but the boat I've done two passages on in the last year does not. While on these two trips we've had to hand steer the boat. The first time was across the Gulf from Key West to Galveston. It was an incredibly hard 6 days and required two people on watch at all times. Needless to say we were exhausted and due to that the potential for error was greatly increased. The most recent trip was just an overnighter but it still was very tiring.
My boat ( a 44 footer) can be single handed. I've even added the remote control to the autopilot so the boat can be steered from anywhere on deck. I use the track mode and set a new way point upon reaching the set point. ALL kinds of alarms go off as I near my way point. This allows for only one crew member on watch.
On both boats there's a chartplotter and I always have a lap top with navigational software as well as paper charts as back up. On passages it really simplifies the navigational process by setting a way point and steering towards it. Honestly, having the autopilot do it is a lot less wear on the crew. It allows for more people to rest and allows the person on watch to be more rested. I think the lessens the potential for mistakes.
There are a lot of people that are of the mind set that their autopilot lessens their responsibility for good seamanship. I think that's just an accident waiting to happen. But then again, those same people will let ropes trail in the water, carry on conversations on channel 16 and all manner of other things that good sailors find annoying and stupid. Electronics are great tools and just like all kinds of other great tools they are only as good as the person operating them....
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Old 28-10-2011, 09:16   #34
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Re: Why Integrate the Autopilot ?

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Originally Posted by Dockhead View Post
. That's called "sailing".

sailing is adjusting your trim to go where you want to

if in Track mode the boat is adjusting heading to stay on rhumb line it is doing the same thing you would do if hand steering, it's just doing it better
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Old 28-10-2011, 09:23   #35
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Re: Why Integrate the Autopilot ?

If I'm at the nav station and decide to adjust my course five degrees to port, I can do that from the chartplotter rather than having to trudge all the way back to the binnacle where the autopilot head is mounted.

A nice feature when it's raining.
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Old 28-10-2011, 09:54   #36
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Re: Why Integrate the Autopilot ?

G'Day Greg,

One thing to note: it isn't necessary to have an "all-in-one" instrument to have your autopilot linked to wind or GPS -- a feature we also use. Stand alone instruments can also be thus linked.

I share your distrust of having all your instrument eggs in one basket, and further, I've noted that such conglomerations draw quite a lot of power compared to individual sailing instruments. So, as far as we've gone with instrumentation, stand alone has won out.

Cheers,

Jim
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Old 28-10-2011, 12:47   #37
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Re: Why Integrate the Autopilot ?

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I use the wind angle steering feature a lot when close to the wind and when reaching in light air--I find that following the wind shifts and puffs adds about half a knot to my average boatspeed under autopilot.

I have not interfaced the autopilotpilot to follow waypoints. When I am sailing on a compass heading, I use the GPS Course Over Ground and Bearing to Waypoint readouts to adjust the autopilot heading. Part of being on watch is to keep track of the COG and BTW and adjusting course if necessary.

I also believe that following waypoints in congested areas is a good way to generate collisions or close calls. My course adjustments are not as efficient or accurate as the automatic waypoint following systems, so there is more crosstrack error in my course. If you have a cross track error of 0.01 miles or less, that means you will come within 50 feet of everyone else who has a cross track error of 0.01 miles and is traveling between the same waypoints.

Bazzer, you must have been motoring, not sailing, if you could let the autopilot follow waypoints from Benecia to the Golden Gate. That course involves several tacks in the prevailing winds, and I would have been using the wind angle feature most of the way.
Actually you are right, well all of the above. This particular trip involved motoring, sailing and some drifting. It was a three days with two nights at Angel Island. I would not want to be without the so called integrated Raymarine system for this or any costal sailing, it takes all the worry and stress out of it, particularly when single handed. The AP does have a problem keeping on course below 2 knots, but then I really should put the motor on. ( I hate motoring) This was particularly true coming back through the Gate on the end of a ebb tide and some very sloppy conditions. With the traffic and tides etc there is a need to keep a eye on the COG and to make a few degrees correction every now and then, easy to do with the AP controller, in my case a ST7001. I don't sail to the wind with the system as being a long time dinghy racer I prefer to sail upwind by the seat of my pants. Reaching and running just keep on course and trim the sails to suit.
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Old 28-10-2011, 13:55   #38
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Re: Why Integrate the Autopilot ?

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I would not agree with this. In its basic mode, your autopilot will maintain a constant heading. Its mission in life is to steer the boat so that the bow is pointed in the same compass direction all the time. This is a good and useful mode, and you can sail in this mode in most conditions without any big risks. If the wind shifts, your sail trim will require correction. If there is a big wind shift, you could have an accidential jibe or other problems, but unless you're sailing quite close to a dead run, this is usually not a big risk.

Track mode lets the pilot steer the boat however it likes -- and on different headings -- in order to get onto the rhumb line and stay there. If you get swept off the rhumb line by a current, then the pilot will turn the boat and steer you in what might be an altogether different direction, in order to get you back on the rhumb line. Then it will turn back towards your waypoint and fiddle until COG and bearing to waypoint are the same. I have seen course changes of 30 and 40 degrees in track mode, as a result of this. In my opinion, this mode is entirely inappropriate for sailing, for that reasons.

You might not notice it if you are not sailing with big tidal currents (like where I sail), but if you are not sailing with big tidal currents, then you don't really need track mode anyway. You can use the basic heading mode, and adjust the given heading until COG equals bearing to waypoint, and you're set. Leeway is compensated. If leeway changes or the wind shifts, you will have to make adjustments. That's called "sailing".
The point is, you have to watch what's going on in either mode. In track mode the sails may need re-trimming, in heading mode currents may push you so far off course as to be sailing towards a reef or island, so the heading may need altering.

As you say, it's called sailing.

Changing the heading until COG and Bearing match is simply doing manually what the pilot would do automatically in track mode.
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Old 28-10-2011, 15:01   #39
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Ah ha, my boat will not crash gybe since I have a Dutchman Boom Brake installed and it works great. But even at night I keep a watch at all times as everyone should.
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Old 28-10-2011, 15:22   #40
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Re: Why Integrate the Autopilot ?

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Why are some of you assuming because the autopilot is getting course instructions from the GPS that no one is watching and able to respond or tweak the pilot?
For the same reason that the effect of airbags in cars is not to save lives so much as it allows careless speeders to survive their crashes.

I read a book recently where "family movie night" on an autopiloted cat took precedence to actually knowing where the boat was. A reef wreck and a severed leg later, I wasn't convinced the voyagers in question had learned the right lessons about keeping a proper watch.

As for the subject of integration, I feel combining the GPS and the autopilot should be used sparingly, if at all. Sailing to a course just via a preset compass point...and then failing to arrive where you think you should be at a waypoint... helps to reveal errors in sail trim, set and drift of tide, unexpected currents, and so on.

I also support the idea of having a wind vane for sailing (improves trim and uses no amps) and an autopilot for motoring or motor sailing.

My own nav resources are shaping up to be standalone RADAR and AIS, which feed into PC-based chartplotting, a standalone GPS at the helm to calculate SOG/COG, XTE, etc. the usual fluxgate and magnetic compass, and an AP for the hydraulic steering stations and a wind vane for when those stations are bypassed in favour of a tiller. Experiences delivering other boats has convinced me that you want two self-steering options BEFORE you have to hand-steer...unless you are well inshore.

Integration can be helpful in limited or selected situations, but I could lose the plotter first and keep the rest quite happily, as I plot on paper for the most part.
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Old 28-10-2011, 15:25   #41
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Re: Why Integrate the Autopilot ?

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Originally Posted by colemj View Post

Jimmy Cornell recommends that all autopilots be put on steer to wind function during night passages for this reason.

Mark
A prudent idea, I think, along with "steer to wind under reefed down sail". The potential for drama does increase at night. For the same reason, it's handy in certain conditions to tune the RADAR for rain bands and to set up a guard ring to give you a bit of warning of squall activity.

Basically, I'd rather make 50 NM overnight in the right direction under good control than "best possible speed". Most sailing couples do not have the strength alone to trim the boat to best speed in evolving conditions, so sacrificing a bit for a calmer overnight is worth it.
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Old 28-10-2011, 15:26   #42
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Re: Why Integrate the Autopilot ?

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For the same reason that the effect of airbags in cars is not to save lives so much as it allows careless speeders to survive their crashes.

.

I just don't follow the reasoning here to autopilots!
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Old 28-10-2011, 15:32   #43
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Re: Why Integrate the Autopilot ?

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For the same reason that the effect of airbags in cars is not to save lives so much as it allows careless speeders to survive their crashes.

I read a book recently where "family movie night" on an autopiloted cat took precedence to actually knowing where the boat was. A reef wreck and a severed leg later, I wasn't convinced the voyagers in question had learned the right lessons about keeping a proper watch.

As for the subject of integration, I feel combining the GPS and the autopilot should be used sparingly, if at all. Sailing to a course just via a preset compass point...and then failing to arrive where you think you should be at a waypoint... helps to reveal errors in sail trim, set and drift of tide, unexpected currents, and so on.

I also support the idea of having a wind vane for sailing (improves trim and uses no amps) and an autopilot for motoring or motor sailing.

My own nav resources are shaping up to be standalone RADAR and AIS, which feed into PC-based chartplotting, a standalone GPS at the helm to calculate SOG/COG, XTE, etc. the usual fluxgate and magnetic compass, and an AP for the hydraulic steering stations and a wind vane for when those stations are bypassed in favour of a tiller. Experiences delivering other boats has convinced me that you want two self-steering options BEFORE you have to hand-steer...unless you are well inshore.

Integration can be helpful in limited or selected situations, but I could lose the plotter first and keep the rest quite happily, as I plot on paper for the most part.
I fully agree with all of the above.
Who knows how to navigate without electrics? My Davis plastic sextant usually puts me within a few miles of where I expect to be. Anyone read the account by the so called skipper of the s/v Quantum Leap that was abandoned because of failing electrics and a injury which sounds like it could have been easily avoided. Anyone want to go find the boat?
What it all means is that you should know how to sail without all the modern aids....
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Old 28-10-2011, 15:56   #44
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Re: Why Integrate the Autopilot ?

I still don't understand the connection between integrated instruments and keeping watch. Lots of arguments against integration are presented here that conflates the two.

They have nothing to do with each other.

Interestingly, the wreck you use as an example might not have happened if the autopilot was steering to a course instead a heading.

And some of us can recognize poorly trimmed sails, the presence of currents and the set and drift of tidal flows without failing to arrive at our destination. This is actually a good example of seamanship, as compared to whether your instruments are integrated or not.

Not all boats can carry or use windvanes and I don't see any functional difference between a windvane and an autopilot integrated with the wind instruments. They both steer to wind.

Except, of course, that the use of an autopilot forces people to leave the watch and do stupid things, while using a windvane gives one virtue and constant vigilance...

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Old 28-10-2011, 21:40   #45
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Re: Why Integrate the Autopilot ?

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I just don't follow the reasoning here to autopilots!
Perhaps my review of the book "Black Wave" will illustrate my problems.

The sea is a dynamic place. A little bit of help on the helm is welcome, certainly, but that should only free up the prudent skipper to keep a better watch for other ships, course deviations, sleepy whales and awash containers.

I have yet to see an awash container. Everything else, I've seen.

APs slaved to GPSes are great only if the skipper has confidence that there are no, and I mean no, obstacles or dangers between the setting of the waypoint and the arrival at same.

That sort of confidence might be logical in familiar waters, still, logs appear, and I've noticed, after a flooding rain on a nearby river, an awash picnic table alongside that would've likely cracked my stem had I sailed into it at six knots. So keeping a watch is critical. It needn't be onerous, but it's critical.

The AP relieves the helm, and throwing in the GPS means errors in helming or set, drift or some degree of wind shift will be compensated for and the heading will be maintained until the WP is achieved.

Pardon me for suspecting, as a student of human nature, that this might breed a certain complacency in the sun-dappled skipper on passage.

Better I (personally) have to fiddle, tweak, replot and recalculate in a sort of hands on, pushing the +1 degree button on occasion, squinting at the sea sort of way, rather than to assume there is no impediment to my AP following my GPS's course like a good little robot...that doesn't give a damn about being drowned.
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