Reckless Behavior of CF Member !

[Blue Stocking]

James,

I will ask my mates up at Harbour Radio to let me know if he passes through Bermuda's IMO avoidance zone, and will give you a head up.

Time to mount the bowchaser on the barge.

[deckofficer]

Originally Posted by bobconnie

Gee you guys mean theres stuff like this out there?? really? I mean I love a auto steer, and love most any type of wind vane ! but steering under sail automaticly !! boy Im really behind !! I have a old hand held Gps I better start readin a little! LOL Im not really kidding at all LOL Im way behind !! Bob and Connie

Being behind the curve isn't a bad thing, it keeps your celestial nav skills fresh. Perfect pin wheel anyone?

[Cheechako]

thanks for the warning. A buddy of mine integrated his gps and autopilot. Shortly thereafter, he T-boned a large steel midchannel bouy dead center! The bouy was his mark, and he set it and got busy doing things..... costly! He knew the bouy was up there and had chekedc on it a couple times, then got distracted...

[Sailagain]

Originally Posted by Cheechako

thanks for the warning. A buddy of mine integrated his gps and autopilot. Shortly thereafter, he T-boned a large steel midchannel bouy dead center! The bouy was his mark, and he set it and got busy doing things..... costly! He knew the bouy was up there and had chekedc on it a couple times, then got distracted...

That's one of the first things my instructor said about GPS and setting track lines (that could be used with autopilot). Always go to the side of the buoy. Also when setting way point marks - be ultra careful you aren't zoomed out too far - because you could place the way point on a wreck, rocks or other marker - then your way point marker will cover over whatever is under it.

[sailorboy1]

Originally Posted by Cheechako

thanks for the warning. A buddy of mine integrated his gps and autopilot. Shortly thereafter, he T-boned a large steel midchannel bouy dead center! The bouy was his mark, and he set it and got busy doing things..... costly! He knew the bouy was up there and had chekedc on it a couple times, then got distracted...

I saw a power boater do that in Boston a couple of years ago, made a big hole!

That is one of the reasons I have an alarm programmed into my system to alarm prior to getting the waypoint; so I know it is coming up!

[s/v Jedi]

Complacency !!

p.s. check the name of this boat

cheers,
Nick.

[Bash]

Originally Posted by CarinaPDX

Well I have had multiple (i.e. at least 4) Raymarine autopilots, the current one being an SPX. I know what Raymarine has in the literature, but I also know how they work. Because masthead wind indicators are so unstable they have to average the results over a pretty significant amount of time. Thus they cannot respond quickly to changes in wind direction. We had a saying in the high tech industry: if you can't fix it, feature it. So they are saying that by ignoring short term changes in wind direction they can steer a straight line - making my point nicely. As for experience, when on the wind I have had to sail a bit lower and overtrim more than I would by hand or vane in order to prevent the sails flogging on small changes in wind. It works; just not nearly as well as a vane.

Sounds as if you need to tweak the rudder gain and response levels. You can get an autohelm to respond to minor changes in wind direction if that's what you want. For my part, I don't think that an overactive helm is a good thing.

[44'cruisingcat]

Originally Posted by Bash

Sounds as if you need to tweak the rudder gain and response levels. You can get an autohelm to respond to minor changes in wind direction if that's what you want. For my part, I don't think that an overactive helm is a good thing.

Or less damping on the wind indicator.

[s/v Jedi]

Originally Posted by Bash

Sounds as if you need to tweak the rudder gain and response levels. You can get an autohelm to respond to minor changes in wind direction if that's what you want. For my part, I don't think that an overactive helm is a good thing.

If you have an old-tech wind-sensor which is coupled to an instrument that dampens the data to something like a 1 minute rolling average and the instrument connects to NMEA, then the NMEA data will be that 1 minute average. However, you often can change those dampening settings, which would make it all a bit more responsive. That is... assuming that the data output frequency is high enough.

I think it will only start working good if the autopilot gets raw undampened data and knows how to handle that.

EDIT: cruisingcat.. a bit longer and you can take over from me

ciao!
Nick.

[deckofficer]

No replies to my question "Perfect pin wheel anyone?" Does that mean what I think it means? If so, I will start a poll on that subject.

[s/v Jedi]

Originally Posted by deckofficer

No replies to my question "Perfect pin wheel anyone?" Does that mean what I think it means? If so, I will start a poll on that subject.

ciao!
Nick.

[CarinaPDX]

Actually, I got rid of the wind sensor years ago - it just didn't do well enough to justify its place on the boat. Watching the small wind sensor twitching around made it clear that the fundamental input was too unstable to detect shifts quickly; high sample rates don't change that. And on the masthead the change to AWA with pitching and rolling again makes instantaneous measurements problematic, particularly on a monohull. I know that at least as recently as the 4000+ model that I had that the system responded as described before (steer to compass, modify heading with change to average AWA, slow response) because that is what a Raymarine engineer told me when I talked with him at the Southampton boat show. The problem is the limitation of unstable input from a wind feather, potentially at the masthead, that couldn't provide stable information quickly, and not an issue with sample rate or damping/response of the autopilot.

That said, I have heard good things about the Navico (Simrad etc) autopilots, and with their modern sensors they should do better than Raymarine with their primitive mechanically-gimballed flux gate compasses and wind-feather AWA sensor. And more sophisticated signal processing should improve results. So I will happily revisit this once the most recent Raymarine dies, as they always do. (I already have the Maretron SSC200 in my system - and 3 Raymarine compasses collecting dust - and will be adding the Maretron weather system in a year or two.)

I think this gets blown out of proportion (not to mention thread drift). I have used both APs and vanes to steer for thousands of miles under sail, and both do work. In some conditions (e.g. downwind in light air) the AP outperforms the vane. In others (e.g. hard on the wind) the vane does noticeably better. Mostly there is overlap between the two technologies; but only the AP will steer under power and only the vane will steer without (electrical) power. For me, both are essential on an ocean-crossing monohull. But catamarans are a bit different (duh!): they are a much more stable platform for the wind sensor, and rarely would a well-helmed cat be hard on the wind so that advantage of a wind vane is not particularly relevant. Horses for courses...

[deckofficer]

The new and improved poll for celestial navigation.
http://www.cruisersforum.com/forums/...oll-76732.html

[s/v Jedi]

The Maretron SSC200 is great; I have the same and also Mark, who reports that it works 100% with the Simrad autopilot. He still needs to calibrate it, as it is now showing an error of 10 degrees or so, but he is just steering to waypoints with the integrated system, being lured by the Sirens and all that, so he will do the turns when he finds nice flat water with some room

ciao!
Nick.

[goboatingnow]

But I still much prefer the romance(?!) of the approach from Shane Acton ("Shrimpy" - 18' Plywood Caprice - RTW in the 1970's)...."sailed into the Atlantic for a few days, and then turned left" (I paraphrase)......he was heading from Europe to the Carribean - made landfall in Brazil ........even if he probably made up that quote (passage plan?!) only when he wrote his book.....

Sorry he's crossing east to west and he turned left. You sure he didn't mistake Africa for Brazil, maybe he actually got to Dakar.

As Paddington Bear said, I know my left hand is opposite to my right , but its where you start that confuses me.

dave