Many readers have commented on my Sailing with an Airmar PB200 entry. I enjoyed reading and responding to comments, and offer this diagram in response to some questions about mounting the PB200. The diagram above (click to enlarge) shows the parts unassembled, and then assembled on the masthead, along with an alternate "Plan B" my yard came up with before installation in the event my masthead was too crowded. (Credits to Jeff Willis at Willis Marine in Huntington, NY.)
The PB200 was designed to be used with marine VHF mounting hardware, like those I found at West Marine. On one end of the PB200 cable is a large two sided fitting that screws onto a standard VHF extension pole, after leading the cable thru the pole. With the fitting installed, the top of the pole then becomes a receptacle for the PB200 which is plugged in after all the other installation steps are completed.
Some things to look out for when choosing a location on your mast ... don't get too close to any masthead lights. My installation is very close to my tri-color and anchor light. As the lights are wider than the mounting pole, they are visible, but dimmer across a 10 degree arc where the pole is. It's fine, but had I used LED masthead lighting I would expect the light would have been entirely blocked across 10 degrees. I imagine this could be reduced close to zero if you can get the pole six or more inches away.
The instructions recommend a 3 foot distance from the VHF antenna (on your masthead). As my helm and nav stations is filled with electronics with such requirements that can't be meet, I have become numb to such requirements. Although I didn't have a problem, you could easily double the distance I got, by mounting as per Plan "B" in the diagram .. or attain the full 3 feet separation using a tall extension pole. Plan "B" also has the virtue of gaining additional distance from the masthead light.
The placement of the PB200 over the masthead, rather than forward or aft as you see with some top line wind sensors, provided astonishingly good results both upwind and downwind. I would highly recommend you do the same. The local birds might be unhappy, but the straight up and down installation is simple and sturdy.
I have had a Maretron WSO 100 installed on my Gozzard mast top exactly as you describe for 2 years now, with very satisfactory results.
The only difference is that I substituted a custom made base for the standard one as my mast top was not large enough to support the diameter of the standard unit.
Posted by: Bob at February 10, 2009 7:45 AM
Better mount without any significant light obstruction:
Lopolight (I know its pricey - but beautiful enough to make you want to climb the mast) has an optional top cover with incorporated 4" tall VHF mount. Aluminum and light weight.
Our mount: Lopolight topped by the optional VHF mount - 12inch Gemeco aluminum VHF mount extension tube (lighter and stiffer than Shakespeare extension) then wind sensor.
Note Airmar had a mock up - not produced yet - SB200 or something like that meaning sail boat with a mount on top for the VHF antenna.
VHF whip antenna is still an obstruction but can be at aft end of masthead or even extended a foot behind in a fairly typical install with Windex on the whip.
Note depending on your NMEA 2000 install having a compass at top of mast in addition to one in the hull produces a second string of conflicting compass information that can confuse some instruments/displays (Maretron) and not others (Simrad) - don't know about any other manufacturers.
Posted by: grandsoleil at February 10, 2009 10:04 AM
Which VHF mount did you use? The nylon one?
My mast is on the ground and I'm still doing a lot of prep work. For instance, I'm doing the drilling for a double spinnaker bail and I can do the drilling for VHF mount as well. The stainless steel version seemed pretty heavy, overkill.
Posted by: Olsonist at February 10, 2009 10:42 AM
The sailing version should have an LED tri-color and anchor light either built-in or have a mounting platform for them, instead of the GPS. It should also have an option to mount a VHF antenna on top. I think the recommended 3 foot separation assumes they are in the same horizontal plane; mounting the VHF on top should minimize interference. If the power and coax cables can't be designed to pass through, they could probably be designed to pass around in a loop at a reasonable distance so the interference with the wind sensor is minimized.
Norse, thanks for jogging my thinking a little. I actually can do this today. I have the Lopolight tri/anchor LED with the VHF lid, the last one sold. So I put the Shakespeare extender on top of the Lopolight, and I now can put the PB200 on top of that with no obstruction issues at all. The VHF antenna goes aft with the Davis windex rotating on it. I'll send some pictures next week when the installation is all done.
Posted by: Olsonist at February 10, 2009 6:17 PM
Norse: I think the GPS is used internally by the unit to calculate true wind and possibly refine other data so the instrument can send those PGNs without consulting other shipboard instruments. Since you can buy bluetooth GPS receivers for $30, I don't think it adds much to the cost of the unit!
I WORRY about heat and RFI from mast head lights affecting the unit; I'ld like to hear some comforting words.
And I would really like to know what Garmin's GMI-10 can do with all that data!
Olsonist wrote “Which VHF mount did you use? The nylon one?â€
--> I went with the stainless base and polycarbonate pole. I was concerned the nylon base was subject to damage by ice during winter storage with mast up. Remember to use corrosion protection if your masthead is a different metal, like aluminum.
Sandy wrote “I WORRY about heat and RFI from mast head lights affecting the unit; I'ld like to hear some comforting words.â€
--> I don’t see a problem, the PB200 is mounted 24 inches away
Wow this article captured the interest of many readers to respond … thank you all for being so engaging, this is a lot of fun for me.
I am writing this comment to clear up some confusion evident in comments regarding sensors involved in wind calculation.
For example there was confusion around true wind and which sensors were involved in calculating it that I want to dispel. For example the comments about GPS’s role in the calculation (GPS is not involved at all), some confusion about “what if’ VHF interferes with GPS would it interfere with true wind (no !), and does the GPS need to be in the PB200 to get these astonishing results (no !), or does the network move GPS information fast enough that the proximity of the GPS sensor matter.
So let me clear up the confusion about how true wind was calculated during testing. Hopefully I won’t cause any new confusion or make any mistakes doing this …
In the order I list below, is how I see the sensor information building upon each other to get the results I experienced.
Call me out if I screw up below, this true wind stuff gets tricky, but I am 97% sure this is how each of the sensors built upon each other:
1. PB200 Apparent Wind Speed and Angle = “on†and configured at 5x per second as an output to the NMEA-IN port of the Raymarine E-series. I believe the only sensors involved are the temperature and angle of heel corrected ultrasonic wind sensor, accelerometers, and motion compensation software.
Note: This was all that was used by the autopilot to steer 45 & 130 degrees off the wind, and obtain the astonishing wind readings I saw on my ST60 Wind Display, E-series chartplotter, and the amazing autopilot results I reported.
2. Next sensor up … isn’t on the PB200, but rather the paddlewheel sensor under the boat which is an input to the ST60 Tridata, which in turn outputs SOW (speed over water) onto the seatalk network to the e-series. This is needed for true wind calculation angle (as a number of degrees starboard or port from the bow) and true wind speed.
3. PB200 True Wind Speed and Angle (relative to the bow) = “off†(True Wind was instead calculated by e-series, using above sensors only).
Note: The True Wind readings that were appearing on my ST60 Wind Display, when I toggled true wind mode, used only the sensors above.
4. PB200 Compass Heading = “on†at 10x per second
Note: The E-Series then calculated the True Wind Speed and Angle (relative to magnetic north), and displayed on my e-series data window.
5. PB200 GPS Lat/Long + COG + SOG = “on†once every 2 seconds.
Note: The E-Series then calculated the Ground Wind Speed and Angle (relative to magnetic north) and displayed on my e-series data window. I have made no comments in the article about this reading, it wasn’t at all the focus of the testing, but mentioned here to highlight that the only role the GPS has in wind calculations was non existent until this step. It is an option of the PB200, in the event of a paddlewheel failure to substitute the GPS SOG for SOW, but that was not the case during testing.
I expect this explanation is going to support the point I made in an earlier comment that the compass heading and GPS sensors were not relevant to the results I experienced and the technological stars in this evaluation where the accelerometers, motion correction software, while the ultrasonic (no moving parts) wind measurements were important but secondary.
Make sense?
That’s not to say I don’t value the mast mounted PB200 compass. I did get great results and agree with Ben, that "our notion of where to put a compass may get inverted". When I get back in the water I expect I will find this will greatly improve the true wind angle (relative to magnetic north) and ground wind angle and speed reported ... measurements that in the past were so inaccurate I really didn’t give them much attention. I also expect I will find my e-series displaying better set and drift information, that can be useful in navigating the shortest distance on my longer passages.
Again, thank you all for being so engaging, this looks like one of the most commented on articles on Panbo, and it has been a lot of fun for me.
Dan
My aging ST50 instruments are sitting in a grocery bag covered with fiberglass dust, and I'm very interested in the Airmar PB200. I am very glad you've shared your positive experience with it. Where you have chosen to do true wind calculations in your tridata to send to your chartplotter, I would prefer to use all of the features of the PB200, in which case the GPS, compass, accelerometers, and motion compensation software are used by the internal processor to send true and apparent wind data as distinct PGNs or NMEA words without needing external data from the paddlewheel. This frees up the processor in the chart plotter.
The difference between using speed through the water or speed over the bottom was debated elsewhere recently and got bogged down in syntax. My simple mind is only capable of distinguishing true wind as what you feel on your face when you aren't moving, versus what you feel on the boat. The difference is the movement of the boat, which is the sum of current, crab, and progress through the water. Crab is very important to a catamaran with shoal draft keels. And its very difficult to measure.
I may have missed the answers, but I'm still wondering. Would the EMI from a Masthead LED affect the PB200? Will the compass in the PB200 provide the data rate needed for MARPA? Can a nearby VHF antenna be a problem? Do I have enough room left in the electrical conduit in my mast for yet another cable and plug? Who is going to win the Belmont?
Sandy wrote "I am very glad you've shared your positive experience with it."
>> Your welcome!
Sandy wrote "Where you have chosen to do true wind calculations in your tridata to send to your chartplotter"
>> The tridata provides a SOW source to the e-series chartplotter, the charplotter does the true wind calculation.
Sandy asked "Would the EMI from a Masthead LED affect the PB200?"
> Don't know. Not apparent to me why there would be a concern.
Sandy asked "Will the compass in the PB200 provide the data rate needed for MARPA?"
> Yes, meets the 10hz data rate that most people use, and worked well with MARPA on e-series.
Sandy asked "Can a nearby VHF antenna be a problem?"
> Don't know. Not apparent to me why there would be a concern. Should it be, disable the compass and GPS, the other sensors are what give the astonishing wind results, the compass and GPS already exist on most our boats already.
Sandy asked "Do I have enough room left in the electrical conduit in my mast for yet another cable and plug?"
> How to tell ? The way my yard passes the cable thru the deck, to minimize the size of the penetration, the plug needed to come off anyhow and be spliced back on. I used the fat cable that supports NMEA-0183 and NMEA-2000 simultaneously. If I was just using NMEA-2000, I would have run the thin NMEA-2000 cable up the mast and made the connection at either the masthead or the mid-mast radar mount instead.
I (Dan) wrote "I used the fat cable that supports NMEA-0183 and NMEA-2000 simultaneously"
>> BTW: I didn't do this for redundancy, rather I was also evaluting the WeatherCaster PC software which hasn't yet been released for N2K. That I can evaluate next on N2K with the same cable is very cool.
Thanks Dan.
The EMI concerns originated from some reports of interference from LEDs at SSCA.
All lights generate some heat which would affect the tiny variations in wind velocity between the ultrasonics. I'm sure that this effect was considered, and some precautions were developed, but I have a very busy masthead; it ain't pretty up there.
Thanks, Dan, for all the info on the PB200. I've been anxiously awaiting its availability since replacing my other (dead) sailing instruments with N2K models last spring.
I suppose the coments concerning RFI, data rates, mounting options, and the subtleties of 3-axis accelerometer corrections are appropriate for a propeller-head forum like Panbo (sorry, Ben). But what I'd REALLY like to hear is more information on its performance while sailing to help tease out puffs and wind shifts. (I mean, BOATING is the ultimate objective, after all.)
Dan, your description of the PB200's excellent performance in autopilot-assisted sailing was very useful. From the description, I imagined that your "steady winds" were somewhat over 10 knots upwind. Have you been able to suss out its performance in lighter air yet? In particular, the PB specs suggest less accuracy in winds under 10 knots. Does this manifest itself when the wind drops, e.g. resulting in increased variability of readings that are not damped out?
Perhaps when you get some round the buoys experience this spring you can provide us with a "Sailing with an Airmar--Part III"!
Posted by: JCS at February 25, 2009 2:13 AM
JCS - Yes, all the on the water tests were above 10 knots true, with apparent wind higher or lower depending on my course. The lowest apparent wind my autopilot was steering in was 6 knots.
I look forward to reporting more on the water experiences in Spring.
JCS askes “Have you been able to suss out its performance in lighter air yet?â€
-->With the autopilot no, but at the dock I gained some clues. At the lowest speed I observed (around 2-3 knots) at the dock the PB200 gave me a wind angle I could still believe in (keep in mind I had no way to judge wind accuracy better than say +/- 20 degrees). Both appeared to do fine as long as my boat held steady, when the mast sways or the wind changes direction … no matter the wind speed, a performance difference in reporting wind angle opens up. The PB200 steadfastly held to the reported wind direction even as the mast swayed from the small wakes of passing boats in the nearby 5mph zone, where the mechanical vane and ST60 combination errantly reported a wind angle change.
JCS wrote “In particular, the PB specs suggest less accuracy in winds under 10 knots. Does this manifest itself when the wind drops, e.g. resulting in increased variability of readings that are not damped out?â€
-- > It came as a surprise to me, when testing at the dock that I would see a difference between the mechanical vane and PB200 … as I am in a 5 mph no wake zone, and thought the ST60 damping function would be entirely effective. I even dragged 100’s of feet of old line from home in preparation for testing ... to induce a bigger mast movement, but it turned out unnecessary.
It didn't take much mast shake to see that the wind angle readings were effecting the mechanical vane and not the PB200.
As a result of this surprise, I spent multiple visits at the dock attempting to find a better damping value for my ST60 / wind vane combination to see maybe if I could close the performance gap with the PB200 when the mast is swaying, and in doing so tried different values for the ST60 connected to my PB200 as well.
I became comfortable with the ST60 connected to the PB200 being set at the lowest damping setting, I continued to see a smooth tracking between the observed movement of the wind vanes and the ST60 display, and got quicker response times as a benefit of the low damping value. I have not tried this low damping value on the water … I’ll do that in the Spring, but in any event the autopilot wouldn’t be effected … it gets the un dampened wind direction right from the PB200 across the seatalk network. I later learned the PB200 WeatherCaster PC software has a damping configuration setting also … I did not experiment with it.
I also came to believe the damping setting Raymarine uses as default for the mechanical sensor is correct. It just doesn’t dampen out as much as I had believed all these years. I am guessing the rather low period of the mast swing limits how much damping can be applied before users become fustrated with the readings being delayed.
Thanks again, Dan, for sharing your experience. It's been my experience, too, with mechanical sensors in light air that lateral motions at the masthead introduce transitory variations in wind angle readings that one eventually learns to discount. It requires patience and experience (not to mention reliable short term memory) to discern a subtle but persistent wind shift. (Which ability, as they say, is worth thousands of dollars in go-fast sails!)
It certainly seems to me that sophisticated error-correcting algorithms as exemplified in the PB200 have the potential of dramatically improving wind instrumentation for sailors. And with Ben's report of a forthcoming 3-axis rate gyro in the PB series, Airmar is evidently not resting on it laurels!
Posted by: JCS at February 27, 2009 3:46 PM
My tax refund just covers a PB200. Providence has spoken.
Could we ask Dan for any new information he has regarding the PB200?
Posted by: Bill at July 18, 2009 6:07 AM
The PB200 is easily my most favorite addition to the marine electronics on Breeze Pleeze, and won't need much prompting to write more about it.
I am unsure if Part III will be about converting over to NMEA-2000 (see post today about the new network on Breeze Pleeze), more experience on the water, or a visit planned by Airmar to come aboard Breeze Pleeze on a day with especially turbulent weather and seas with some fancy equipment to help measure and report on performance in some depth.
Leave a comment