Any disadvantages to ultrasonic wind sensor?

[Dockhead]

I'm just back from my first cruise and first practical experience with the WSO ultrasonic wind instrument.

So far my experience is exactly like others'. It works perfectly.

I ended up having a long aluminum pole made for it, about 1.2 meters long. It goes straight up from the masthead without any bends or kinks. I figured that 1.2 meters would be enough to get it out of any turbulence, and that a straight pipe would be better structurally. Aluminum so it wouldn't be too heavy and shake itself loose (the stainless pipe I bought was horrendously heavy).


I am using the B&G Triton displays for it, which are the best wind displays I have ever seen, by far. The analogue representation of True and Apparent at the same time is absolutely brilliant. The only flaw for me is that the numbers for the digital display are slightly too small for me to see easily from the helm (the displays are mounted on my scuttle about 3 or 4 meters forward of the helm).

While we're talking about ultrasonic transducers, I also have an ultrasonic speed transducer. I am less convinced of its accuracy, than of the accuracy of the Maretron WSO100 wind transducer. My speed transducer is an Airmar CS4500, installed at horrible expensive and considerable trouble. The transducer itself is expensive, and then -- it doesn't output N2K, it doesn't even output NMEA0183, it only outputs pulse. So I had to buy a pulse-to-NMEA0183 adapter (Actisense), then wire NMEA0183 to my Zeus plotter, which bridges that data to N2K.

If I were you (speaking to the OP), I would consider the LJ Capteurs transducer. I haven't seen any actual practical reports on it, but right off the bat you have advantages in that it was designed specifically as a sailing instrument. Besides that, it is much smaller. I would bet that it is better than the WSO100. Do they make it in an N2K version yet? If not, that would be a downside. I didn't buy one because at the time I was buying my gear, there was no N2K version, although it was promised for the nearest future.

Yesterday when motoring in a glassy calm, I cranked up the engine to blow the cobwebs out, as I regularly do after motoring at low speeds for long periods of time. As I passed 10 knots of boat speed, the speed transducer went crazy, eventually giving me a reading of 35 knots. I am guessing that if I exceed hull speed some air gets entrained under the hull, and this throws off the transducer. If that's what's happening, this will be serious disadvantage when sailing downwind at high speed, where you really, really need to know your speed in order to stay out of trouble. This is all pretty disappointing after spending more than $1000 on this setup.

[China Doll]

Thanks for the reply. I was noticing on the 'sale' websites info concerning the humidity bulbs in that it seems these need replacing every so often:

"They include additional sensors such as a 10Hz GPS, solid-state compass, tilt sensors and a field replaceable relative humidity sensor"

And also:

...

• Optional field-serviceable relative humidity sensor

Benefits of the WX Series Include:

• Removable humidity sensor that is field serviceable
• IPX6 waterproof rating (units with the relative humidity module are IPX4 waterproof rated)...

This last bullet point doesn't bode well for durability or lifetime serviceability as if you get the optional RH module, you lose some of the protection against moisture intrusion.


-Rob.

[goboatingnow]

IPx4, on the top of teh mast, forgeeetit.

dave

[Dockhead]

Originally Posted by goboatingnow

IPx4, on the top of teh mast, forgeeetit.

dave

Indeed. I'm surprised. That's actually quite bizarre.

The Maretron WSO100 is IP67. http://www.maretron.com/products/pdf...0Datasheet.pdf

Defined as totally dustproof, and waterproof at least to immersion for 30 minutes at 1 meter depth. IP Code - Wikipedia, the free encyclopedia

IPx4 means not dustproof at all; somewhat splash resistant. WTF?

[s/v Jedi]

What are "humidity bulbs"?