Actually "Apart from the fact that conditions are calm, I dont see that pitching etc would effect the accuracy of windspeed, though they could direction, as the sensor is moving in a circle."
Though I already responded to this when you first posted it - I will say this: You mean to tell me that movement of the wind speed meter doesn't affect its reading?
To amplify, any effect due to gravity or impetus would be offset as in a circular motion one side and the cups offsets the other. I thought you got it.
What are you even trying to say here? That the fact that the cups are moving in a circular motion means that movement on the top of the mast doesn't affect the values reported? Because if that is what you are saying - you are nuts.
Think about it. Lets say there is 5kts of apparent wind at the mast top. Lets say the boat pitches forward. The mast top is now accelerating so the apparent wind is lower then 5kts (and circular motion doesn't matter as apparent wind hasn't changed directions yet). Once apparent wind goes to zero at the mast top (assuming it has pitched far enough, fast enough) there will be a "negative" wind speed registered due to the circular motion. Of course there is no "negative" wind speed but it is in the opposite direction. When the boat pitches back, it must go though that whole process in reverse. The "negative" wind speed must decrease and go to zero while the "positive" wind speed must increase back to 5kts.
During that entire time the values are inaccurate and less then 5kts. Do _YOU_ get it now?
The fish is to reflect that anecdotal evidence, particularly when a fairly loose account which doesn't hold up very well to closer examination is of dubious value. One might apply scepticism to fisherman's accounts, and sailors' accounts of wave heights, wind speeds and boat speeds regardless of their general honesty.
You mean like your accounts of anemometer accuracy? Something claimed and never shown?
The claim that apparent zero wind at deck or boom height evidenced by telltales and masthead annenometer's zero reading, means that boat speed on the log equates with windspeed on the boom and the mast top, other than momentarily, in the absence of current, and significant measurement error other than unreliability of readings under 1 knot, in my view falls into that category of warranting scepticism.
I really couldn't care less about your scepticism. The only real thing you seem to have an issue with in all of this is the accuracy of an anemometer and I have posted a website with product specifications identifying the speeds _you_ calculated for the mast top to be within the range of low speed error.
Compound that with the valid argument that pitching affects the anemometer and the values are to be expected.
You have said nothing that would invalidate either of these things. Other then your own fish story.
I honestly never expected I would get so much crap by trying to explain something that someone saw.