Fitting Nasa wind mast unit

[paulwornell]

I have aquired a secondhand NASA wind system. The mast head unit has come with 2 pairs of black plastic blocks that presumably screw to the mast and clamp the round metal shaft of the unit. However, I can't work out what will stop the shaft rotating when fitted via the plastic blocks. Advice and guidance would be welcomed.

 

[Trundlebug]

Friction.

If the plastic blocks are tightened enough, the mast head unit shaft won't rotate. Or at least, mine hasn't in 5 years.

 

[VicS]

Instruction manual at http://www.nasamarine.com/pdfs/Clipper wind.pdf

 

[Retired in Crete]

I have just bought a new one. Two of the blocks (out of four) have a strip of foam rubber in them which is compressed when the shaft is fixed.

Hope this helps

John

 

[Caer Urfa]

Friction.

If the plastic blocks are tightened enough, the mast head unit shaft won't rotate. Or at least, mine hasn't in 5 years.

+ 1, fitted mine 6 years ago and still going ok.

However after speaking to 3 of the major wind indicator manufacturers they all said more or less that if I fit it on my pushpit mast which is 9' above sea level and 8 ' from the back of my boom I 'could' expect a differance of 'up to' 1,5 knots max in wind speed readings depending on the direction of the wind flow over the main sail, time has shown and with checks by a hand help meter the max differance has been 'occasionally' 1 knot max.

As I have a motor Sailer I am more interested in where the winds coming from and roughly indication of the wind speed, plus any problems I can have it off the mast in 10 minutes and not having to mast climb !!

Mike

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