Rotavecta vs Vane

[wooslehunter]

I'm looking to replace my old instruments. I'm looking at the Raymarine ST-40 range which is supplied with a Rotavecta wind guage. I've heard that the rotavector isn't as good as the ST-60 vane system. BUT, it's a load cheaper.

So anyone have any comments on what the two systems are really like? i.e if the rotavector is accurate to +/-1 degree & the vane is accurate to +/- 0.1 degree, then who cares.

 

[SteveA]

I've had the ST40 with Rotovecta for a year and wouldn't recommend it - wind speed seems OK but direction! it has a mind of it's own. I've followed the calibration sequence so many times I should be dizzy and been in contact with Raymarine about it but it still shows any direction it wants.
Given the choice I'd go for one that has a vane.

 

[jerryat]

[ QUOTE ]
I've had the ST40 with Rotovecta for a year and wouldn't recommend it - wind speed seems OK but direction! it has a mind of it's own. I've followed the calibration sequence so many times I should be dizzy and been in contact with Raymarine about it but it still shows any direction it wants.
Given the choice I'd go for one that has a vane.

[/ QUOTE ]

Entirely agree. Friend of mine had the Rotavecta from new and was very disappointed with the 'direction' which, from my own observation, was a joke. He stuck it for abouot three years then swallowed hard and ditched it in favour of a vane system.

So I'd definitely go for the vane - far more stable!

 

[paulbowen8]

I have the same problem with mine. It reads OK for a while then spins around wherever it wants. Not good for wind vane mode on the autopilot! Raymarine said to send it back for repair, great. Up and down the mast twice, and rethreading the cable isn't what I had in mind for an eighteen month old instrument........

 

[davidwf]

I've had one for 3 years and am happy with it, had a ST60 with Vane on previous 2 boats and have to say that the rotarvector works fine compared to them. I don't sail to the instrument though I always use the tell tales on sails so perhaps I'm not asking too much from it.

Only real differences I've noticed is that it needs a higher wind speed than the vane to get a reasonably accuate reading. I also think its more succeptable to healing angle.

 

[double_ender]

I've had the older version st30 with the rotavecta for about 9 years, without any problem, except when it caught a load of seagull crap which took a while to free off.

I would go for the st40 again. I dont sail by the indicated value, I use the sails and the feel of the boat.

 

[DaveS]

I've been using a rotovecta for a year and it's been fine. It was a bit of a distressed purchase because my previous vane based system died. I can't say I've noticed any great difference in accuracy between the new unit and the the old (while it was working, I mean, before some smart@rse makes the obvious comment...)

 

[DaveS]

Ah...

I didn't expect that to happen. /forums/images/graemlins/blush.gif

I wonder if anyone will email? /forums/images/graemlins/smile.gif

 

[rogerhudson]

I would like to know how a rotavecta can tell angle anyway? what physics does it use?

 

[DaveS]

Another thread raised from the dead!

The rotovecta has three normal anemometer cups, but one of them has an additional "tab". The idea is that this cup is driven faster downwind and slower upwind than the other two, so the speed of the anemometer is not constant but incorporates a "wobble" component. The position of this wobble depends on apparent wind direction so it can be analysed to derive wind direction. It's a clever idea, and means that only two wires are required up the mast.

On a practical level, my Raymarine 40 wind gizmo worked fine for a couple of years, limped along (memory loss) for another 2 years then packed up completely. It is now replaced by another make.

 

[Boo2]

...The position of this wobble...

Compared with what ?

Boo2

 

[Neeves]

We have used the ST30 wind for 12 years. Its fine, you get what you pay for. If you want to rely on the electronics go for the better range, ST60. If you want an idea of wind speed, its fine. Does it matter if its out by 10%, you can feel what you need to know. Same goes for direction, tell tales are there - they are more accurate than anything else anyway.

If I had the money I'd buy ST60 if I had something else to buy, I'd go for the ST40 (again).

We have just replaced the display, 12 years life is not bad.

Jonathan

 

[DaveS]

Compared with what ?

Boo2

A fixed position.

For example, when motoring directly into the wind or at tide-free anchor the anemometer accelerates as the tab moves aft and decelerates as the tab moves forward so the rotational speed is at a minimum when the tab points forward. With wind from another direction this position of minimum speed changes to the direction of the new apparent wind.