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    Posted: 13 Sep 12 at 1:31pm
Like the idea about two boat tuning - increases the market too!

I definitelty agree about a more precise approach to boat tuning - how many times did 'marginal gains' get mentioned at the Olympics?
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 2:01pm
Originally posted by Peaky

Like the idea about two boat tuning - increases the market too!

I definitelty agree about a more precise approach to boat tuning - how many times did 'marginal gains' get mentioned at the Olympics?


About as often as race-tracks and the playing of jokers - but maybe they got it right on the marginal gains?
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Post Options Post Options   Quote Lukepiewalker Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 2:46pm

http://cosworth.com/products/marine/performance-sailing/pi-garda-data-logger/

How is that 'inclinometer' going to work in waves? Just out of interest, if you are talking 1/2 a degree of heel would you not get dizzy watching the output?

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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 3:13pm
I believe the basic Pi Garda is based around GPS, whereas this is built on an IMU (inertial measurement unit) with a Kalman filter to get accurate heading and attitude (heading being direction the bow is pointing, not moving - couple it with GPS to get leeway angle). The Pi is also v expensive, I believe.

The sampling rate and accuracy of the gyros and acclerometers is plenty good enough to cope with waves. Even in waves I think you would want to know how averagely flat you were and how much you pitched as you worked through the waves.


Edited by Peaky - 13 Sep 12 at 3:14pm
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Post Options Post Options   Quote Kev M Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 3:57pm
How would you go about zeroing the gyros to the boat so that you knew level was level?
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 4:44pm
Good question - accelerometers. An inertial measurement unit uses gyro's and accelerometers (and magnetometers in this case, for heading). The combination allows accurate attitude and heading to be measured, and is commonly used for inertial guidance and inertial navigation systems (aeroplanes, missiles, etc). With modern technology it is now possible to create accurate 'consumer' versions at reasonable prices.

They can also be used for speed and location, but suffer badly from drift, hence the need combine with GPS to 'refix' periodically (which gives much better results than GPS alone).
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Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 4:56pm
Originally posted by Kev M

How would you go about zeroing the gyros to the boat so that you knew level was level?

Good question, one I'm sure pond monkey is awaiting the answer to with baited breath, zeroing the gyros on his extreme coffin must be almost important as knowing how far up the gunwales fresh water is going to climb with his great bulk on board..If it's not level we all know what's going to happen.

It'll be just like overfilling a wineglass then being summoned to the other side of the room by a pretty girl only in reverse..
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 5:19pm


I might have misunderstood your question Kev. How do you know the device is mounted to a bit of boat parallel to the waterplane? I guess you have to measure or make an educated guess. A Laser foredeck looks pretty level to me.
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Post Options Post Options   Quote Kev M Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 6:56pm
Originally posted by Peaky



I might have misunderstood your question Kev. How do you know the device is mounted to a bit of boat parallel to the waterplane? I guess you have to measure or make an educated guess. A Laser foredeck looks pretty level to me.

That's the point I was trying to make.  With all this talk of getting the boat flatter by a degree or so, the difference between the zero position of the gyro held in a case and the waterline could easily be more than the in both fore/aft and port/stbd planes.

Added to that, a boat (in my limited experience) is never in one position, level or otherwise for more than few seconds as it's always moving around and you're always adjusting to compensate.  With that in mind the device would need some pretty fancy stuff going on to take the natural movement into account and come up with a mean position I'd have thought.
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 13 Sep 12 at 7:57pm
Some boats have a flat place, like Lasers, so that would be easy. For others you may to press a "set" button, either with the boat level on a trolley or in calm water.

In some ways it wouldn't matter as long as it was placed consistently.
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