GNAV - pros and cons?

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perhamh
Posts: 38
Joined: Thu Oct 02, 2014 11:41 am

GNAV - pros and cons?

Post by perhamh » Fri Nov 27, 2020 10:21 am

Heading says it all, really. I like the idea of a clear working area forward of the slide, where you want to be in very light weather, and of ending those embarrassing moments coming ashore when the main foil is lifted and the boom turns out to be on the wrong side of the kicker. Cons presumably include mild deformation of the flow across the main (though low down), and spar weight.

First, a technical question: must the GNAV be fixed on the mast, and tracked on the boom, or could it be the other way round?

Next, are lowers a must-have with a GNAV? What about if the gooseneck is as low as possible, either on the foot of a deck-stepped mast or even below it)? Obviously there's a trade-off between gooseneck height and the benefits I'm looking for. Or is a GNAV somehow compatible with a cranked boom? - seems unlikely.

Anyone out there with relevant experience, in ICs or otherwise?

Perham
GBR ???

chrishampe
Posts: 268
Joined: Sat Feb 02, 2008 12:24 pm
Location: Plymouth, Devon, UK

Re: GNAV - pros and cons?

Post by chrishampe » Fri Nov 27, 2020 6:49 pm

Never used one myself But here are my 2 cents:

Gnavs can be either fixed at the mast end or boom end, I would expect that lowers would be prefered to help control mast bend or you would need an extra thick wall section for the lower part of the mast.

I know Charlie Chandler didn't like the gnav on the Aus boat he had, so may be worth giving him a shout.
________________________
Chris Hampe
GBR 340 Monkey's Uncle

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