7 replies to this topic

[Vincent DePillis]

Remeber Dave Hollum's articles in Seahorse dismissing the value of a gybing board?


Interesting to see the following in Seahorse #386, at page 44:

“So a choice was made to opt for a single lifting board butone that “gybes” automatically upwind to a preset angle of attack – like agiant 505 dinghy! …. Using our previous 60 footer, Solune , We hadalready evaluated this foil solution against a conventional board plus trim tabat full scale; Shamlor’s gybing board arrangement comes out well ahead.”



This in context of an open 60 themed luxury yacht. It would be nice if Seahorse would press the author, Axel de Beaufort, for technical backup for this assertion.

[IC Nutter]

I haven't read the article but...

If the yacht is designed to sail normally at an angle of heel, then there could be some significant benefit to using a gybing board. Open 60 style hulls have very asymmetric waterlines when heeled, so the aim would be to align the foil with the heeled waterline axis. This is not the case with with a dinghy designed to be sailed with no heel, in which case the advantage of a gybing board is marginal at best.

[bruno]

Hollom had some interesting points, smart guy. Gybers have gone in and out of fashion 3 times, I think, in the past 40 years, I wonder if they are so clearly advantaged why they don't stick. My sense has been that in flat water they can make a difference but once in chop they don't work so well. Hollom has done some complex analysis, I'm just going off gut and empirical. It seemed like at the start in lighter conditions they could give you room to breathe, after that it didn't seem so dominant. I guess on a a wide heeled keelboat (as noted) might help (like angled daggers) but I don't think that I'd want one floppiing around for thousands of miles, lot of chafe.

[Amati]

I think once you get to a certain level of theoretical and practical knowledge in fluid dynamics, you only seem mad, much as poets, theoretical mathematicians, philosophers and composers, among others can seem quite mad.

It may be that jibing boards are chiefly a form (or means) of artistic expression.

[herr_zorzs]

I think once you get to a certain level of theoretical and practical knowledge in fluid dynamics, you only seem mad, much as poets, theoretical mathematicians, philosophers and composers, among others can seem quite mad.

It may be that jibing boards are chiefly a form (or means) of artistic expression.

haha, i love that!

[dogwatch]

Remeber Dave Hollum's articles in Seahorse dismissing the value of a gybing board?

I think you mean Hollom.

[Daniel Holman]

I think that this is true - most of the nominally brightest, most intelligent academically minded people are barely able to wash and clothe themselves, let alone communicate with "normal" human beings.
Whilst I am sure that a fluid dynamicist would be very good at designing a 2d foil section with 0.01% less profile drag than a vanilla NACA01234 or whatever, it is rare that one can look at the holistic picture of yacht design, or from the salt caked blistered viewpoint of the end user.

Gybing boards are good on paper, but involve compromises in most cases, and also rely heavily on the quality of their actual execution on a boat (not straightforward) and the correct use by the sailor. Do you think the average dinghy sailor is going to give a fuck or have a clue about whether his board is set to 3 or 5 degrees of gybe, or how that suits the leeway angle at the current combination of speed and righting moment? Course not. If he/she is any good they'll be fairly well absorbed by the niceties of sheet / tiller / weight and managing their tactics and strategy.

[Amati]

Dan, one way to make your point would be to have a tiller on a jibing cb or db, and have the crew conrol it with a hiking stick. New levels of control and teamwork!